Competitive strategies for water availability in two Mediterranean Quercus species - Nardini, A.; Gullo, M. A. Lo; Salleo, S. (Plant, Cell & Environment, 1999)
Competition for water availability was studied in a mixed natural stand of Quercus suber L. and Quercus cerris L. growing in Sicily by measuring diurnal changes of leaf conductance to water vapour (gL), water potential (ΨL) and relative water content (RWC) in April, July and October 1997 as well as the seasonal changes in root hydraulic conductance per unit leaf surface area (KRL). Quercus cerris behaved as a drought-tolerant species, with strong reductions of KRL, ΨL, and RWC in the summer. By contrast, Q. suber appeared to withstand summer drought by an avoidance strategy based on reducing gL, maintaining ΨL and RWC high and KRL at the same level as that measured in the spring. A ‘conductance ratio’ (CR) was calculated in terms of the ratio of gL to KRL. Seasonal changes of this ratio contrasted in the two species, thus suggesting that Q. suber and Q. cerris did not really compete for available water. In the summer, when Q. suber was extracting water from the soil to maintain high leaf hydration, Q. cerris had restricted water absorption, thus suffering drought but tolerating its effects. The possibility that cohabitation of drought-tolerant with drought-avoiding species can be generalized is also discussed.
Keywords: leaf conductance; leaf water status; Quercus cerris (Turkey Oak); Quercus suber (cork oak); root hydraulic conductance.

Competitive strategies for water availability in two Mediterranean Quercus species - Nardini, A; Gullo, M A Lo; Salleo, S (Plant, Cell & Environment, 1999)
Competition for water availability was studied in a mixed natural stand of Quercus suber L. and Quercus cerris L. growing in Sicily by measuring diurnal changes of leaf conductance to water vapour (gL), water potential (ΨL) and relative water content (RWC) in April, July and October 1997 as well as the seasonal changes in root hydraulic conductance per unit leaf surface area (KRL). Quercus cerris behaved as a drought-tolerant species, with strong reductions of KRL, ΨL, and RWC in the summer. By contrast, Q. suber appeared to withstand summer drought by an avoidance strategy based on reducing gL, maintaining ΨL and RWC high and KRL at the same level as that measured in the spring. A ‘conductance ratio’ (CR) was calculated in terms of the ratio of gL to KRL. Seasonal changes of this ratio contrasted in the two species, thus suggesting that Q. suber and Q. cerris did not really compete for available water. In the summer, when Q. suber was extracting water from the soil to maintain high leaf hydration, Q. cerris had restricted water absorption, thus suffering drought but tolerating its effects. The possibility that cohabitation of drought-tolerant with drought-avoiding species can be generalized is also discussed.
Keywords: leaf conductance; leaf water status; Quercus cerris (Turkey Oak); Quercus suber (cork oak); root hydraulic conductance.

Contribution to the extensification/intensification debate: new trends in the Portuguese montado - Pinto-Correia, T; Mascarenhas, J (Landscape and Urban Planning, 1999)
The montado is the agro-silvo pastoral system speci®c to the region of Alentejo, Southern Portugal, comprising an open formation of cork and holm oaks in varying densities, combined with a rotation of crops/fallow/pastures. Case studies in different areas of Alentejo, combining the land use and the farmers' decision making, have shown recent extensi®cation in different sub-types of montado. The agro-silvo pastoral system is in transition towards a silvo-pastoral or even purely forestry system. Cultivation is becoming less important in the system rotation, whereas livestock production is becoming more relevant and the ground cover is used only as pasture. The cork is still valuable and, in most cases, is the ®rst priority in the exploitation. New alternative uses are arising; they include hunting and rural tourism, both intended to support the preservation of the traditional landscapes. All these uses are supported directly or indirectly by the EU's CAP; for example, through agro-environmental measures. Although scrub patches are becoming larger, complete land abandonment is rare. These land use systems are based on a use that is even more extensive. Consequently the landscape is changing, but a new equilibrium, displaying new land cover mosaics, might be attained. Concomitantly, intensi®cation is occurring in certain areas. It causes degradation as a result of various management factors: (a) harvesting activity and deep ploughing in the areas where crops are cultivated, (b) too high stocking rates in relation to the carrying capacity of the system, impeding, for example, the natural regeneration of the tree cover; (c) introduction of heavy cattle breeds, which aggravates the problem of overstocking and results in direct damage to the soil structure and to the tree root system. The clearing of the shrub layer with heavy machinery affects the Quercus regeneration in both extensively and intensively managed patches, but no effective alternatives have yet been found. Today, the main landscape problem of the montado is not the abandonment of the system due to extensi®cation, but is rather: (1) whether the current extensi®cation is leading to a new equilibrium in an extensive silvo-pastoral or merely forestry system, and what type of landscape mosaic this change is creating; and (2) whether it is possible to avoid short-term intensi®cation and improve mechanisation to clear shrubs without degradation; (3) to what extent these changes depend on the CAP and how they will react to CAP changes in the future.
Keywords: extensification; intensification; land use; landscape; montado

Cork oak - Hypoxylon mediterraneum de Not.: pathogenicity tests - Santos, M N S (PHYSIOLOGY AND GENETICS OF TREE-PHYTOPHAGE INTERACTIONS - INTERNATIONAL SYMPOSIUM, 1999)
Hypoxylon mediterraneum (de Not.) Mill. is a fungus closely associated with cork oak trees in the last stage of decline. This fungus has frequently been considered a strong contributory factor to cork oak decline. Observations and experiments conducted under field conditions, raise doubts about the role of the fungus even in late stages of decline. To clarify this situation several attempts were made to assess fungus pathogenicity. The results obtained confirmed that the fungus develops on previously killed tissues, leading to the hypothesis that H. mediterraneum probably functions as a saprophyte.

Cuticular waxes of the holm (Quercus ilex l. subsp. ballota (desf.) samp.) and cork (Q. suber l.) oaks - Martins, C. M. C.; Mesquita, S. M. M.; Vaz, W. L. C. (Phytochemical Analysis, 1999)
The epicuticular leaf waxes of young leaves of the Holm oak (Quercus ilex L. ssp. ballota (Desf.) Samp.) and the cork oak (Q suber L.) were extracted in chloroform and separated into their constituent wax classes by preparative thin layer and high pressure liquid chromatography. The wax coverage was about 125 μg/cm2 in Q. suber and about 71 μg/cm2 in Q. ilex. The main classes encountered (by weight) were odd chain n-alkanes (9% in Q. ilex, and 4–27% in Q. suber) and even chain amphiphilic compounds. The major classes of amphiphilic compounds were n-alkan-1-ols (20–27% in Q. ilex, and 18–50% in Q. suber), n-alkanals (<3% in Q. ilex, and up to 25% in Q. suber), n-alkanoic acids (11–12% in Q. ilex, and <5% in Q. suber) and n-alkyl esters (50–56% in Q. ilex, and 25–45% in Q. suber). The major components of each class, identified by gas chromatography coupled to mass spectrometry were C29 for the n-alkanes (54–58% in Q. ilex, and 47–57% in Q. suber), C24 for the n-alkan-1-ols (78–87% in Q. ilex, and 77–93% in Q. suber), C30 for the n-alkanals (up to 57% in Q. ilex, and up to 77% in Q. suber), C22 and C24 for the n-alkanoic acids in Q. ilex (39–62%) and C30 in Q. suber (49%). The n-alkyl esters were composed mainly from C22 and C24n-alkanoic acids (∼38%) and n-alkan-1-ols (43–54%) in Q. ilex, whereas in Q. suber these esters were composed mainly from C22 and C24n-alkanoic acids (44–52%) and C20 and C22n-alkan-1-ols (32–66%). In addition to the above compounds, trace amounts (<5%) of C28 and C30n-alkenes and the triterpenone, friedelin, were encountered in Q. suber and both plant waxes contained small amounts of the triterpenols α- and β-amyrin (5–9% of the total alkanol content). The variability observed in the chemical composition of the leaf waxes were attributable to seasonal causes and/or leaf age. Copyright © 1999 John Wiley & Sons, Ltd.
The following values have no corresponding Zotero field: publisher: John Wiley & Sons, Ltd.
Keywords: chemical composition; cuticle; cuticular waxes; Quercus ilex; Quercus suber

Cuticular waxes of the holm (Quercus ilex l. subsp. ballota (desf.) samp.) and cork (Q. suber l.) oaks - Martins, C M C; Mesquita, S M M; Vaz, W L C (Phytochemical Analysis, 1999)
The epicuticular leaf waxes of young leaves of the Holm oak (Quercus ilex L. ssp. ballota (Desf.) Samp.) and the cork oak (Q suber L.) were extracted in chloroform and separated into their constituent wax classes by preparative thin layer and high pressure liquid chromatography. The wax coverage was about 125 μg/cm2 in Q. suber and about 71 μg/cm2 in Q. ilex. The main classes encountered (by weight) were odd chain n-alkanes (9% in Q. ilex, and 4–27% in Q. suber) and even chain amphiphilic compounds. The major classes of amphiphilic compounds were n-alkan-1-ols (20–27% in Q. ilex, and 18–50% in Q. suber), n-alkanals (<3% in Q. ilex, and up to 25% in Q. suber), n-alkanoic acids (11–12% in Q. ilex, and <5% in Q. suber) and n-alkyl esters (50–56% in Q. ilex, and 25–45% in Q. suber). The major components of each class, identified by gas chromatography coupled to mass spectrometry were C29 for the n-alkanes (54–58% in Q. ilex, and 47–57% in Q. suber), C24 for the n-alkan-1-ols (78–87% in Q. ilex, and 77–93% in Q. suber), C30 for the n-alkanals (up to 57% in Q. ilex, and up to 77% in Q. suber), C22 and C24 for the n-alkanoic acids in Q. ilex (39–62%) and C30 in Q. suber (49%). The n-alkyl esters were composed mainly from C22 and C24n-alkanoic acids (∼38%) and n-alkan-1-ols (43–54%) in Q. ilex, whereas in Q. suber these esters were composed mainly from C22 and C24n-alkanoic acids (44–52%) and C20 and C22n-alkan-1-ols (32–66%). In addition to the above compounds, trace amounts (<5%) of C28 and C30n-alkenes and the triterpenone, friedelin, were encountered in Q. suber and both plant waxes contained small amounts of the triterpenols α- and β-amyrin (5–9% of the total alkanol content). The variability observed in the chemical composition of the leaf waxes were attributable to seasonal causes and/or leaf age. Copyright © 1999 John Wiley & Sons, Ltd.
Keywords: chemical composition; cuticle; cuticular waxes; Quercus ilex; Quercus suber

Datos sobre la flora y vegetación del Parque Natural de los Alcornocales (Cádiz-Málaga, España) - Pérez Latorre, A. V. (Acta botánica malacitana, 1999)
We have carried out a study about the flora, vegetation and landscape inthe Natural Park Los Alcornocales, located in the provinces of Cádiz and Málaga (SW of the Iberian Peninsula, Andalusia). The maximum altitude in the Park is 1091 m.; the dominant litology is characterised by sandstones and clays, in the NW prevail the limestones. The annual rainfalls are very abundant (between 800 and 1400 mm.) as well as the fogs regime, caused by the nearness to the Strait of Gibraltar; we have recognized two bioclimactic belts, thermo (annual mean temperature 17-18°C) and mesomediterranean (14-16°C) with accused oceanity. As a result, more than 1300 taxa of vascular plants have been catalogued, emphasizing in this work 77, because they are protected species, endemics or first records for western Andalusia; among them, 9 species are relictic ferns and have a great phytogeographic value. A total of 89 associations and communities have been inventoried. We have accomplished commentaries on sintaxa with a range superior to association. We lectotypified a subassociation and one association is neotypified. We describe as new sintaxa one order (Rhododendro pontici-Prunetalia lusitanicae), two alliances ldodendro ponticiPrunion lusitanicae and Salicion pedicellatae), 6 associations, 8 subassociations ad 1 combination. We have recognized 6 climactic series, among them one is new and characterised by forests of Quercus:broteroi on calcareous soils (Oleo sylvestris-Querceto broteroi S), other two are forests of Quercus suber on sandstones, another one is characterised by Quercus canariensis in wet slopes, one of Quercus pyrenaica in the summits and one of Quercus rotundifolia on lowland calcareous soils. As a mixed serie bound to the conditions of the vertisols occurs forests ofOlea sylvestris. As permanent vegetation on calcareous solis appears Ceratonia siliqua; on sandstones appears Junipertts oxycedrus; in summits flogged by strong winds we recognize a community with Quercus lusitanica and on rocky sandstones a relictual variant with Pinus pinaster. A mixed serie bound to the environmental humidity conditions as well as to wet soils is characterized by Rhododendron ponticum, similar to the macaronesian laurisilva. The series linked to rivers in the Park are characterised by: Alnus glutinosa (permanent stream rivers on sandstones), Salix pedicellata (partially droughted rivers), Populus alba (fluvisols), Fraxinus angustifolia (riverine sandyargilic soils), Nerium oleander (totally droughted rivers), Tarnarix africana (erratic or halophyll streams) and wet heaths with Erica ciliaris. Also exist communities mosaics bound to ecological corridors, human environments, rocks and cliffs, epiphytes, acrohalophylls and those tipycal of saline and aquatic environments. Finally, a commented syntaxonomic scheme, some inventories tables corresponding to the new or commented syntaxa and a map of the vegetation series of the Park are presented
Keywords: Andalucía; España; Flora; Los Alcornocales; Natural Park; sintaxonomy; Vegetation

Datos sobre la flora y vegetación del Parque Natural de los Alcornocales (Cádiz-Málaga, España) - Pérez Latorre, A V (Acta botánica malacitana, 1999)
We have carried out a study about the flora, vegetation and landscape inthe Natural Park Los Alcornocales, located in the provinces of Cádiz and Málaga (SW of the Iberian Peninsula, Andalusia). The maximum altitude in the Park is 1091 m.; the dominant litology is characterised by sandstones and clays, in the NW prevail the limestones. The annual rainfalls are very abundant (between 800 and 1400 mm.) as well as the fogs regime, caused by the nearness to the Strait of Gibraltar; we have recognized two bioclimactic belts, thermo (annual mean temperature 17-18°C) and mesomediterranean (14-16°C) with accused oceanity. As a result, more than 1300 taxa of vascular plants have been catalogued, emphasizing in this work 77, because they are protected species, endemics or first records for western Andalusia; among them, 9 species are relictic ferns and have a great phytogeographic value. A total of 89 associations and communities have been inventoried. We have accomplished commentaries on sintaxa with a range superior to association. We lectotypified a subassociation and one association is neotypified. We describe as new sintaxa one order (Rhododendro pontici-Prunetalia lusitanicae), two alliances ldodendro ponticiPrunion lusitanicae and Salicion pedicellatae), 6 associations, 8 subassociations ad 1 combination. We have recognized 6 climactic series, among them one is new and characterised by forests of Quercus:broteroi on calcareous soils (Oleo sylvestris-Querceto broteroi S), other two are forests of Quercus suber on sandstones, another one is characterised by Quercus canariensis in wet slopes, one of Quercus pyrenaica in the summits and one of Quercus rotundifolia on lowland calcareous soils. As a mixed serie bound to the conditions of the vertisols occurs forests ofOlea sylvestris. As permanent vegetation on calcareous solis appears Ceratonia siliqua; on sandstones appears Junipertts oxycedrus; in summits flogged by strong winds we recognize a community with Quercus lusitanica and on rocky sandstones a relictual variant with Pinus pinaster. A mixed serie bound to the environmental humidity conditions as well as to wet soils is characterized by Rhododendron ponticum, similar to the macaronesian laurisilva. The series linked to rivers in the Park are characterised by: Alnus glutinosa (permanent stream rivers on sandstones), Salix pedicellata (partially droughted rivers), Populus alba (fluvisols), Fraxinus angustifolia (riverine sandyargilic soils), Nerium oleander (totally droughted rivers), Tarnarix africana (erratic or halophyll streams) and wet heaths with Erica ciliaris. Also exist communities mosaics bound to ecological corridors, human environments, rocks and cliffs, epiphytes, acrohalophylls and those tipycal of saline and aquatic environments. Finally, a commented syntaxonomic scheme, some inventories tables corresponding to the new or commented syntaxa and a map of the vegetation series of the Park are presented
Keywords: Andalucía; España; Flora; Los Alcornocales; Natural Park; sintaxonomy; Vegetation

Dehesa ecosystem: Production and preservation - Olea, L; Figuera, F (Options Méditerranéennes, 1999)
The Dehesa is an ecosystem in which species of herbs, bushes and trees coexist in a semi-desert regime, contributingto the feeding of domestic and wild animals. The improvement and exploitation of these agrosylvopastoral systems must be founded on the principles of preseofr vthaetio ne nvironment and the idea of creating systems that can be maintained with a correct usage of natural resources. Fertilization of the natural pastures, the introduction of new pasture species and varieties, the favouring of the species of bush that have a forage value and the preservationo f the arboreous stratum are methods which will alluosw t o preserve this ecosystem
Keywords: Dehesa; forages; iberian peninsula; pastures

The dehesa system of southern Spain and Portugal as a natural ecosystem mimic - Joffre, R; Rambal, S; Ratte, J P (Agroforestry Systems, 1999)
The dehesas of the southwestern Iberian Peninsula are ‘man-made’ ecosystems characterised by a savannah-like physiognomy. The trees are viewed as an integrated part of the system, and as a result are planted, managed, and regularly pruned. Palynological and historical evidence of the manipulation of initial ecosystems by man to obtain a savannah-like ecosystem is presented. The ecological functions of the tree are detailed using results obtained at two complementary scales. At the local scale, strong soil structural differences and functional differences in water budget and patterns of water use are observed under and outside the tree canopy. Using the concept of ecosystem mimicry, the two coexistent components of dehesas can be compared to two distant stages of a secondary succession characterised by very different behaviours. At the regional scale, evidence of relationships between tree density and mean annual precipitation over more than 5000 km2 suggests that the structure of these man-made agroecosystems have adjusted over the long-term and correspond to an optimal functional equilibrium based on the hydrological equilibrium hypothesis. Finally, the future of dehesas in the face of contemporary exogenous threats of economic and global environmental origin is discussed. 1. Introduction
Keywords: hydrological equilibrium; Mediterranean climate; optimality; Quercus ilex; Quercus suber; water balance

Dendroanalysis: a tool for biomonitoring environmental pollution? - Nabais, C; Freitas, H; Hagemeyer, J (The Science of the total environment, 1999)
Trees of temperate regions usually form visible annual growth rings, which can be dated accurately. It is therefore possible to collect wood samples of different age and analyse their heavy metals content in order to get a chronological record of trace elements pollution in the tree's environment. This method of retrospective biomonitoring was called dendroanalysis. A basic assumption of dendroanalysis is the stability of the mineral distribution patterns, i.e. once the elements are stored, no significant mobility should occur. Additionally, neighbouring trees growing in the same environment should show similar radial element patterns. While some studies presented good correlations between radial distributions of heavy metals in tree rings and temporal records of pollution from industry or traffic, others failed in using dendroanalysis as a chronological record of pollution. Probably some elements can move at a certain rate in radial direction through the ray parenchyma cells. In this way the radial element distributions are subsequently changed. Growth rates of tree rings can also influence the concentrations of elements in wood. During periods of slow growth higher concentrations of elements can be found in the wood. Therefore, radial distribution patterns of heavy metals in tree rings should be used with caution as a tool for retrospective biomonitoring of environmental pollution.
Keywords: biomonitoring; Dendroanalysis; Heavy metals

Detection of vegetation stress and nutrient deficiencies by leaf laser-induced fluorescence imaging - Heisel, F; Sowinska, M; Eckert, C; Miehe, J A (INTERNATIONAL SYMPOSIUM ON URBAN TREE HEALTH, 1999)
A high spatial resolution fluorescence imaging set-up developed in our laboratory has been used to study the effects of several stress factors on the fluorescence characteristics of various plants. Measurement campaigns, of agricultural interest, have made obvious for example: a strong and specific heterogeneity of the chlorophyll emission distribution at the surface of vine leaves (Vitis Vinefera `Riesling') suffering from different mineral stress for increasing nitrogen fertilisation of wheat (Triticum aestivum L., `Soissons'), a readily decrease of the blue/red and blue/far-red emissions ratios, which were found the most sensitive indicators of a nitrogen deficiency in the case of apple-trees (Malus x domestica Borkh.cv.'Jonagold 2361') an effect of nitrogen supply on the chlorophyll emission intensities, in an opposite way for 355 nm excitation for the rosette leaves than for the leaves from the youngest branches for oak (Quercus ilex) and beech (Fagus sylvatica), an important enhancement of the chlorophyll emission when the solar irradiance during growth is strongly reduced.
Keywords: irradiance; mineral or nitrogen deficiency; vine

The development of a protocol for the encapsulation-desiccation and in vitro culture of embryonic axes of Quercus suber L-and Q-ilex L. - Gonzalez-Benito, M E; Herradon, E; Martin, C (SILVAE GENETICA, 1999)
Quercus species have seeds recalcitrant against long-term storage. Cryopreservation of embryonic axes could be a feasible way of preserving their genetic diversity. Several cryopreserva- tion protocols are based on desiccation, among them the so- called encapsulation-dehydration. However, it is previously necessary to establish an adequate in vitro culture develop- ment of desiccated axes. Embryonic axes of Q. suber and Q. ilex were aseptically excised, encapsulated in alginate beads, cultur- ed in a sucrose-rich liquid medium, desiccated for different periods in a flow bench and cultured on basal WPM medium. Moisture content of encapsulated axes dropped from 74% to 71% (fresh weigh basis) to 24.5% to 21% after 6 h desiccation, respectively for the two species. Germination decreased to 20% in both species. Germination and shoot elongation of encapsu- lated embryos (non-desiccated or desiccated for 4 h) was stud- ied for both species after culture on WPM medium supplemented with different concentrations of BAP and IBA. Medium with 0.1 mgl-1 BAP resulted in a high percentage of germina- tion and development of shoots in both species
Keywords: aliginate bead; Dehydration; in vitro culture; oak; Quercus; recalcitrant seed

Development of cork–gypsum composites for building applications - Hernández-Olivares, F; Bollati, M R (Construction and Building Materials, 1999)
This paper presents an experimental analysis on a new composite material, cork]gypsum composite. It is shown that cork and plaster are mutually compatible and that a lot of new building materials can be made by mixing those materials in different volume fractions. Mechanical properties of the cork]gypsum composite have been measured. The acoustic absorption coefﬁcient and thermal conductivity of this new composite have also been experimentally obtained and those values are reported for design purposes. Concerning the acoustical insulation characteristics, this composite is not a sound-absorbing material but a reﬂecting one, and it needs some kind of perforations to behave as an absorbing construction material for sound and noise. The thermal insulation properties are quite good as a result of the thermal conductivity tests. This new composite material is suggested for use in building applications as partitions.
Keywords: acoustics; Building materials; cork-gypsum; partitions; walls

Developmental anatomy and apical organization of the primary root of cork oak (Quercus auber L. - Verdaguer, Dolors; Molinas, Marisa (International Journal of Plant Sciences, 1999)
Using histological techniques, we investigated the development and organization of the primary root and the root apex of Quercus suber L. (cork oak), a Mediterranean woody species growing in semiarid conditions. The presence of a quiescent center was also investigated. The histogenesis of the vascular system begins with the maturation of the protophloem elements. Primary phloem and xylem strands form alternately, and maturation proceeds centripetally, although xylem differentiation does not reach the center of the root, which is occupied by a pith. Most protoxylem elements were fully mature well before the endodermis entered State I with the formation of the Casparian strip. A continuous vascular cambium forms before the initiation of the phellogen in the outermost pericyclic layer. In the primary root the apex has an open organization with four groups of initials: vascular cylinder initials, cortical initials, lateral root-cap initials, and columella initials. The quiescent center includes the vascular initials and some derivatives. These features contrast with the radicle in mature and germinating embryos that have a closed organization with three groups of initials and a wider quiescent center.
Keywords: development; meristem; primary root; Quercus suber; quiescent center; vascular development

Diurnal changes in antioxidant and carotenoid composition in the Mediterranean schlerophyll tree Quercus ilex(L) during winter - García-Plazaola, J. I.; Artetxe, Unai; BECERRIL, J. M.; Garcı, Ignacio (Plant Science, 1999)
Seasonal changes of pigment composition and antioxidant content were characterized in the Mediterranean evergreen holm oak (Quercus ilex L.). Higher contents of antioxidants and carotenoids, with a photoprotective role during winter, indicated that this period was highly stressful, so a study of diurnal changes in photosynthesis, pigments and carotenoids was conducted during January in sun and shade leaves. Sun and shade leaves were used to compare the effects due only to low temperature separate from those resulting from the interaction of light. During winter, a relatively high rate of CO2 ﬁxation on sun leaves represented an important sink for photosynthetic electrons contributing to the annual carbon balance of the plant. This high rate contrasted with a reduced Fv :Fm, even at predawn. This reduction was correlated with the accumulation of zeaxanthin at the expense of violaxanthin by de-epoxidation. Sun leaves were also protected by a higher concentration of antioxidants (ascorbate, glutathione and tocopherol) and carotenoids (except lutein epoxide). Ascorbate was 10–50-fold greater than the other antioxidants, indicating a central role in protection against photooxidative stress. Nevertheless those mechanisms were unable to avoid a loss of hydrophilic antioxidants (glutathione and ascorbate) and xanthophylls during the initial morning hours after dawn, indicating that the ﬁrst target of photooxidative damage was these molecules
Keywords: Holm oak; low-temperature stress; Mediterranean evergreens; photoinhibition; photoprotection; xanthophyll cycle

Diurnal changes in antioxidant and carotenoid composition in the Mediterranean schlerophyll tree Quercus ilex(L) during winter - Garcia-Plazaola, J I; Artetxe, Unai; BECERRIL, J M; Garcı, Ignacio (Plant Science, 1999)
Seasonal changes of pigment composition and antioxidant content were characterized in the Mediterranean evergreen holm oak (Quercus ilex L.). Higher contents of antioxidants and carotenoids, with a photoprotective role during winter, indicated that this period was highly stressful, so a study of diurnal changes in photosynthesis, pigments and carotenoids was conducted during January in sun and shade leaves. Sun and shade leaves were used to compare the effects due only to low temperature separate from those resulting from the interaction of light. During winter, a relatively high rate of CO2 ﬁxation on sun leaves represented an important sink for photosynthetic electrons contributing to the annual carbon balance of the plant. This high rate contrasted with a reduced Fv :Fm, even at predawn. This reduction was correlated with the accumulation of zeaxanthin at the expense of violaxanthin by de-epoxidation. Sun leaves were also protected by a higher concentration of antioxidants (ascorbate, glutathione and tocopherol) and carotenoids (except lutein epoxide). Ascorbate was 10–50-fold greater than the other antioxidants, indicating a central role in protection against photooxidative stress. Nevertheless those mechanisms were unable to avoid a loss of hydrophilic antioxidants (glutathione and ascorbate) and xanthophylls during the initial morning hours after dawn, indicating that the ﬁrst target of photooxidative damage was these molecules
Keywords: Holm oak; low-temperature stress; Mediterranean evergreens; photoinhibition; photoprotection; xanthophyll cycle

Efecto de los tratamientos silvopastorales en el crecimiento del alcornoque - Caritat, A.; Molinas, M.; Vilar, L.; Masson, Ph (Scientia gerundensis, 1999)
Comparative effects of shrub clearing and grazing on the apical and radial growth of the cork oak have been studied in four cork oak wood stations. Shoot growth segments and annual wood rings were measured in 10 selected trees in every plot. Average shoot elongation's oscillate between 2.5 to 4.8 cm; annual wood rings from 0.95 to 2.05 mm and annual radial growth of wood plus cork from 2.3 to 5.7 mm. Significative differences were found between silvo-pastoral treatments in relation to apical elongation. In treated plots, the apical growth of segments that reach the maximum elongation can be a 75% higher than in control plots. This increment on shoot growth can be explained by the decrease in plant competition and by the nutrient contribution of grazing. No significative effects of treatments on radial growth have been found.
Keywords: Alcornoque; crecimiento apical; Crecimiento radial; desbroce; pastoreo (voyant)

Efecto de los tratamientos silvopastorales en el crecimiento del alcornoque - Caritat, A; Molinas, M; Vilar, L; Masson, Ph. (Scientia gerundensis, 1999)
Comparative effects of shrub clearing and grazing on the apical and radial growth of the cork oak have been studied in four cork oak wood stations. Shoot growth segments and annual wood rings were measured in 10 selected trees in every plot. Average shoot elongation's oscillate between 2.5 to 4.8 cm; annual wood rings from 0.95 to 2.05 mm and annual radial growth of wood plus cork from 2.3 to 5.7 mm. Significative differences were found between silvo-pastoral treatments in relation to apical elongation. In treated plots, the apical growth of segments that reach the maximum elongation can be a 75% higher than in control plots. This increment on shoot growth can be explained by the decrease in plant competition and by the nutrient contribution of grazing. No significative effects of treatments on radial growth have been found.
Keywords: Alcornoque; crecimiento apical; Crecimiento radial; desbroce; pastoreo (voyant)

Effect of pre-lambing supplementation on milk production of Merino ewes at grazing - Gallego, F. L.; Parra, M. L.; Sanchez, F. P. (MILKING AND MILK PRODUCTION OF DAIRY SHEEP AND GOATS, 1999)
Milk production of Merino ewes has been studied under the effects of two different prelambing supplementations (4 and 7 weeks, L1 and L2, respectively). Throughout the trial, the ewes remained under extensive grazing in a ``dehesa{''} from Extremadura. Lambing took place in September and lactation continued until the 6(th) week. After weaning, the ewes were subjected to machine milking until drying in the 19(th) week. During milking, the ration for both lots was the same. Similar daily values of production potential were noted, being greater in L2, 12% during lactation (1120ml) and 14% in milking (375ml). The milk obtained by the lamb at 42 days of lactation (40 l) was 11% superior in lot 2. The difference in body condition is balanced out during the 90 days of milking during which the milk production obtained in L2 (27 l) represents a 16% improvement in production.
The following values have no corresponding Zotero field: periodical: MILKING AND MILK PRODUCTION OF DAIRY SHEEP AND GOATS issue: 95 pub-location: POSTBUS 220, 6700 AE WAGENINGEN, NETHERLANDS
Keywords: grazing and supplementation; Merino; milk production

Effect of pre-lambing supplementation on milk production of Merino ewes at grazing - Gallego, F L; Parra, M L; Sanchez, F P (MILKING AND MILK PRODUCTION OF DAIRY SHEEP AND GOATS, 1999)
Milk production of Merino ewes has been studied under the effects of two different prelambing supplementations (4 and 7 weeks, L1 and L2, respectively). Throughout the trial, the ewes remained under extensive grazing in a ``dehesa{''} from Extremadura. Lambing took place in September and lactation continued until the 6(th) week. After weaning, the ewes were subjected to machine milking until drying in the 19(th) week. During milking, the ration for both lots was the same. Similar daily values of production potential were noted, being greater in L2, 12% during lactation (1120ml) and 14% in milking (375ml). The milk obtained by the lamb at 42 days of lactation (40 l) was 11% superior in lot 2. The difference in body condition is balanced out during the 90 days of milking during which the milk production obtained in L2 (27 l) represents a 16% improvement in production.
Keywords: grazing and supplementation; Merino; milk production

Effects of aqueous extracts from Quercus ilex l. root bark, Punica granatum l. fruit peel and Artemisia herba-alba Asso leaves on ethanol-induced gastric damage in rats - Gharzouli, Kamel; Khennouf, Seddik; Amira, Smain; Gharzouli, Akila (Phytotherapy Research, 1999)
The gastroprotective effect of tannic acid and the aqueous extract of Quercus ilex L. root bark, Punica granatum L. fruit peel and Artemisia herba-alba Asso leaves was investigated in the rat against ethanol-induced damage. Tannic acid, Q. ilex and P. granatum extracts gave 100% precipitation of ovine haemoglobin in vitro, whereas A. herba-alba extract was devoid of any protein-binding property. Oral administration of these plant extracts or tannic acid induced a significant decrease in gastric lesions (47.7%–76%). The observed protection was more pronounced when the test solution was given at the same time with ethanol, except for Q. ilex extract. The acid content of the stomach was significantly increased by P. granatum (368%) and A. herba-alba (251%) extracts prepared in ethanol. It is suggested that monomeric and polymeric polyphenols can strengthen the gastric mucosal barrier. Copyright © 1999 John Wiley & Sons, Ltd.
Keywords: Artemisia herba-alba; Experimental gastric ulcer; gastric secretion; polyphenols; Punica granatum; Quercus ilex

Effects of disturbance caused by traditional Spanish rural land use on the regeneration of Cytisus multiflorus - Fernández-Santos, B; Gómez-Gutiérrez, J M; Moreno-Marcos, G (Applied Vegetation …, 1999)
. Cytisus multiflorus is a leguminous matorral shrub native to the NW Iberian Peninsula, where it is one of the most important species in the extension of matorral at the expense of set-aside agricultural land. Dehesas have traditionally been used for extensive livestock raising and matorral was periodically burnt, cut or pulled out. The two latter practices are now out of use. However, burning is more frequent than in the past. The effects of fire, cutting, and pulling out of C. multiflorus on its regeneration was studied in order to ascertain whether the presently increasing distribution of the species relates to firestimulated regeneration or to the reduction of other traditional practices. Three years after treatment two sets of parameters were determined: 1. Plant origin: seedlings and different ramet types ( ramets = resprout clumps), density, weight, and biomass as well as the percentage of resprouting. 2. Seed persistence at various soil depths. The possible mechanisms of breaking dormancy and plant emergence in different years after fire were studied in other experiments. The results suggest that the regeneration mechanism in C. multiflorus is stimulated by fire, but it is not an exclusive relationship. Stimulation occurs also after other disturbances leading to the total elimination of aerial biomass. The present expansion of the species does not appear to result from the abandonment of some traditional practices, such as cutting or pulling out, but from frequent fires (resulting in aerial-biomass elimination).
Keywords: Cutting; fire; Mediterranean shrubland; Pull-out; Ramet; seed bank; Seedling

Effects of disturbance caused by traditional Spanish rural land use on the regeneration of Cytisus multiflorus - Fernández-Santos, B.; Gómez-Gutiérrez, J. M.; Moreno-Marcos, G. (Applied Vegetation …, 1999)
. Cytisus multiflorus is a leguminous matorral shrub native to the NW Iberian Peninsula, where it is one of the most important species in the extension of matorral at the expense of set-aside agricultural land. Dehesas have traditionally been used for extensive livestock raising and matorral was periodically burnt, cut or pulled out. The two latter practices are now out of use. However, burning is more frequent than in the past. The effects of fire, cutting, and pulling out of C. multiflorus on its regeneration was studied in order to ascertain whether the presently increasing distribution of the species relates to firestimulated regeneration or to the reduction of other traditional practices. Three years after treatment two sets of parameters were determined: 1. Plant origin: seedlings and different ramet types ( ramets = resprout clumps), density, weight, and biomass as well as the percentage of resprouting. 2. Seed persistence at various soil depths. The possible mechanisms of breaking dormancy and plant emergence in different years after fire were studied in other experiments. The results suggest that the regeneration mechanism in C. multiflorus is stimulated by fire, but it is not an exclusive relationship. Stimulation occurs also after other disturbances leading to the total elimination of aerial biomass. The present expansion of the species does not appear to result from the abandonment of some traditional practices, such as cutting or pulling out, but from frequent fires (resulting in aerial-biomass elimination).
Keywords: Cutting; fire; Mediterranean shrubland; Pull-out; Ramet; seed bank; Seedling

Effects of electron beam irradiation on cork volatile compounds by gas chromatography mass spectrometry - Careri, M; Mazzoleni, V; Musci, M; Molteni, R (CHROMATOGRAPHIA, 1999)
The effects of electron beam irradiation on cork volatile compounds was studied at different doses (25, 100, 1000 kGy), Volatiles we:re isolated from cork using the dynamic headspace-sampling technique, then identified by gas chromatography-mass spectrometry (GC-MS). Similar gas chromatographic profiles were obtained for non-irradiated and irradiated corks. Quantitative differences induced by the three doses were evaluated by calculating peak areas for each compound identified. The quantitative differences between non-irradiated corks and those irradiated at 25 kGy were significant for only a few substances, when:as significant quantitative differences were found in samples irradiated at 100 and 1000 kGy. For these doses, the content of volatile compounds generally increased, especially that of aliphatic hydrocarbons and carbonyl compounds. The behaviour of radiolytic hydrocarbons indicates that the mechanisms proposed for their formation in irradiated foods could take place even in cork.
Keywords: cork volatiles; dynamic headspace sampling; electron beam irradiation; gas chromatography mass spectrometry; radiolysis-induced compounds

Effects of electron beam irradiation on cork volatile compounds by gas chromatography mass spectrometry - Careri, M.; Mazzoleni, V.; Musci, M.; Molteni, R. (CHROMATOGRAPHIA, 1999)
The effects of electron beam irradiation on cork volatile compounds was studied at different doses (25, 100, 1000 kGy), Volatiles we:re isolated from cork using the dynamic headspace-sampling technique, then identified by gas chromatography-mass spectrometry (GC-MS). Similar gas chromatographic profiles were obtained for non-irradiated and irradiated corks. Quantitative differences induced by the three doses were evaluated by calculating peak areas for each compound identified. The quantitative differences between non-irradiated corks and those irradiated at 25 kGy were significant for only a few substances, when:as significant quantitative differences were found in samples irradiated at 100 and 1000 kGy. For these doses, the content of volatile compounds generally increased, especially that of aliphatic hydrocarbons and carbonyl compounds. The behaviour of radiolytic hydrocarbons indicates that the mechanisms proposed for their formation in irradiated foods could take place even in cork.
The following values have no corresponding Zotero field: pub-location: ABRAHAM-LINCOLN-STRABE 46, POSTFACH 15 47, D-65005 WIESBADEN, GERMANY publisher: VIEWEG
Keywords: cork volatiles; dynamic headspace sampling; electron beam irradiation; gas chromatography mass spectrometry; radiolysis-induced compounds

Effects of forest fragmentation on the winter body condition and population parameters of an habitat generalist, the wood mouse Apodemus sylvaticus: a test of - Díaz, M.; Santos, T.; Tellería, J. L. (Acta Oecologica, 1999)
Three main causal hypotheses have been proposed to explain the inverse relationships between habitat patch size and density of gen- eralist mouse species in fragmented habitats: 1) enhanced habitat conditions as habitat patch size decreases; 2) inhibited emigration of excess indi- viduals in small and isolated habitat patches; and 3). reduced territoriality in small patches because they are occupied temporarily by non- reproductive individuals. From the mechanism underlying each hypothesis, we derived predictions on the effects of fragment size on the body condition of individuals (measured both as absolute body size and as body mass relative to body size) and some demographic parameters of mouse populations redated to reproductive output (sex-ratio and proportions of sexually active and recently-born individuals), and we tested such predic- tions with data from wood mice Apodemus sylvaticus wintering in three Spanish forest archipelagos in which the inverse relationship between for- est patch size and mouse abundance had been previously proven. No differences in average body size or in average body mass relative to body size were detected among fragments. Mouse populations wintering in small fragments showed more male-biased sex-ratios, a larger proportion of sex- ually active adults and fewer juveniles as compared to mouse populations wintering in large fragments nearby. Results clearly rejected the third hypothesis and did not support the second one. It thus seemed that habitat conditions for mice improved as forest fragment size decreased, although the expected positive effects on individuals could have been prevented by relaxed territoriality and increased food resource depletion by denser mouse populations. Bearing in mind the negative effects of dense wood mice populations on the distribution, abundance and population dynamics of forest species, this apparent enhancement of habitat conditions for mice in small forest fragments could have far-reaching conse- quences for the long-term persistence of such fragments.
Keywords: Body condition; Body size; demography; Forest fragmentation; population density; winter; wood mouse

Effects of forest fragmentation on the winter body condition and population parameters of an habitat generalist, the wood mouse Apodemus sylvaticus: a test of - Diaz, M; Santos, T; Tellería, J L (Acta Oecologica, 1999)
Three main causal hypotheses have been proposed to explain the inverse relationships between habitat patch size and density of gen- eralist mouse species in fragmented habitats: 1) enhanced habitat conditions as habitat patch size decreases; 2) inhibited emigration of excess indi- viduals in small and isolated habitat patches; and 3). reduced territoriality in small patches because they are occupied temporarily by non- reproductive individuals. From the mechanism underlying each hypothesis, we derived predictions on the effects of fragment size on the body condition of individuals (measured both as absolute body size and as body mass relative to body size) and some demographic parameters of mouse populations redated to reproductive output (sex-ratio and proportions of sexually active and recently-born individuals), and we tested such predic- tions with data from wood mice Apodemus sylvaticus wintering in three Spanish forest archipelagos in which the inverse relationship between for- est patch size and mouse abundance had been previously proven. No differences in average body size or in average body mass relative to body size were detected among fragments. Mouse populations wintering in small fragments showed more male-biased sex-ratios, a larger proportion of sex- ually active adults and fewer juveniles as compared to mouse populations wintering in large fragments nearby. Results clearly rejected the third hypothesis and did not support the second one. It thus seemed that habitat conditions for mice improved as forest fragment size decreased, although the expected positive effects on individuals could have been prevented by relaxed territoriality and increased food resource depletion by denser mouse populations. Bearing in mind the negative effects of dense wood mice populations on the distribution, abundance and population dynamics of forest species, this apparent enhancement of habitat conditions for mice in small forest fragments could have far-reaching conse- quences for the long-term persistence of such fragments.
Keywords: Body condition; Body size; demography; Forest fragmentation; population density; winter; wood mouse

Effects of grazing and topography on long-term vegetation changes in a Mediterranean ecosystem in Israel - Carmel, Yohay; Kadmon, Ronen (Plant Ecology, 1999)
The dynamics of Mediterranean vegetation over 28 years was studied in the Northern Galilee Mountains, Israel, in order to identify and quantify the major factors affecting it at the landscape scale. Image analysis of historical and current aerial photographs was used to produce high resolution digital vegetation maps (pixel size = 30 cm) for an area of 4 km2 in the Galilee Mountains, northern Israel. GIS tools were used to produce corresponding maps of grazing regime, topographic indices and other relevant environmental factors. The effects of those factors were quantiﬁed using a multiple regression analyses. Major changes in the vegetation occurred during the period studied (1964–1992); tree cover increased from 2% in 1964 to 41% in 1992, while herbaceous vegetation cover decreased from 56% in 1964 to 24% in 1992. Grazing, topography and initial vegetation cover were found to signiﬁcantly affect present vegetation patterns. Both cattle grazing and goat grazing reduced the rate of increase in tree cover, yet even intensive grazing did not halt the process. Grazing affected also the woody-herbaceous vegetation dynamics, reducing the expansion of woody vegetation. Slope, aspect, and the interaction term between these two factors, signiﬁcantly affected vegetation pattern. Altogether, 56% and 72% of the variability in herbaceous and tree cover, respectively, was explained by the regression models. This study indicates that spatially explicit Mediterranean vegetation dynamics can be predicted with fair accuracy using few biologically important environmental variables.
Keywords: aerial photographs; GIS; landscape ecology; regression model; spatial structure; Vegetation dynamics

Effects of grazing and topography on long-term vegetation changes in a Mediterranean ecosystem in Israel - Carmel, Yohay; Kadmon, Ronen (Plant Ecology, 1999)
The dynamics of Mediterranean vegetation over 28 years was studied in the Northern Galilee Mountains, Israel, in order to identify and quantify the major factors affecting it at the landscape scale. Image analysis of historical and current aerial photographs was used to produce high resolution digital vegetation maps (pixel size = 30 cm) for an area of 4 km2 in the Galilee Mountains, northern Israel. GIS tools were used to produce corresponding maps of grazing regime, topographic indices and other relevant environmental factors. The effects of those factors were quantiﬁed using a multiple regression analyses. Major changes in the vegetation occurred during the period studied (1964–1992); tree cover increased from 2% in 1964 to 41% in 1992, while herbaceous vegetation cover decreased from 56% in 1964 to 24% in 1992. Grazing, topography and initial vegetation cover were found to signiﬁcantly affect present vegetation patterns. Both cattle grazing and goat grazing reduced the rate of increase in tree cover, yet even intensive grazing did not halt the process. Grazing affected also the woody-herbaceous vegetation dynamics, reducing the expansion of woody vegetation. Slope, aspect, and the interaction term between these two factors, signiﬁcantly affected vegetation pattern. Altogether, 56% and 72% of the variability in herbaceous and tree cover, respectively, was explained by the regression models. This study indicates that spatially explicit Mediterranean vegetation dynamics can be predicted with fair accuracy using few biologically important environmental variables.
Keywords: aerial photographs; GIS; landscape ecology; regression model; spatial structure; Vegetation dynamics

Effects of three fungal pathogens on water relations, chlorophyll fluorescence and growth of Quercus suber L - Luque, Jordi; Cohen, Moshe; Save, Robert; Biel, Carmen; Álvarez F., Isabel (Ann. For. Sci., 1999)
Some physiological and growth parameters were studied in cork oak plants inoculated with three pathogenic fungi growth, stomatal conductance, air-leaf temperature and photo- (Botryosphaeria stevensii, Hypoxylon mediterraneum and Phytophthora cinnamomi) in order to understand the effects of the fungal infection. All inoculated fungi induced the reduction of daily stem chemical efficiency. The more aggressive pathogens, B. stevensii ans P. cinnamomi, induced the sharpest decline in all growth and physiological parameters. A sudden decline of all variables was caused by B. stevensii within 6 days after inoculation, followed by a temporary increase in maximum daily shrinkage coinciding with wilting of the plants. The plants inoculated with P. cinnamomi underwent a more gradual decrease in all parameters, whereas H. mediterraneum induced a slight but still significant reduction only in stem growth and shrinkage. Linear variable displacement transducers (LVDT) proved to be a suitable tool to measure some effects of the pathogenesis.
Keywords: Botryosphaeria stevensii; hydric stress; Hypoxylon mediterraneum; LVDT; pathogenic effect; phytophthora cinnamomi

Effects on natural regeneration of woodland in a dehesa system grazed by Avilena-Negra Iberica Breed - Rodriguez, R (Cahiers Options …, 1999)
Effects on concentrated calving against continuous calving and different supplementation levels on cattle in a dehesa system have been studied. In these experimental conditions we considered it necessary to evaluate grazing effectso n natural regeneration of holm oaks (Quercus rotundifoliaa) nd cork oaks (Quercus suber).
Keywords: cattle.; dehesa system; no transhumance exploitation; Overgrazing; regeneration woodland

Egg development and diapause: ecophysiological and genetic basis of phenological polymorphism and adaptation to varied hosts in the green oak tortrix, Tortrix viridana L-(Lepidoptera : Tortricidae) - Du Merle, P (JOURNAL OF INSECT PHYSIOLOGY, 1999)
Experiments concerned 8 tortrix populations associated with varied oak species. They showed that the egg development included a phase of diapause. Completion of embryogenesis at 20 degrees C was used as a criterion for whether diapause was completed. Under semi-natural conditions diapause terminated in late autumn or early winter, then eggs developed continuously, without postdiapause winter quiescence, even in severe cold. The eggs from the populations associated with helm or cork oak completed diapause then hatched later than those from the populations associated with sessile or pubescent oak. Reciprocal crossbreedings confirmed that this phenological polymorphism was genetically determined. Under constant temperatures the physiological state of diapausing eggs, assessed by measuring their cold requirements to complete diapause by exposure to 8 degrees C, varied gradually with increasing age. This diapause development was strongly temperature-dependent. Cold requirements of diapausing eggs were much higher in a late-hatching than in an early-hatching population. This explains the phenological polymorphism of the tortrix: the more eggs need cold, the later they complete diapause in autumn, and the later they hatch in spring. Egg cold requirements varied widely within populations too, which resulted in large variations in the date of diapause end among individuals. The dare of egg hatch was influenced by the temperatures occurring during diapause and postdiapause, but apparently not by photoperiod. (C) 1999 Elsevier Science Ltd. All rights reserved.
Keywords: diapause; egg development; phenological polymorphism; Quercus; Tortrix viridana

Endangered stands of thuriferous juniper in the western Mediterranean basin: ecological status, conservation and management - Gauquelin, Thierry; Bertaudiere, Valerie; Montès, Nicolas (Biodiversity and Conservation, 1999)
Thuriferous juniper is only found in isolated parts of the western Mediterranean: France (Alps, Pyrenees and Corsican highlands), Spain, Algeria and Morocco. These semi-arid mountain stands, where thuriferous juniper trees grow in low-density open woodland, are seriously endangered: (i) In the Atlas mountains, the thuriferous juniper stands are heavily degraded as a result of the intensive wood removal and livestock activity in these densely populated areas. This situation, which will soon become irreversible unless remedial measures are urgently taken, has produced impoverished soils and hillside instability while contributing to desertiﬁcation. (ii) In Spain, although livestock activity and cultivation have strongly reduced areas occupied by Juniperus thurifera, stands are still numerous and, in some regions, show a good regeneration due to conservation measures. (iii) In France, the decline in human and livestock activities over recent decades has led to a recolonization of some of the Juniper stands by pines or oak. A forest management system that enables these original stands to survive and regenerate must be undertaken without delay. The dynamics of evolution of these stands is quite different north and south of the Mediterranean. In both cases, conservation measures are urgently required to protect or rehabilitate these original stands with ﬂoristic, ecological and socio-economic interest.
Keywords: conservation; degradation; Juniperus thurifera; management; Mediterranean basin; thuriferous juniper woodland

Endangered stands of thuriferous juniper in the western Mediterranean basin: ecological status, conservation and management - Gauquelin, Thierry; Bertaudiere, Valerie; Montès, Nicolas (Biodiversity and Conservation, 1999)
Thuriferous juniper is only found in isolated parts of the western Mediterranean: France (Alps, Pyrenees and Corsican highlands), Spain, Algeria and Morocco. These semi-arid mountain stands, where thuriferous juniper trees grow in low-density open woodland, are seriously endangered: (i) In the Atlas mountains, the thuriferous juniper stands are heavily degraded as a result of the intensive wood removal and livestock activity in these densely populated areas. This situation, which will soon become irreversible unless remedial measures are urgently taken, has produced impoverished soils and hillside instability while contributing to desertiﬁcation. (ii) In Spain, although livestock activity and cultivation have strongly reduced areas occupied by Juniperus thurifera, stands are still numerous and, in some regions, show a good regeneration due to conservation measures. (iii) In France, the decline in human and livestock activities over recent decades has led to a recolonization of some of the Juniper stands by pines or oak. A forest management system that enables these original stands to survive and regenerate must be undertaken without delay. The dynamics of evolution of these stands is quite different north and south of the Mediterranean. In both cases, conservation measures are urgently required to protect or rehabilitate these original stands with ﬂoristic, ecological and socio-economic interest.
Keywords: conservation; degradation; Juniperus thurifera; management; Mediterranean basin; thuriferous juniper woodland

Environmental constraints at the edge of a species distribution, the Eurasian badger (Meles meles L.): a biogeographic approach - Virgos, E; Casanovas, J G (JOURNAL OF BIOGEOGRAPHY, 1999)
Aim This paper describes the distribution pattern (occurrence) of badgers (Meles meles L. 1758) in a Mediterranean mountain area of central Spain, in relation to landscape characteristics and climatic data. We test the fit of the badger occurrence pattern to the niche hypothesis predictions. Location We sampled twenty-four survey plots randomly distributed in the mountains of central Spain (Sierra de Guadarrama, Madrid): ten in the north and fourteen in the south slopes. All habitat types and climatic conditions typical of central Spain can be found. Methods The ocurrence of badgers ill the plots were recorded through an exhaustive search of setts and latrines in four different (and evenly spaced) points in each plot. The index of occurrence was made by dividing the number of positive points (badger presence) by the total number of points sampled (four in all plots). Landscape patterns (% type of habitat in each plot) were obtained from detailed maps and climate data from meteorological stations placed in the plot. We analyse the contribution of landscape variables and climate data to explain the differences in badger occurrence through Pearson correlations and fixed one-way ANCOVA with climatic data as fixed factor, vegetation cover as covariates and badger occurrence as response variable. Additionally, we use an one-way ANOVA to check the differences in occurrence between north and south plots with the location of each plot as fixed factor. Results The results indicate that the badger is more abundant in rainy areas of the mountains, and in open landscapes vegetated by ash-tree forests than in closed landscapes vegetated by helm oak forests. In addition, the species is more abundant in the northern plots than in the southern ones. Northern plots were homogeneous areas characterized by their open landscape and wet climate, while southern plots were characterized by their dry climate and closed landscapes. In addition, climate (measured as summer rain) is more determinant than habitat type (holm oak cover) to explain the pattern of badger occurrence. Main conclusions Overall, we consider that the typical Mediterranean landscapes are poor habitats for badgers due to changes in the environmental conditions associated with. concomitant changes in food resources. These data support the niche hypothesis to explain the changes in abundance or occurrence close to the edge of the distribution of species, and in particular, in Palearctic species in the Mediterranean area.
Keywords: Environmental factors; Mediterranean mountains; meles meles; niche hypothesis; species distributions

Environmental constraints at the edge of a species distribution, the Eurasian badger (Meles meles L.): a biogeographic approach - Virgos, E.; Casanovas, J. G. (JOURNAL OF BIOGEOGRAPHY, 1999)
Aim This paper describes the distribution pattern (occurrence) of badgers (Meles meles L. 1758) in a Mediterranean mountain area of central Spain, in relation to landscape characteristics and climatic data. We test the fit of the badger occurrence pattern to the niche hypothesis predictions. Location We sampled twenty-four survey plots randomly distributed in the mountains of central Spain (Sierra de Guadarrama, Madrid): ten in the north and fourteen in the south slopes. All habitat types and climatic conditions typical of central Spain can be found. Methods The ocurrence of badgers ill the plots were recorded through an exhaustive search of setts and latrines in four different (and evenly spaced) points in each plot. The index of occurrence was made by dividing the number of positive points (badger presence) by the total number of points sampled (four in all plots). Landscape patterns (% type of habitat in each plot) were obtained from detailed maps and climate data from meteorological stations placed in the plot. We analyse the contribution of landscape variables and climate data to explain the differences in badger occurrence through Pearson correlations and fixed one-way ANCOVA with climatic data as fixed factor, vegetation cover as covariates and badger occurrence as response variable. Additionally, we use an one-way ANOVA to check the differences in occurrence between north and south plots with the location of each plot as fixed factor. Results The results indicate that the badger is more abundant in rainy areas of the mountains, and in open landscapes vegetated by ash-tree forests than in closed landscapes vegetated by helm oak forests. In addition, the species is more abundant in the northern plots than in the southern ones. Northern plots were homogeneous areas characterized by their open landscape and wet climate, while southern plots were characterized by their dry climate and closed landscapes. In addition, climate (measured as summer rain) is more determinant than habitat type (holm oak cover) to explain the pattern of badger occurrence. Main conclusions Overall, we consider that the typical Mediterranean landscapes are poor habitats for badgers due to changes in the environmental conditions associated with. concomitant changes in food resources. These data support the niche hypothesis to explain the changes in abundance or occurrence close to the edge of the distribution of species, and in particular, in Palearctic species in the Mediterranean area.
The following values have no corresponding Zotero field: pub-location: P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND publisher: BLACKWELL SCIENCE LTD
Keywords: Environmental factors; Mediterranean mountains; meles meles; niche hypothesis; species distributions

Epiphytic lichens and bryophytes of forest ecosystems in Tuscany (Central Italy) - Loppi, Stefano; Bonini, Ilaria; de Dominicis, Vincenzo (Cryptogamie Mycologie, 1999)
The distribution of epiphytic bryophytes and lichens on three species of trees (Quercus ilex, Quercus cerris and Fagus sylvatica, representing the forest ecosystems of central Italy at low, medium and high elevations, respectively) was examined with respect to host specificity and habitat differences. Although most species were host-specific, the results suggested that habitat characteristics are more important than phorophyte properties in determining the distribution of lichens and bryophytes. Factors affecting the diversity of the epiphytic flora were different for lichens and bryophytes. In the case of lichens, climatic parameters and forest monospecificity were important factors, whereas tree cover (i.e. shade) and to a certain extent the number of available trees seemed more important for bryophytes.
Keywords: distribution (voyant); epiphytic bryophytes; epiphytic lichens; forest ecosystems; Host specificity

Epiphytic lichens and bryophytes of forest ecosystems in Tuscany (Central Italy) - Loppi, Stefano; Bonini, Ilaria; de Dominicis, Vincenzo (Cryptogamie Mycologie, 1999)
The distribution of epiphytic bryophytes and lichens on three species of trees (Quercus ilex, Quercus cerris and Fagus sylvatica, representing the forest ecosystems of central Italy at low, medium and high elevations, respectively) was examined with respect to host specificity and habitat differences. Although most species were host-specific, the results suggested that habitat characteristics are more important than phorophyte properties in determining the distribution of lichens and bryophytes. Factors affecting the diversity of the epiphytic flora were different for lichens and bryophytes. In the case of lichens, climatic parameters and forest monospecificity were important factors, whereas tree cover (i.e. shade) and to a certain extent the number of available trees seemed more important for bryophytes.
Keywords: distribution (voyant); epiphytic bryophytes; epiphytic lichens; forest ecosystems; Host specificity

Etiology of oak decline in Spain - Gallego, F J; de Algaba, A Perez; Fernandez-Escobar, R (European Journal of Forest Pathology, 1999)
In different areas of Extremadura, Western Spain, soil samples were taken at the bottom of holm oak (Quercus ilex) trees that were showing decline symptoms. Half of each sample was sterilized, and acorns were sown in both sterilized and nonsterilized soil samples. The resulting seedlings were used as baits for the isolation of fungi. Seedlings growing on the natural, nonsterilized substrate were characterized by having a lower vegetative growth than the ones growing on the sterilized soil samples, and most of them died. Phytophthora dnnamomi was consistently isolated from their roots. Fusarium oxysporum was also isolated as well as different species of Pythium, although to a lesser extent. Pathogenicity tests were performed on holm oak seedlings with five different isolates of P. chinnamomi, with F. oxysporum, Pythium and with a mixture of the three fungi. All the inoculated seedlings with P. chinnamomi developed root rot and grew slowly, and 35.7% of them died up to the end of the experiments. P. chinnamomi was consistently isolated from their roots, indicating that this fungus is the causal agent of holm oak decline. However, F. oxysporum caused similar symptoms on oak seedlings as P. chinnamomi, and was isolated also from the roots, although its frequency was lower than that of. P. cinnamomi.
Keywords: Holm oak; Oak decline; Pathogenicity; Phytophthora cinnamomi (PG)

Etiology of oak decline in Spain - Gallego, F. J.; de Algaba, A. Perez; Fernandez-Escobar, R. (European Journal of Forest Pathology, 1999)
In different areas of Extremadura, Western Spain, soil samples were taken at the bottom of holm oak (Quercus ilex) trees that were showing decline symptoms. Half of each sample was sterilized, and acorns were sown in both sterilized and nonsterilized soil samples. The resulting seedlings were used as baits for the isolation of fungi. Seedlings growing on the natural, nonsterilized substrate were characterized by having a lower vegetative growth than the ones growing on the sterilized soil samples, and most of them died. Phytophthora dnnamomi was consistently isolated from their roots. Fusarium oxysporum was also isolated as well as different species of Pythium, although to a lesser extent. Pathogenicity tests were performed on holm oak seedlings with five different isolates of P. chinnamomi, with F. oxysporum, Pythium and with a mixture of the three fungi. All the inoculated seedlings with P. chinnamomi developed root rot and grew slowly, and 35.7% of them died up to the end of the experiments. P. chinnamomi was consistently isolated from their roots, indicating that this fungus is the causal agent of holm oak decline. However, F. oxysporum caused similar symptoms on oak seedlings as P. chinnamomi, and was isolated also from the roots, although its frequency was lower than that of. P. cinnamomi.
The following values have no corresponding Zotero field: publisher: Blackwell Publishing Ltd
Keywords: Holm oak; Oak decline; Pathogenicity; Phytophthora cinnamomi (PG)

Exploring the relationships between reflectance and anatomical and biochemical properties in Quercus ilex leaves - Ourcival, J M; Joffre, R; Rambal, S (New Phytologist, 1999)
Leaf anatomical parameters such as leaf mass per area (LMA) and biochemical composition can be used as indicators of leaf photosynthetic capacity. The aims of this study are to evaluate the potential of reflectance spectroscopy of fresh leaves for assessing and predicting various parameters, anatomical (LMA and tissue thickness) and biochemical (nitrogen concentration). This paper describes results obtained with fresh leaves of holm oak (Quercus ilex), an evergreen oak that is widely distributed from mesic to xeric habitats in the Mediterranean. Fresh leaves (560) were collected over 3 yr at six different sites, from the top to the bottom of the canopy. The reflectance of each leaf was obtained within 1 h of sampling with an NIRSystems 6500 spectrophotometer over the range 400–2500 nm. LMA was determined for all samples; biochemical and anatomical measurements were conducted over representative subsample populations of 92 and 87 leaves, respectively. Stepwise regression calibrations and partial least squares (PLS) calibrations were developed and compared with different spectral regions and mathematical treatments. Calibration equations had high coefficients of determination (r2 ranging from 0.94 for nitrogen to 0.98 for LMA and tissue thickness). The PLS regressions gave better results than stepwise regressions for all parameters studied. Compared with regressions calculated on raw spectral data, calculations on second derivatives of spectra improved results in all cases. The use of scatter corrections also improved results. These results show that visible and near-infra red reflectance can be used for accurately predicting anatomical parameters and the nitrogen concentration of fresh holm oak leaves. The results support the suggestion that high spectral resolution imaging spectrometry can be a useful tool for assessing functional processes in forest ecosystems.
Keywords: Anatomy; infrared spectroscopy; Leaf mass per area; Quercus ilex; reflectance; Thickness

Factors controlling the emissions of volatile organic acids from leaves of Quercus ilex L.(Holm oak) - Gabriel, R.; Schäfer, L.; Gerlach, C. (Atmospheric Environment, 1999)
Direct emissions and emission of precursor compounds of acetic and formic acid from higher plants are a signiÞcant source of these acids in the atmosphere. To travel from the plant cell to the atmosphere, a gas molecule must Þrst leave the liquid phase and then enter the internal leaf gas phase. The apoplast (cell wall) is the last barrier before the molecule can escape through the stomata. During Þeld experiments we monitored the gas exchange (H 2 O, CO 2 , organic acids) of Quercus ilex L. leaves. The exchange rates of acetic and formic acid under Þeld conditions followed a typical diurnal pattern and ranged between!10 (uptake) and 52 (emission) nmol m~2 leaf area min~1 with the maximum around noon. Growth chamber experiments indicate that the emission is related to the stomatal conductance. We discussed the exchange rate of organic acids between the cell wall and the atmosphere in connection with HenryÕs law, and the physicochemical conditions in the cell wall. The evaluation showed that for apoplastic pH values between 4 and 5, 26Ð130% of the measured acetic acid emission based on leaf area could be predicted. ( 1999 Elsevier Science Ltd. All rights reserved.
Keywords: aba abscisic acid; Gas exchange; organic acids; Quercus ilex

Factors controlling the emissions of volatile organic acids from leaves of Quercus ilex L.(Holm oak) - Gabriel, R; Schafer, L; Gerlach, C (Atmospheric Environment, 1999)
Direct emissions and emission of precursor compounds of acetic and formic acid from higher plants are a signiÞcant source of these acids in the atmosphere. To travel from the plant cell to the atmosphere, a gas molecule must Þrst leave the liquid phase and then enter the internal leaf gas phase. The apoplast (cell wall) is the last barrier before the molecule can escape through the stomata. During Þeld experiments we monitored the gas exchange (H 2 O, CO 2 , organic acids) of Quercus ilex L. leaves. The exchange rates of acetic and formic acid under Þeld conditions followed a typical diurnal pattern and ranged between!10 (uptake) and 52 (emission) nmol m~2 leaf area min~1 with the maximum around noon. Growth chamber experiments indicate that the emission is related to the stomatal conductance. We discussed the exchange rate of organic acids between the cell wall and the atmosphere in connection with HenryÕs law, and the physicochemical conditions in the cell wall. The evaluation showed that for apoplastic pH values between 4 and 5, 26Ð130% of the measured acetic acid emission based on leaf area could be predicted. ( 1999 Elsevier Science Ltd. All rights reserved.
Keywords: aba abscisic acid; Gas exchange; organic acids; Quercus ilex

Fine-resolution Upper Weichselian and Holocene palynological record from Navarrés (Valencia, Spain) and a discussion about factors of Mediterranean forest succession - Carrión, J S; Geel, B Van (Review of Palaeobotany and Palynology, 1999)
A detailed study is presented of the Upper Pleistocene and Holocene pollen sequence of the Navarre´s peat deposit (Valencia, eastern Spain) including non-pollen palynomorphs, Characeae gyrogonites, seeds and charcoal abundance. The study covers the period from ca. 30,900 to 3160 yr B.P. The last glacial vegetation is characterised by Pinus–Artemisia– Ephedra assemblages. This dominance is interrupted between ca. 30,260 and 27,890 yr B.P. by the development of Quercus, Pinus pinaster, deciduous trees and Mediterranean shrubs, suggesting the proximity of glacial refugia and an expansion of their vegetation under inﬂuence of a milder climate. A Younger Dryas signal is noticed by increases of Artemisia and Ephedra around 10,380 yr B.P. There is no immediate response of Quercus to the Late Glacial and Holocene climatic ameliorations and Pinus continues to dominate the landscape until removed at ca. 5930 yr B.P., presumably by severe ﬁre events whose causes are discussed in the light of palynological, anthracological and paleoclimatical data
Keywords: Holocene; navarrés; paleoecology; pollen; quaternary; Spain; vegetation history; younger dryas

Fine-resolution Upper Weichselian and Holocene palynological record from Navarrés (Valencia, Spain) and a discussion about factors of Mediterranean forest succession - Carrión, J. S.; Geel, B. Van (Review of Palaeobotany and Palynology, 1999)
A detailed study is presented of the Upper Pleistocene and Holocene pollen sequence of the Navarre´s peat deposit (Valencia, eastern Spain) including non-pollen palynomorphs, Characeae gyrogonites, seeds and charcoal abundance. The study covers the period from ca. 30,900 to 3160 yr B.P. The last glacial vegetation is characterised by Pinus–Artemisia– Ephedra assemblages. This dominance is interrupted between ca. 30,260 and 27,890 yr B.P. by the development of Quercus, Pinus pinaster, deciduous trees and Mediterranean shrubs, suggesting the proximity of glacial refugia and an expansion of their vegetation under inﬂuence of a milder climate. A Younger Dryas signal is noticed by increases of Artemisia and Ephedra around 10,380 yr B.P. There is no immediate response of Quercus to the Late Glacial and Holocene climatic ameliorations and Pinus continues to dominate the landscape until removed at ca. 5930 yr B.P., presumably by severe ﬁre events whose causes are discussed in the light of palynological, anthracological and paleoclimatical data
Keywords: Holocene; navarrés; paleoecology; pollen; quaternary; Spain; vegetation history; younger dryas

Genetic variation in central and marginal populations of Quercus suber L. - Jimenez, P; Agundez, D; Alia, R; Gil, L (SILVAE GENETICA, 1999)
Eighteen spontaneous populations of cork oak (Quercus suber) from Spain (14), Portugal (1), Morocco (1) and Italy (2), were surveyed at 14 loci from 12 enzyme systems. Percentage of polymorphic loci (64%), mean number of alleles (2.07), and mean expected heterozygosity (0.158) values were within the ranges described for the genus. Populations from the central range of the species and from peripheral areas were evaluated, and differences between these two kinds were assessed. Significant lower diversity (number of alleles and expected heterozygosity) was found for the most isolated and small size populations in contrast to central forests, showing the existence of mechanisms maintaining the levels of diversity even in some ;isolated stands. Interpopulation diversity (F-st) is 3.3%, indicating extensive gene flows or recent postglacial expansion. A possible recent bottleneck is detected in two populations by comparing actual with expected heterozygosity from the number of detected alleles.
Keywords: Genetic Variation; isolation; isozymes; marginal populations.; Quercus suber

Geographical and seasonal influences on the distribution of fungal endophytes in Quercus ilex - Collado, J; Platas, G; GONZÁLEZ, I; Pelaez, F (New Phytologist, 1999)
A systematic survey of the endophytic assemblages of Quercus ilex in central Spain has been performed, with the goal of evaluating the importance of geographical and seasonal factors on these fungal communities. Four sampling sites were selected; one of them was sampled twice, in the spring and the autumn. The collected plant material consisted of bark, twigs and leaves from eight trees per site. Fungal strains were isolated with the use of a surface-sterilization method with sodium hypochlorite. A total of 2921 fungal strains grouped into 149 ‘species’ or morphological types were recovered. The 10 dominant species, with isolation frequencies >1.5%, were Pyrenochaeta sp., Periconiella anamorph of Biscogniauxia mediterranea (De Not.) Kuntze, Pseudonectria sp., Cryptosporiopsis quercina Petrak, Alternaria alternata (Fr:) Keissl., two undetermined coelomycetes, Penicillium funiculosum Thom, Diplodia mutila Fr. apud Mont. and Ascochyta sp. Medians of fungal species per tree were significantly different among the sampled sites. The isolation frequencies of the dominant species, as well as other less frequent species, were significantly dependent on the sampling site. The degree of endophytic infection and the diversity of fungal species were significantly higher in the spring. The frequencies of all dominant species at one of the sites depended significantly on the season, except for C. quercina, Acremonium sclerotigenum (F & V Moreau ex Valenta) Gams. and D. mutila. Cluster analysis of the whole endophytic mycoflora of the sampled trees suggested that the geographical factor affects the endophytic distribution patterns more significantly than the seasonal factor.
Keywords: fungal endophytes; geographical distribution; Quercus ilex; seasonal distribution; Spain

Geographical and seasonal influences on the distribution of fungal endophytes in Quercus ilex - Collado, J.; Platas, G.; GONZÁLEZ, I.; Pelaez, F. (New Phytologist, 1999)
A systematic survey of the endophytic assemblages of Quercus ilex in central Spain has been performed, with the goal of evaluating the importance of geographical and seasonal factors on these fungal communities. Four sampling sites were selected; one of them was sampled twice, in the spring and the autumn. The collected plant material consisted of bark, twigs and leaves from eight trees per site. Fungal strains were isolated with the use of a surface-sterilization method with sodium hypochlorite. A total of 2921 fungal strains grouped into 149 ‘species’ or morphological types were recovered. The 10 dominant species, with isolation frequencies >1.5%, were Pyrenochaeta sp., Periconiella anamorph of Biscogniauxia mediterranea (De Not.) Kuntze, Pseudonectria sp., Cryptosporiopsis quercina Petrak, Alternaria alternata (Fr:) Keissl., two undetermined coelomycetes, Penicillium funiculosum Thom, Diplodia mutila Fr. apud Mont. and Ascochyta sp. Medians of fungal species per tree were significantly different among the sampled sites. The isolation frequencies of the dominant species, as well as other less frequent species, were significantly dependent on the sampling site. The degree of endophytic infection and the diversity of fungal species were significantly higher in the spring. The frequencies of all dominant species at one of the sites depended significantly on the season, except for C. quercina, Acremonium sclerotigenum (F & V Moreau ex Valenta) Gams. and D. mutila. Cluster analysis of the whole endophytic mycoflora of the sampled trees suggested that the geographical factor affects the endophytic distribution patterns more significantly than the seasonal factor.
The following values have no corresponding Zotero field: publisher: Cambridge University Press
Keywords: fungal endophytes; geographical distribution; Quercus ilex; seasonal distribution; Spain

Goats locomotion energy expenditure under range grazing conditions: Seasonal variation - Lachica, M; Somlo, R; Barroso, F G; Boza, J; Prieto, C (JOURNAL OF RANGE MANAGEMENT, 1999)
The estimation of the energy cost of various activities using calorimetric techniques in conjunction with direct field observations can be used to estimate energy expended in the daily activities of free-ranging animals. The objective of this study was to observe and quantify the grazing activities and to estimate the energy expenditure due to locomotion of goats in open range. The study was carried out at `Finca de Bonaya' privately-owned site, which extends over 1,482 ha, located in the Nevada mountain-range, Almeria. The local altitude varies from 1,100 to 2,000 m above sea level. The area has a mediterranean mountain climate, with annual precipitation ranging from 400 to 700 mm and average daily temperatures from 4.7 degrees C in winter to 23.0 degrees C in slimmer. Landscape is characterised by holm oak wood and pine wood, degradation scrubs and hydrophilic grasses communities. The experimental flock grazed on 3 routes during the whole year. The goats were released to graze during the day and then returned to an enclosed shed. The type of goat management was considered as semi-extensive. Direct observation was used to simulate the total distance walked, the vertical ascent or descent, and to quantify other grazing activities. Data on activities on range and distance travelled were taken on 3 days in each season. The energy expenditure of locomotion was calculated from the horizontal and vertical components of travel and the corresponding costs, which had been previously obtained by calorimetry. There was no significant seasonal effect on period devoted to specific activities on range (P>0.05). However, significant changes in the estimated daily energy expenditure and extra energy expenditure due to locomotion of the animals at pasture were found in different seasons (P<0.05). Grazing and walking were the primary activities of goats throughout the study, accounting for 51.7 and 42.0% of the animals' daily period on range, respectively. Daily travelled distances by goats on range fluctuated from 12,777 m in summer to 8,100 m in autumn, with an annual average of 9,954 m, which represents a mean speed of 20.8 m/min calculated over the whole period on range. The mean annual vertical ascent or descent was 500 m. Estimated heat production due to locomotion ranged from 130.9 to 88.5 kJ/kg(0.75) per day in summer and autumn respectively. These values account for an increased metabolizable energy (ME) requirement at pasture above maintenance of 46.6 and 31.6%, respectively, assuming a ME requirement for maintenance of 401 kJ/kg(0.75) per day for the restrained goat.
Keywords: Goats; Grazing; heat production; locomotion

Habitat correlates of European rabbit (Oryctolagus cuniculus) distribution after the spread of RVHD in Cadiz Province, Spain - Fa, John E; Sharples, Colin M; Bell, Diana J (Journal of Zoology, 1999)
European rabbit Oryctolagus cuniculus abundance was evaluated relative to habitat variables within two zones in Cadiz Province (south-east Spain), 2 years after the spread of rabbit viral haemorrhagic disease (RVHD). The study areas were low-lying regions of mixed pasture/agriculture, Mediterranean forest and matorral, west (Zone A) and east (Zone B) of the Sierra de Cadiz mountain chain. A total of 111 sites was selected to sample all existing habitat types. Relative rabbit density in each site was estimated using a pellet count method in one 5062 m transect. Mean pellet densities were 21.05 pellet m -2 in Zone B and signi®cantly lower, 5.85 pellets m -2 in Zone A. Physical variables, such as vegetation characteristics (density, height and patchiness of cover-layer vegetation, etc.), topographical characteristics and human in¯uences, cover-layer vegetation species (woody stemmed shrub species or trees forming dense stands), and ground-layer vegetation species (herbaceous species forming a low-lying layer) were determined within transects. In addition to these variables, soil types, rock type and land form, as well as the presence of aquifers, irrigation, and the proximity of rivers, were determined for each site. Signi®cantly higher pellet densities were found in mixed grassland/matorral and cork oak/matorral than in all other habitats. Pellet density was negatively correlated with density of ground-layer vegetation, while high pellet densities were associated with medium-height ground-layer vegetation (50±100 cm). The presence of Entisols was negatively associated with pellet density. The cover-layer species Pistacia lentiscus, Quercus coccifera, Quercus suber, Opuntia ®cus-indica and the ground-layer grasses all showed positive associations with pellet density, while the ground-layer species Echium gaditana and Scorpiurus vermiculatus were negatively associated with pellet density. Multivariate analyses identi®ed the mixed grassland/matorral and cork oak forest/matorral habitats as explaining most of the variation in pellet density. The height of cover-layer vegetation was negatively associated, while Opuntia and table-and/calcareous sandstone were positively associated, with mixed grassland/matorral. Distance from habitation and human impact were negatively associated and Quercus suber was positively associated with cork oak forest/matorral. Com- parison with previous studies suggest that the low pellet counts in this study represent very low rabbit densities and the population as a whole appears depleted and fragmented
Keywords: habitat; oryctolagus cuniculus; rabbit viral haemorrhagic disease; Spain

Habitat correlates of European rabbit (Oryctolagus cuniculus) distribution after the spread of RVHD in Cadiz Province, Spain - Fa, John E.; Sharples, Colin M.; Bell, Diana J. (Journal of Zoology, 1999)
European rabbit Oryctolagus cuniculus abundance was evaluated relative to habitat variables within two zones in Cadiz Province (south-east Spain), 2 years after the spread of rabbit viral haemorrhagic disease (RVHD). The study areas were low-lying regions of mixed pasture/agriculture, Mediterranean forest and matorral, west (Zone A) and east (Zone B) of the Sierra de Cadiz mountain chain. A total of 111 sites was selected to sample all existing habitat types. Relative rabbit density in each site was estimated using a pellet count method in one 5062 m transect. Mean pellet densities were 21.05 pellet m -2 in Zone B and signi®cantly lower, 5.85 pellets m -2 in Zone A. Physical variables, such as vegetation characteristics (density, height and patchiness of cover-layer vegetation, etc.), topographical characteristics and human in¯uences, cover-layer vegetation species (woody stemmed shrub species or trees forming dense stands), and ground-layer vegetation species (herbaceous species forming a low-lying layer) were determined within transects. In addition to these variables, soil types, rock type and land form, as well as the presence of aquifers, irrigation, and the proximity of rivers, were determined for each site. Signi®cantly higher pellet densities were found in mixed grassland/matorral and cork oak/matorral than in all other habitats. Pellet density was negatively correlated with density of ground-layer vegetation, while high pellet densities were associated with medium-height ground-layer vegetation (50±100 cm). The presence of Entisols was negatively associated with pellet density. The cover-layer species Pistacia lentiscus, Quercus coccifera, Quercus suber, Opuntia ®cus-indica and the ground-layer grasses all showed positive associations with pellet density, while the ground-layer species Echium gaditana and Scorpiurus vermiculatus were negatively associated with pellet density. Multivariate analyses identi®ed the mixed grassland/matorral and cork oak forest/matorral habitats as explaining most of the variation in pellet density. The height of cover-layer vegetation was negatively associated, while Opuntia and table-and/calcareous sandstone were positively associated, with mixed grassland/matorral. Distance from habitation and human impact were negatively associated and Quercus suber was positively associated with cork oak forest/matorral. Com- parison with previous studies suggest that the low pellet counts in this study represent very low rabbit densities and the population as a whole appears depleted and fragmented
Keywords: habitat; oryctolagus cuniculus; rabbit viral haemorrhagic disease; Spain

Hacia la medición de la renta de bienestar del uso múltiple de un bosque - Palacín, P Campos (Investigación agraria. Sistemas y recursos …, 1999)
Este trabajo presenta una nueva metodología de cuentas microeconómicas que permite medir la renta de bienestar sustentable del uso múltiple de los bosques. Se discuten las diferencias conceptuales y de las aplicaciones actuales de la medición del valor añadido generado por el bosque entre los sistemas normalizados de la contabilidad nacional (SCN) y el sistema de cuentas agroforestales (CAF) propuesto. El trabajo ilustra con la aplicación del sistema CAF a una dehesa de alcornoques y encinas de la comarca de Monfragüe (Cáceres) las ventajas del sistema CAF frente al SCN para conocer la contribución total de la dehesa al bienestar de la sociedad considerando tanto los valores económicos de mercado como los ambientales.
Keywords: Bienestar; Bosque; Cuentas; Dehesa; Mercado; Renta; Sustentable

Heavy Metals in Moss and Bark From Urban Area of Florence: A New Cleaness Procedure for Removing Superficial Particulate Matter - Ducceschi, L; Legittimo, P Cellini; Bonzi, L Morassi (Chemistry and Ecology, 1999)
Abstract Hypnum cupressiforme epiphytic moss and tree bark (elm and holm oak) samples have been collected in three sites of the city of Florence in the period 1995?1998. Lead, zinc, copper, and cadmium were determined by differential pulse anodic stripping voltammetry (DPASV) in about 200 samples collected at different heights above ground. A new clean-up procedure by nitrogen jet has been followed and its efficiency has been also verified by electron microscopy (SEM and ESEM techniques). Lead median contents in moss and bark samples fall within the ranges of 0.052?0.86 and 0.20?1.30 ?moles g?1 (dry weight), resulting values for moss and bark are proportional to the vehicular traffic density. the increasing use of lead-free gasoline has not been followed by a decrease of lead moss concentration.
doi: 10.1080/02757549908037642
Keywords: Bark; biomonitoring; environmental scanning electron microscopy (ESEM); Heavy metals; Moss

Heavy Metals in Moss and Bark From Urban Area of Florence: A New Cleaness Procedure for Removing Superficial Particulate Matter - Ducceschi, L.; Legittimo, P. Cellini; Bonzi, L. Morassi (Chemistry and Ecology, 1999)
Abstract Hypnum cupressiforme epiphytic moss and tree bark (elm and holm oak) samples have been collected in three sites of the city of Florence in the period 1995?1998. Lead, zinc, copper, and cadmium were determined by differential pulse anodic stripping voltammetry (DPASV) in about 200 samples collected at different heights above ground. A new clean-up procedure by nitrogen jet has been followed and its efficiency has been also verified by electron microscopy (SEM and ESEM techniques). Lead median contents in moss and bark samples fall within the ranges of 0.052?0.86 and 0.20?1.30 ?moles g?1 (dry weight), resulting values for moss and bark are proportional to the vehicular traffic density. the increasing use of lead-free gasoline has not been followed by a decrease of lead moss concentration.
doi: 10.1080/02757549908037642doi: 10.1080/02757549908037642The following values have no corresponding Zotero field: publisher: Taylor & Francis
Keywords: Bark; biomonitoring; environmental scanning electron microscopy (ESEM); Heavy metals; Moss

Holm oak and holm oak forests: An introduction - Terradas, J (Ecology of Mediterranean Evergreen Oak Forests, 1999)
Why should we study the Mediterranean evergreen forests of holm oak (Quercus ilex L.)? Besides the pursuit of knowledge, two major reasons can be put forward. First, holm oak forests are a dominant type of vegetation in a transition zone between temperate forests, mostly dominated by deciduous trees and the scrublands (maquis, chaparral, phrygana, etc.) that herald the tropical regions. In this transition zone, plants have had to cope with a selective pressure resulting from a double stress - winter cold and summer drought - that has determined their morphological and ecophysiological evolutive responses. One of our aims is to provide an insight into the features of holm oak as related to environmental factors and in comparison with other tree types (broadleaved deciduous hardwoods, needle-leafed conifers)
APS
Keywords: Geral; Holm oak; Mediterranean; Quercus ilex

The Holocene at Lac de Creno, Corsica, France: a key site for the whole island - REILLE, M; Gamisans, J; Andrieu-Ponel, V; De Beaulieu, J.-L. (New Phytologist, 1999)
Two Holocene lake sequences from Lac de Creno, Corsica were analysed on the basis of 119 pollen spectra and with the support of 13 14C-calibrated dates. The lower part of one of these sequences, corresponding to the late- glacial period, has been published previously. The first third of the Post-glacial is characterized by very particular forest dynamics, namely the absence of a role for deciduous Quercus and Corylus, the presence of mesophilous vegetation types dominated by Taxus, and the major forest role of Erica arborea at lower and mean altitude. At about 7440 cal BP, the occurrence of a major anthropogenic action brought about significant changes in the vegetation, notably an increase of deciduous Quercus and the expansion of Quercus ilex. Later, three major human-induced events are identified: the first, at about 2290 cal BP, is the cause of a short local expansion of Abies; the second, at about 1150 cal BP, is the degradation of deciduous forests to the benefit of Fagus; the third, at about 310 cal BP, corresponds to the disappearance of Fagus and its replacement by Pinus. Pollen data indicate that Q. ilex, Abies and Fagus are not indigenous in Corsica but spread there during the Postglacial ; this probably took place at about 6980 cal BP for Q. ilex.
Keywords: Corsica; glacial vegetation; Holocene; pollen spectra; vegetation history

Improving the use of lichens as biomonitors of atmospheric metal pollution. - Branquinho, C; Catarino, F; Brown, D H; Pereira, M J; Soares, A (The Science of the total environment, 1999)
The data reported on this study supported the hypothesis that the absence of the lichen Ramalina fastigiata near a copper mine site located on the south of Portugal was related to toxic levels of Cu-dust near the centre of the mine. Lichen biodiversity reflected the impact of the copper-mine dust emissions which were more widespread towards the east, correlated with wind direction and frequency. The chemical analysis of R. fastigiata collected at different distances and in different directions from the mine showed that Cu, K and Mg were derived from the centre of the mine site, confirming thus as the major source of atmospheric dust. Total inhibition of PSII photochemical reactions occurred in R. fastigiata both under field and controlled conditions, when intracellular Cu concentrations exceeded a threshold of approximately 2.0 mumol g-1. No samples of this species were found under field conditions beyond the Cu threshold. Thus, the fluorescence parameter Fv/Fm proved to be a good estimator of the survival capacity of R. fastigiata under field conditions and thus a useful parameter in determining the sensitivity of the lichens (photobiont) to Cu pollution. The intracellular location of Cu allowed an explanation of the physiological changes and the survival of the species in the surroundings of the copper-mine.
Keywords: Atmospheric dust pollution; Cellular location of Cu; chlorophyll fluorescence; Cu-mine; Fv Fm; Intracellular Cu; K and Mg; Lichen biodiversity; lichens; Ramalina fastigiata

Improving the use of lichens as biomonitors of atmospheric metal pollution. - Branquinho, C.; Catarino, F.; Brown, D. H.; Pereira, M. J.; Soares, A. (The Science of the total environment, 1999)
The data reported on this study supported the hypothesis that the absence of the lichen Ramalina fastigiata near a copper mine site located on the south of Portugal was related to toxic levels of Cu-dust near the centre of the mine. Lichen biodiversity reflected the impact of the copper-mine dust emissions which were more widespread towards the east, correlated with wind direction and frequency. The chemical analysis of R. fastigiata collected at different distances and in different directions from the mine showed that Cu, K and Mg were derived from the centre of the mine site, confirming thus as the major source of atmospheric dust. Total inhibition of PSII photochemical reactions occurred in R. fastigiata both under field and controlled conditions, when intracellular Cu concentrations exceeded a threshold of approximately 2.0 mumol g-1. No samples of this species were found under field conditions beyond the Cu threshold. Thus, the fluorescence parameter Fv/Fm proved to be a good estimator of the survival capacity of R. fastigiata under field conditions and thus a useful parameter in determining the sensitivity of the lichens (photobiont) to Cu pollution. The intracellular location of Cu allowed an explanation of the physiological changes and the survival of the species in the surroundings of the copper-mine.
The following values have no corresponding Zotero field: accession-num: 10474262
Keywords: Atmospheric dust pollution; Cellular location of Cu; chlorophyll fluorescence; Cu-mine; Fv Fm; Intracellular Cu; K and Mg; Lichen biodiversity; lichens; Ramalina fastigiata

In vitro cold storage of cork oak shoot cultures - Romano, Anabela; Martins-Loução, M a (Plant cell, tissue and organ culture, 1999)
A simple system for in vitro conservation of cork oak shoot cultures (Quercus suber L.) is described. Cultures were stored in vitro on multiplication medium at 51 C without an intervening subculture for two years. The viability, multiplication rate and shoot elongation were evaluated after storage under dark and light conditions. Culture viability was negatively affected by light. In contrast, 50% of cultures survived after two years of cold storage in the dark. Multiplication rate of dark-stored cultures was similar to the controls, and shoot elongation was signiﬁcantly higher. Although the assessment of multiplication rate/shoot elongation is done at the end of the ﬁrst multiplication cycle, we observed that at least in some species such as Quercus suber, it is advisable to study the responsiveness of cultures during the ﬁrst three multiplication cycles following storage. The rooting capacity of shoots produced from dark-stored cultures was similar to non-stored controls. Cultures stored for 6, 12 or 24 months without subculture have similar responsiveness as the ones subcultured monthly. The storage of cultures at 5 C in the dark appears to be a promising technique for medium-term conservation of cork oak germplasm.
Keywords: in vitro conservation; Quercus suber; shoot proliferation; woody species

Influence of farming activities in the Iberian Peninsula on the winter habitat use of common crane ( Grus grus) in areas of its traditional migratory routes - Guzmán, J M S; García, A S (Agriculture, ecosystems &…, 1999)
Farming activities can in¯uence bird habitat and wintering patterns. Changes in the wintering habitat use of common crane (Grus grus) were related to changes in land use on this species' traditional migration route in the Western Palaearctics. The study was conducted in the Orellana area (Extremadura, SW Spain), the most important wintering area on this route, where the continued availability of natural food resources (acorns, bulbs, invertebrates) represents a more balanced diet than agricultural resources alone. The presence of crops such as corn (Zea mays L.) is, however, not a critical factor in the area, since the two types of resources, natural and agricultural, are available in the same period of time. The increase in area dedicated to irrigated crops, especially rice (Oriza sp.), affected the growth in the numbers of wintering cranes in the Orellana area. In the past the peak wintering period was in December and was positively correlated to acorn production, whereas the peak period is now in January±February, coinciding with the use of rice-®eld stubble as feeding places. Dehesas (Mediteranean scrub), cultivated or not, may replace rice-®eld stubble as feeding places. The existence of intensive farming activity in combination with traditional land-uses is suggested to be the cause of these changes. #
Keywords: Common Crane; g. grus; land use; modification; population increase; southwestern Spain; traditional area; wintering pattern

Influence of increased atmospheric CO2 concentration on quality of plant material and litter decomposition - Coûteaux, Marie-Madeleine; Kurz, Cathy; Bottner, Pierre; Raschi, Antonio (Tree Physiology, 1999)
Nitrogen (N) and lignin concentrations in plant tissues and litter of plants grown in greenhouses or open-top chambers in elevated atmospheric CO2 concentration were compared with those of plants grown in ambient air in short-term studies. We also compared the N concentration of plant material of Quercus ilex L. and Q. pubescens Willd. growing in the vicinity of natural CO2-springs with that of the same species growing at a control site. In the short-term studies, elevated CO2 caused significant decreases in tissue N concentration and the extent of the decrease varied with species. Nitrogen amendment of the soil lessened the CO2-enrichment effect. Lignin concentration was modified by elevated CO2 and the effect was species specific, but no general positive or negative trend was evident. A comparison of trees growing under natural conditions near a natural CO2-spring and at a control site revealed no site differences in N concentration of the plant material. A comparison of published results on decomposition rates of litter produced in elevated atmospheric CO2 and in ambient air indicated that CO2 enrichment can cause both enhancements and decreases of carbon mineralization. We conclude that (1) long-term responses to elevated CO2 could differ from the results obtained from short-term studies and that (2) biodiversity could be an important factor altering the sign of the feedback on atmospheric CO2 concentration. We also discuss the implications of our finding of a long-term, inhibitory effect of the initial N concentration of litter on the decomposition rate of litter and its consequence on ecosystem feedback.
10.1093/treephys/19.4-5.301
Keywords: Biodiversity; Carbon dioxide; Global change; lignin content; nitrogen content

Influence of increased atmospheric CO2 concentration on quality of plant material and litter decomposition - Coûteaux, Marie-Madeleine; Kurz, Cathy; Bottner, Pierre; Raschi, Antonio (Tree Physiology, 1999)
Nitrogen (N) and lignin concentrations in plant tissues and litter of plants grown in greenhouses or open-top chambers in elevated atmospheric CO2 concentration were compared with those of plants grown in ambient air in short-term studies. We also compared the N concentration of plant material of Quercus ilex L. and Q. pubescens Willd. growing in the vicinity of natural CO2-springs with that of the same species growing at a control site. In the short-term studies, elevated CO2 caused significant decreases in tissue N concentration and the extent of the decrease varied with species. Nitrogen amendment of the soil lessened the CO2-enrichment effect. Lignin concentration was modified by elevated CO2 and the effect was species specific, but no general positive or negative trend was evident. A comparison of trees growing under natural conditions near a natural CO2-spring and at a control site revealed no site differences in N concentration of the plant material. A comparison of published results on decomposition rates of litter produced in elevated atmospheric CO2 and in ambient air indicated that CO2 enrichment can cause both enhancements and decreases of carbon mineralization. We conclude that (1) long-term responses to elevated CO2 could differ from the results obtained from short-term studies and that (2) biodiversity could be an important factor altering the sign of the feedback on atmospheric CO2 concentration. We also discuss the implications of our finding of a long-term, inhibitory effect of the initial N concentration of litter on the decomposition rate of litter and its consequence on ecosystem feedback.
10.1093/treephys/19.4-5.30110.1093/treephys/19.4-5.301
Keywords: Biodiversity; Carbon dioxide; Global change; lignin content; nitrogen content

The influence of Pinus radiata, Quercus suber, and improved pasture on soil chemical properties - Noble, A D; Little, I P; Randall, P J (AUSTRALIAN JOURNAL OF SOIL RESEARCH, 1999)
Soil acidification and related land degradation issues are assuming increasing importance in Australia and challenging the concept of sustainability of current land management systems. In this study, the impacts of tree plantations of 2 species and permanent pasture on soil chemical properties are compared. Soil samples were collected from the top 50 cm (0-5, 5-10, 10-15, 15-20, 20-30, and 30-50 cm depths) from 3 adjacent sites carrying pasture and monocultures of Pinus radiata (radiata pine) and Quercus suber (cork oak) on a deep-surfaced yellow podzolic soil, and differences in soil pH and other soil chemical properties were examined. In the surface 0-5 cm, pH was similar at all 3 sites. Below that depth, soil pH was significantly lower and exchangeable Al greater under the cork oak stand than at the other 2 sites. Consistent with a decrease in soil pH there was significantly less exchangeable Ca under cork oak. Also, less clay was observed under the cork oak stand and this is taken as evidence of the degradational impact of soil acidification. An estimate of Ca in the top 50 cm of the soil implies considerable loss of Ca under oak, probably by leaching and loss of litter down the slope. Evidence is presented to show that there has been more Fe and Al movement under oak than under pasture and pine, this being ascribed in part to the greater Al and Fe mobilising capacity of the water-soluble component extracted from freshly fallen leaf litter of oak. The Fe and Al composition of the oxalate extract from concretionary material at 10-30 cm under oak is consistent with a process similar to podzolisation. Pseudogleying of Fe and Al may have accompanied the leaching of bases from the system and a reduction of pH.
Keywords: Acidification; clay cont; exchangeable cations; pH

INFORMACIÓN ACERCA DE LA PRESENCIA DE ALCORNOQUE ( Quercus suber L .) EN LA PROVINCIA DE GUADALAJARA - SERRADA HIERRO, R; García Viñas, J I (Investigación agraria. Sistemas y recursos forestales, 1999)
The paper gathers information on the so believed only natural presence of cork oak (Quercus suber L.) in the province of Guadalajara (Central Spain). It is the extremest eastern location of that species in the southern face of the Central Range of Mountains. The most important botanical, ecological and dasometrical aspects of the stand are described. An ecological homologation of the stand, based on Allué Andrade’s work, has also been carried out.
Keywords: Cork oak; Guadalajara; Quercus suber

Interactive effects of nitrogen and phosphorus on the acclimation potential of foliage photosynthetic properties of cork oak, Quercus suber, to elevated atmospheric CO2 concentrations - Niinemets, Ü; Tenhunen, J D; Canta, N R; Chaves, M M; Faria, T; Pereira, J S; Reynolds, J F (Global Change Biology, 1999)
Leaf gas-exchange and chemical composition were investigated in seedlings of Quercus suber L. grown for 21 months either at elevated (700 μmol mol–1) or normal (350 μmol mol–1) ambient atmospheric CO2 concentrations, [CO2], in a sandy nutrient-poor soil with either ‘high’ N (0.3 mol N m–3 in the irrigation solution) or with ‘low’ N (0.05 mol N m–3) and with a constant suboptimal concentration of the other macro- and micronutrients. Although elevated [CO2] yielded the greatest total plant biomass in ‘high’ nitrogen treatment, it resulted in lower leaf nutrient concentrations in all cases, independent of the nutrient addition regime, and in greater nonstructural carbohydrate concentrations. By contrast, nitrogen treatment did not affect foliar N concentrations, but resulted in lower phosphorus concentrations, suggesting that under lower N, P use-efficiency in foliar biomass production was lower. Phosphorus deficiency was evident in all treatments, as photosynthesis became CO2 insensitive at intercellular CO2 concentrations larger than ≈ 300 μmol mol–1, and net assimilation rates measured at an ambient [CO2] of 350 μmol mol–1 or at 700 μmol mol–1 were not significantly different. Moreover, there was a positive correlation of foliar P with maximum Rubisco (Ribulose-1,5-bisphosphate carboxylase/oxygenase) carboxylase activity (Vcmax), which potentially limits photosynthesis at low [CO2], and the capacities of photosynthetic electron transport (Jmax) and phosphate utilization (Pmax), which are potentially limiting at high [CO2]. None of these potential limits was correlated with foliar nitrogen concentration, indicating that photosynthetic N use-efficiency was directly dependent on foliar P availability. Though the tendencies were towards lower capacities of potential limitations of photosynthesis in high [CO2] grown specimens, the effects were statistically insignificant, because of (i) large within-treatment variability related to foliar P, and (ii) small decreases in P/N ratio with increasing [CO2], resulting in balanced changes in other foliar compounds potentially limiting carbon acquisition. The results of the current study indicate that under P-deficiency, the down-regulation of excess biochemical capacities proceeds in a similar manner in leaves grown under normal and elevated [CO2], and also that foliar P/N ratios for optimum photosynthesis are likely to increase with increasing growth CO2 concentrations. Symbols: A, net assimilation rate (μmol m–2 s–1); Amax, light-saturated A (μmol m–2 s–1); α, initial quantum yield at saturating [CO2] and for an incident Q (mol mol–1); [CO2], atmospheric CO2 concentration (μmol mol–1); Ci, intercellular CO2 concentration (μmol mol–1); Ca, CO2 concentration in the gas-exchange cuvette (μmol mol–1); FB, fraction of leaf N in ‘photoenergetics’; FL, fraction of leaf N in light harvesting; FR, fraction of leaf N in Rubisco; Γ*, CO2 compensation concentration in the absence of Rd (μmol mol–1); Jmax*, capacity for photosynthetic electron transport; Jmc, capacity for photosynthetic electron transport per unit cytochrome f (mol e–[mol cyt f]–1 s–1); Kc, Michaelis-Menten constant for carboxylation (μmol mol–1); Ko, Michaelis-Menten constant for oxygenation (mmol mol–1); MA, leaf dry mass per area (g m–2); O, intercellular oxygen concentration (mmol mol–1); [Pi], concentration of inorganic phosphate (mM); Pmax*, capacity for phosphate utilization; Q, photosynthetically active quantum flux density (μmol m–2 s–1); Rd*, day respiration (CO2 evolution from nonphotorespiratory processes continuing in the light); Rubisco, ribulose-1,5-bisphosphate carboxylase/oxygenase; RUBP, ribulose-1,5-bisphosphate; Tl, leaf temperature (°C); UTPU*, rate of triose phosphate utilization; Vcmax*, maximum Rubisco carboxylase activity; Vcr, specific activity of Rubisco (μmol CO2[g Rubisco]–1 s–1] *given in either μmol m–2 s–1 or in μmol g–1 s–1 as described in the text.
Keywords: nitrogen; nutrient imbalances; phosphate limitation; phosphorus nutrition; photosynthetic electron transport; Rubisco

Inventorying emissions from nature in Europe - Simpson, D; Winiwarter, W; Borjesson, G; Cinderby, S; Ferreiro, A; Guenther, A; Hewitt, C N; Janson, R; Khalil, M A K; Owen, S; Pierce, T E; Puxbaum, H; et al. (JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 1999)
As part of the work of the Economic Commission for Europe of the United Nations Task Force on Emission Inventories, a new set of guidelines has been developed for assessing the emissions of sulphur, nitrogen oxides, NH,, CH,, and nonmethane volatile organic compounds (NMVOC) from biogenic and other natural sources in Europe. This paper gives the background to these guidelines, describes the sources, and gives our recommended methodologies for estimating emissions. We have assembled land use and other statistics from European or national compilations and present emission estimates for the various natural/biogenic source categories based on these. Total emissions from nature derived here amount to similar to 1.1 Tg S yr(-1), 6-8 Tg CH4 yr(-1), 70 Gg NH3 (as N) yr(-1), and 13 Tg NMVOC yr(-1). Estimates of biogenic NOx emissions cover a wide range, from 140 to 1500 Gg NOx (as N) yr(-1). In terms of relative contribution to total European emissions for different pollutants, then NMVOC from forests and vegetation are clearly the most important emissions source. Biogenic NOx emissions (although heavily influenced by nitrogen inputs from anthropogenic activities) are very important if the higher estimates are reliable. CH, from wetlands and sulphur from volcanoes are also significant emissions in the European budgets. On a global scale, European biogenic emissions are not significant, a consequence of the climate and size (7% of global land area) of Europe and of the destruction of natural ecosystems since prehistoric times. However, for assessing local budgets and for photochemical oxidant modeling, natural/biogenic emissions can play an important role. The most important contributor in this regard is undoubtedly forest VOC emissions, although this paper also indicates that NMVOC emissions from nonforested areas also need to be further evaluated. This paper was originally conceived as a contribution to the collection of papers arising as a result of the Workshop on Biogenic Hydrocarbons in the Atmospheric Boundary Layer, August 24-27, 1997. (Several papers arising from this workshop have been published in Journal of Geophysical Research, 103(D19) 1998.).
APS
Keywords: Emissions; land use; NOx; Volatile Organic Compounds

Laccase activity of forest litter - Criquet, S.; Tagger, S.; Vogt, G. (Soil Biology and Biochemistry, 1999)
Laccases are blue-copper enzymatic proteins involved in the transformation of polyphenolic compounds, such as lignin, into forest litter. A method to measure their activity was developed using an evergreen oak litter as a model system. We considered factors that aect the extraction of these enzymes and the measurement of their activity. The factors studied included powdering of the leaves, adding polyvinylpolypyrrolidone or Tween 80, adsorption of enzymes on centrifugation pellets, concentration of the extracts, nature and molarity of the extraction solvent, amount of powdered leaves used for enzymatic extraction, extraction time, pH, and temperature during the measurement of the activity
Keywords: Extraction; laccase; litter

Laccase activity of forest litter - Criquet, S; Tagger, S; Vogt, G (Soil Biology and Biochemistry, 1999)
Laccases are blue-copper enzymatic proteins involved in the transformation of polyphenolic compounds, such as lignin, into forest litter. A method to measure their activity was developed using an evergreen oak litter as a model system. We considered factors that aect the extraction of these enzymes and the measurement of their activity. The factors studied included powdering of the leaves, adding polyvinylpolypyrrolidone or Tween 80, adsorption of enzymes on centrifugation pellets, concentration of the extracts, nature and molarity of the extraction solvent, amount of powdered leaves used for enzymatic extraction, extraction time, pH, and temperature during the measurement of the activity
Keywords: Extraction; laccase; litter

Late Pleistocene and Holocene pollen stratigraphy at Lago di Vico, central Italy - Magri, Donatella; Sadori, Laura (Vegetation history and archaeobotany, 1999)
A new pollen record from Lago di Vico (core V1) provides fundamental new information towards re- construction of flora and vegetation history in central Italy during the last 90 000 years. The chronological framework is secured by seventeen AMS 14C dates, one 4°Ar/39Ar date and tephra analyses. At the base of the pol- len record, i.e. shortly after the 4°Ar/39Ar date 87 000+ 7000 B.P., three phases with significant expansion of trees are recorded in close succession. These forest phases, which stratigraphically correspond to St Ger- main II (and Ognon?) and precede pleniglacial steppe vegetation, are designated by the local names Etruria I, Etruria II and Etruria III. During the pleniglacial, a number of fluctuations of angiosperm mesophilous trees suggest the presence of tree refugia in the area. The low- est pollen concentration values are recorded at ca. 22 000 B.P. which corresponds with other pollen records from the region. The late-glacial is characterized by an expansion in the arboreal pollen curves that is less pro- nounced, however, than in other pollen profiles from Italy. The Holocene part of the profile is consistently dominated by deciduous oak pollen. No major changes in arboreal pollen composition are recorded but several marked and sudden declines of the tree pollen concentra- tion suggest that the forest cover underwent dramatic changes. Clear evidence for human impact is recorded only when cultivated crops became important which dates to ca. 26304-95 B.P.
Keywords: Central Italy; Crater lake; Holocene; Late Pleistocene; Pollen analysis

Leaf anatomy, inclination, and gas exchange relationships in evergreen sclerophyllous and drought semideciduous shrub species - Gratani, L; Bombelli, A (PHOTOSYNTHETICA, 1999)
There are significant differences in leaf life-span among evergreen sclerophyllous species and drought semideciduous species growing in the Mediterranean maquis. Cistus incanus, which has a leaf life-span of four-eight months, was characterised by the highest net photosynthetic rates (PN). while Quercus ilex and Phillyrea latifolia, which maintain their leaves two-three and two-four years, respectively, had a lower PN- The longer leaf life-span of the two evergreen sclerophyllous species may be justified to cover the high production costs of leaf protective structures such as cuticle, hairs, and sclereids: cuticle and hairs screen radiation penetrating into the more sensitive tissues, and sclereids have a light-guiding function. Q. ilex and P. latifolia have the highest leaf mass/area ratio (LMA = 209 g m(-2)) and a mesophyll leaf density (2065 cells per mm(2) of leaf cross section area) about two times higher than C. incanus. In the typical evergreen sclerophyllous species the steepest leaf inclination (alpha = 56 degrees) reduces 42% of radiation absorption, resulting in a reduced physiological stress at leaf level, particularly in summer. C. incanus, because of its low leaf life-span, requires a lower leaf investment in leaf protective structures. It exhibits a drastic reduction of winter leaves just before summer drought, replacing them with smaller folded leaves. The lower leaf inclination (alpha = 44 degrees) and the lower LMA (119 g m(-2)) of C. incanus complement photosynthetic performance. Water use efficiency (WUE) showed the same trend in Q. ilex, P. latifolia, and C. incanus, decreasing 60% from spring to summer, due to the combined effects of decreased CO2 uptake and increased transpirational water loss.
Keywords: cistus incanus; leaf inclination; leaf life-span; leaf mass/area ratio; leaf thickness; net photosynthetic rate; phillyrea latifolia; Quercus ilex; transpiration rate

Les grandes structures de végétation en région méditerranéenne: facteurs déterminants dans leur mise en place post-glaciaire - Quezel, P (Geobios, 1999)
The present-day large vegetation units, taking into account their historical value, can, at least partly, be compared with those which have taken place since the end of the Wiirm. The present-day pre-steppic forests, pre- forest units and actual forests enable us to understand: the progressive evolution of the woody vegetation, at least up to the Atlantic, according to the global climatic changes; its regressive evolution in connexion with the increasing anthropic pressure during the following periods. This anthropic pressure, nearly stabilised at the end of the last cen- tury, has been getting weaker in most of the north mediterranean countries, inducing a clear biological revival, whe- reas, in the southern ones, man's action goes on intensifying, due to an uncontrolled increase in population. The pro- blem set by the steppes, matorrals and grasslands has also been taken into consideration but historical data are often too fewer to allow an accurate reconstruction. The present-day dynamism of these formations enables us to understand that their spreading has been and nowadays still remains under the direct influence of man's action, particularly by the way of voluntary fires, grazing and land-clearings.
Keywords: anthropic perturbations; bioclimatic signification; Mediterranean vegetation; origin; post-glacial organisation

Levels of bioelements and their relation to the ruminants ' needs in the most important pasture-plant species of the wooded dehesa ( grazing-land ) in the south-west of Spain - Olea, L; Viguera, F J (Dynamics and sustainability of Mediterranean pastoral systems . CIHEAM, (Cahiers Options Méditerranéennes; n. 39), 1999)
- The Trifolium subterraneum and Orithopus compressus species, together are considered the most important pasture plants (pratenses) with the gramineae group of the wooded 'dehesa' of Edremadura. In the present paper 5 representative "dehesas" (pasture lands) of the south-west of the province of Badajoz (200,000 ha) are studied over a period of two agricultural years (1 993-94 and 94-95). Soils and plants were analysed every fortnight approximately, from Autumn until the end of Spring. Samples of plants from the different plots were taken to check the proportions of N, P, K, Ca and Mg. Climatologically two different weather conditions were studied, a year of almost average rainfall and another of extreme drought. The minimum values for these 5 elements were revised. The Nitrogen proportion in both leguminous species was above the required minimum level (even in dry grass), for the ruminant feeding (over 1.5% and up to 3.5% in January and February), whereas there was a deficiency of Nitrogen in the gramineae group from April on. Regarding Phosphorus, as the plant becomes mature a decrease is noted, which was stressed in the final months of the cycle; all the dehesas studied except Manpolín reached lower rates than the minimum required (0.20%). The potassium evolved in a similar way that of P, although deficiencies (minimum 0.60%) arose only in Campos de Oliva. Its behaviour was similar in both years. Calcium had a similar behaviour in all the dehesas studied along the vegetative cycle. It was always above the minimum level (0.30%) in the gramineae from April on in both years. Magensium results were similar to those of Calcium
Keywords: annual pasture plants; Dehesa; grass quality; mediterranean pasture

Life-cycles and biological features of eggs predators of Lymantria dispar (Lepidoptera : Lymantriidae) in the Mamora cork oak forest, Morocco - Villemant, C; Andrei-Ruiz, M C (EUROPEAN JOURNAL OF ENTOMOLOGY, 1999)
The gypsy moth oophagous predator guild in the Mamora forest is an assemblage of many species whose succession in egg masses enhances the exploitation of this food source. Life history, biological Features and trophic capacities of predator species are described from field observations and laboratory rearing. Extreme diversity of diets, capacity to resist prolonged fasting and extended larval development with extra-instars enable them to survive on the cork oak when gypsy moth egg masses are absent. The 1986-1990 gypsy moth outbreak occurred in a forest part where unhealthy cork oaks are common. by providing abundant shelter for numerous arthropods these trees are beneficial to the oophagous predators which find there various and abundant food sources. This probably explains why egg predator activity in the infested area rapidly increased so that the pest outbreak collapsed.
Keywords: allotrophic capacity; Dermestidae; egg predation; life-cycle; Lymantria dispar; Lymantriidae; Morocco; Pyralidae; Quercus suber; Trogossitidae

Líquenes y hongos liquenícolas epífitos de Quercus ilex L., poco conocidos en encinares de Cataluña (España) - Longán, Angels; Gómez-Bolea, Antonio; Biologia, Dep; Unitat, Vegetal; Biologia, Fac; Barcelona, Unív (Cryptogamie Mycologie, 1999)
We present here 13 species of lichens and 3 of lichenicolous fungi found on Quercus ilex L. in evergreen oak forests of Catalonia. Leptogium coralloideum (Meyen & Flotow) Vainio, Scoliciosporum gallurae Vězda & Poelt, Abrothallus microspermus Tul. are new reports for Spain, and nine more species are new for the flora of Catalonia. For each one of them, a brief morphological characterisation, its distribution in Europe and in the Iberian Peninsula, and its autoecology are given.
Keywords: Catalonia; epiphytes; lichens; Quercus ilex

Líquenes y hongos liquenícolas epífitos de Quercus ilex L., poco conocidos en encinares de Cataluña (España) - Longán, Angels; Gómez-Bolea, Antonio; Biologia, Dep; Unitat, Vegetal; Biologia, Fac; Barcelona, Unív (Cryptogamie Mycologie, 1999)
We present here 13 species of lichens and 3 of lichenicolous fungi found on Quercus ilex L. in evergreen oak forests of Catalonia. Leptogium coralloideum (Meyen & Flotow) Vainio, Scoliciosporum gallurae Vězda & Poelt, Abrothallus microspermus Tul. are new reports for Spain, and nine more species are new for the flora of Catalonia. For each one of them, a brief morphological characterisation, its distribution in Europe and in the Iberian Peninsula, and its autoecology are given.
Keywords: Catalonia; epiphytes; lichens; Quercus ilex

Low molecular weight phenols in cork stoppers - Pena-Neira, A; Hernández, T; GARCIA-VALLEJO, M C; Cadahía, E; de Simon, B F; Suarez, J A (AMERICAN JOURNAL OF ENOLOGY AND VITICULTURE, 1999)
In this work, we study the low molecular-weight polyphenols in cork stoppers obtained from commercial wine bottles and in samples taken at five stages of the cork stopper manufacturing process. The phenolic compounds (acids, aldehydes, and coumarins) were analyzed by high pressure liquid chromatography with photodiode array detector. The results were studied by statistical methods in order to determine the relationship among these compounds and their variability throughout the industrial processing. Discriminant analysis showed that the phenolic composition allows differentiation of each stage in the manufacture of cork stoppers and the different provenances of stoppers obtained from commercial wine bottles. The results showed wide variations in phenolic content among cork stoppers within each region and each winery.
Keywords: Cork; phenolic compounds; stopper manufacturing

Low molecular-weight phenolic compounds in natural and agglomerated cork stoppers - Pena-Neira, A; BartolomÉ, B; Cadahía, E; Hernández, T; Garcia-Vallejo, C; GONZALEZ-ADRADOS, J R; Suarez-Lepe, J A (SCIENCES DES ALIMENTS, 1999)
The low molecular-weight phenolic compounds in cork stoppers used for the closure of wine bottles are studied. Different phenolic acids (gallic, protocatechuic, vanillic, caffeic, ferulic and ellagic), aldehydes (protocatechuic, p-hydroxybenzoic, vanillin, ethylvanillin and coniferilic), and coumarins (aesculetin and scopoletin) were determined in natural cork stoppers (untreated and chlorine-bleached) and in agglomerated cork stoppers (unbleached and peroxide-bleached). The ketone 2,3-dihydroxy-1-guaiacylpropan-1-one and four ellagic-acid-type tannins were detected in natural stoppers. The amount of most of the phenolic compounds studied was higher in the natural cork stoppers than in agglomerated stoppers. In natural cork stoppers, an Increase in the content of caffeic and ferulic acids and vanillin was observed after chlorine bleaching. In agglomerated stoppers however, peroxide bleaching produced a decrease in the content of these same compounds.
Keywords: Cork; low molecular-weight phenolic; Stopper; stopper treatment

Mediterranean vegetation dynamics: modelling problems and functional types - Pausas, J G (Plant Ecology, 1999)
Gap models have been applied to a wide range of ecosystems, mainly temperate and boreal forests, but rarely have such models been applied to Mediterranean ecosystems. In the present review we address some problems of gap models for predicting the long-term dynamics of Mediterranean ecosystems, and we suggest plant functional types suitable for modelling based on responses to disturbance. Most gap models do not take into account different life forms, interactions with ﬁre (e.g., resprouting and stimulation of the germination), and underground structures. Long term human impact on Mediterranean ecosystems has made a signiﬁcant impact on the current landscapes. That intense land use, involving long-lived slow-growing species, has had long-term consequences. It is not possible to understand Mediterranean vegetation and to validate any model without considering these factors. The lack of data for Mediterranean species may be overcome by taking into account correlations of traits and trade-offs between different functional types. A simple disturbance-based functional group system is discussed.
Keywords: disturbance; Fire ecology; gap models; Mediterranean; resprouting

Mediterranean vegetation dynamics: modelling problems and functional types - Pausas, J. G. (Plant Ecology, 1999)
Gap models have been applied to a wide range of ecosystems, mainly temperate and boreal forests, but rarely have such models been applied to Mediterranean ecosystems. In the present review we address some problems of gap models for predicting the long-term dynamics of Mediterranean ecosystems, and we suggest plant functional types suitable for modelling based on responses to disturbance. Most gap models do not take into account different life forms, interactions with ﬁre (e.g., resprouting and stimulation of the germination), and underground structures. Long term human impact on Mediterranean ecosystems has made a signiﬁcant impact on the current landscapes. That intense land use, involving long-lived slow-growing species, has had long-term consequences. It is not possible to understand Mediterranean vegetation and to validate any model without considering these factors. The lack of data for Mediterranean species may be overcome by taking into account correlations of traits and trade-offs between different functional types. A simple disturbance-based functional group system is discussed.
Keywords: disturbance; Fire ecology; gap models; Mediterranean; resprouting

metal contents in Parmelia caperata(L.) Ach. compared to bulk deposition, throughfall and leaf-wash fluxes in two holm oak forests in Montseny (NE Spain) - Rodrigo, a; Avila, a; Gómez-Bolea, A (Atmospheric Environment, 1999)
The metal concentrations of V, Cr, Co, Ni, Cu, Zn, Cd, Hg and Pb were analysed in distilled water extracts of Parmelia caperata and in bulk deposition, throughfall and an experimental in situ washing of leaves at two forests at Montseny (NE Spain) submitted to di¤erential exposure to the industrial and tra¦c activities around Barcelona. Lichen concentra- tions of Zn, Cu, V, and Cd were higher at the site of greater exposure to pollutants. Consistently, there was higher dry deposition of these metals at the more exposed site. The order of abundance of trace metals in the lichen was similar to that in the deposition variables, although Pb and Cu had intermediate concentrations in the lichen but were very low in the deposition measurements. This indicated the higher a¦nity of Pb and Cu for the exchange sites in the lichen cell wall and the fact that lichens accumulated Pb for the last 12Ð18 y when emissions were much higher than today. The ability of Parmelia caperata to indicate the deposition of heavy metals, together with its easy sampling and handling, its broad distribution and its easy identiÞcation suggest that the lichen extract procedure described here could be used to establish gradients of atmospheric deposition of heavy metals at a general geographic level
Keywords: atmospheric deposition; bulk deposition; parmelia caperata; Quercus ilex; throughfall; trace metal

metal contents in Parmelia caperata(L.) Ach. compared to bulk deposition, throughfall and leaf-wash fluxes in two holm oak forests in Montseny (NE Spain) - Rodrigo, A.; Avila, A.; Gómez-Bolea, A. (Atmospheric Environment, 1999)
The metal concentrations of V, Cr, Co, Ni, Cu, Zn, Cd, Hg and Pb were analysed in distilled water extracts of Parmelia caperata and in bulk deposition, throughfall and an experimental in situ washing of leaves at two forests at Montseny (NE Spain) submitted to di¤erential exposure to the industrial and tra¦c activities around Barcelona. Lichen concentra- tions of Zn, Cu, V, and Cd were higher at the site of greater exposure to pollutants. Consistently, there was higher dry deposition of these metals at the more exposed site. The order of abundance of trace metals in the lichen was similar to that in the deposition variables, although Pb and Cu had intermediate concentrations in the lichen but were very low in the deposition measurements. This indicated the higher a¦nity of Pb and Cu for the exchange sites in the lichen cell wall and the fact that lichens accumulated Pb for the last 12Ð18 y when emissions were much higher than today. The ability of Parmelia caperata to indicate the deposition of heavy metals, together with its easy sampling and handling, its broad distribution and its easy identiÞcation suggest that the lichen extract procedure described here could be used to establish gradients of atmospheric deposition of heavy metals at a general geographic level
Keywords: atmospheric deposition; bulk deposition; parmelia caperata; Quercus ilex; throughfall; trace metal

A model of stand dynamics for holm oak-aleppo pine forests - Zavala, M A (Ecology of Mediterranean Evergreen Oak Forests, 1999)
Understanding the mechanisms controlling forest species dynamics and composition is a fundamental issue in silviculture and plant ecology (Oliver and Larson 1990; Crawley 1997). Over the last few decades a growing literature on ecophysiology, population biology and ecosystem ecology has contributed to the empirical, expertise developed by practical forestry during the last century. As a whole these disciplines have documented some of the most important processes that take place in forest ecosystems at different levels of biological organization, from leaf physiology to ecosystem function. Nevertheless, there is a rather limited understanding of how species differences scale from physiology to whole plant performance and how these whole plant processes interact with competition to determine stand dynamics and composition.
APS
Keywords: ecophysiology; ecosystem ecology; forest species; Modelacao - crescimento; population biology

Modelling leaf gas exchange in holm-oak trees in southern Spain - Infante, J M; Damesin, C (Agricultural and Forest …, 1999)
This paper presents a mechanistically based C3 leaf CO2 assimilation model linked with an empirical stomatal model to simulate Quercus ilex leaf net photosynthesis and transpiration in oak-savannah ecosystems of southern Spain. The model estimates (time integration) daily and seasonal changes in carbon ®xation, transpiration, and water use ef®ciency of a single leaf in free air. Simulations were carried out on two trees for a dry year. Results shown in our study demonstrate that the modelling approach, compared to ®eld measurements, provides a realistic description of diurnal and seasonal patterns of leaf gas-exchange response to different environmental conditions, and as affected by water availability
Keywords: carbon dioxide assimilation; Drought; leaf gas exchange; oak savannah; photosynthesis model; Quercus ilex

Modelling leaf gas exchange in holm-oak trees in southern Spain - Infante, J. M.; Damesin, C. (Agricultural and Forest …, 1999)
This paper presents a mechanistically based C3 leaf CO2 assimilation model linked with an empirical stomatal model to simulate Quercus ilex leaf net photosynthesis and transpiration in oak-savannah ecosystems of southern Spain. The model estimates (time integration) daily and seasonal changes in carbon ®xation, transpiration, and water use ef®ciency of a single leaf in free air. Simulations were carried out on two trees for a dry year. Results shown in our study demonstrate that the modelling approach, compared to ®eld measurements, provides a realistic description of diurnal and seasonal patterns of leaf gas-exchange response to different environmental conditions, and as affected by water availability
Keywords: carbon dioxide assimilation; Drought; leaf gas exchange; oak savannah; photosynthesis model; Quercus ilex

Molecular-cytogenetic studies of ribosomal genes and heterochromatin reveal conserved genome organization among 11 Quercus species - Zoldos, V; Papes, D; Cerbah, M; Panaud, O; Besendorfer, V; Siljak-Yakovlev, S (TAG Theoretical and Applied Genetics, 1999)
Genomes of 11 Quercus species were characterized using cytogenetic (Giemsa C-banding, fluorochrome banding), molecular-cytogenetic (fluorescence in situ hybridization, FISH, to ribosomal genes) and molecular (dot-blot for ribosomal gene-copy number assessment) techniques. Ribosomal genes are the first DNA sequences to be physically mapped in oaks, and the copy number of the 18S-5.8S-26 S rRNA genes is estimated for the first time. Oak karyotypes were analysed on the basis of DAPI banding and FISH patterns; five marker chromosomes were found. In addition, chromosomal organization of ribosomal genes with respect to AT- and GC-differentiated heterochromatin was studied. Fluorochrome staining produced very similar CMA/DAPI banding patterns, and the position and number of ribosomal loci were identical for all the species studied. The 18S-5.8S-26 S rRNA genes in oak complements were represented by a major locus at the subterminal secondary constriction (SC) of the only subtelocentric chromosome pair and a minor locus at paracentromeric SC of one metacentric pair. The only 5 S rDNA locus was revealed at the paracentromeric region of the second largest metacentric pair. A striking karyotypic similarity, shown by both fluorochrome banding and FISH patterns, implies close genome relationships among oak species no matter their geographic origin (European or American) or their ecophysiology (deciduous or evergreens). Dot-blot analysis gave preliminary evidence for different copy numbers of 18S-5.8S-26 S rRNA genes in diploid genomes of Q. cerris, Q. ilex, Q. petraea, Q. pubescens and Q. robur (2700, 1300, 2200, 4000 and 2200 copies, respectively) that was correlated with the size polymorphism of the major locus.
Keywords: 18S-5.8S-26 S and 5 S rRNA genes; FISH; Fluorochrome banding; Heterochromatin; karyotype; Quercus

Near infrared spectroscopy prediction of mineral content in botanical fractions from semi-arid grasslands - Ruano-Ramos, A; García-Criado, B (Animal feed science and technology, 1999)
Near infrared reflectance spectroscopy (NIRS) was assessed for its capacity to estimate the mineral content of semi-arid grassland samples. NIRS calibrations were derived for P, K, Ca and Mg contents. Four populations of samples were used: total herbage, with a heterogeneous and complex botanical composition, and its botanical components (grasses, legumes and forbs). One set of samples from each population was selected to develop the specific calibration equations using three mathematical data treatments (log 1/R, first derivative, and second derivative). Reference values from the calibration sample set were regressed on the corresponding spectral data using stepwise multiple regression analysis. The equations were validated with samples from the same four populations that had not been included in the calibration. The NIRS method afforded acceptable accuracy in the prediction of P, K, Ca and Mg contents in the total herbage population and its botanical fractions. Botanical composition and mathematical treatment affected both the accuracy and precision of NIRS analyses; in this sense, the best fits were usually obtained using samples of simpler botanical composition (legumes and grasses), while the first derivative usually led to better results in the estimation of most parameters. # 1999 Elsevier Science B.V. All rights reserved.
Keywords: forbs; Grasses; grassland samples; legumes; Mineral content; near infrared spectroscopy

Paracrobeles psammophilus sp. nov.(Nematoda: Cephalobidae) from El Saler, Valencia (Spain) - Navarro, P; Lluch, J (Journal of Zoology, 1999)
Paracrobeles psammophilus sp. nov. (Nematoda: Cephalobidae) is described from soil of the Dehesa de El Saler (province of Valencia, Spain). This is the second record of a species of the genus Paracrobeles Heyns, 1968. The new species is characterized by rounded cheilorhabdions and the large spicules and gubernaculum of males.
Keywords: morphological features (voyant); new species; Paracrobeles

PARÁMETROS PRODUCTIVOS Y REPRODUCTIVOS EN UN REBAÑO DE OVINO TALAVERANO DURANTE LA TRANSFORMACIÓN EN PASTOS DE UN CULTIVO - López-Carrasco, C; Rodriguez, R; Robledo, J C (Pastos, 1999)
The aim of the present paper is to evalúate the effects of phosphate fertilization on animal performance in a trial of pasture regeneration on an abandoned oat culture in a dehesa system at NW of Toledo province (Spain), during four consecutive years. Fertility, prolificacy and other productive features (meat production, flock live weight evolution , stocking rate, etc.) were compared between an abandoned culture with or without fertilisation and a semi-natural pasture. Reproductive Índices were similar between treatments across experimental period. Live weight variations and body condition were affected by years through the different pasture production; the results of fertilized pastures were better than natural pasture, especially in wet springs. Although the stocking rate was higher in fertilised pasture than in natural pasture, meat production (kg lamb/ha) was similar for both treatments. If higher stocking rates had been established meat production (kg/ha) could have been increased according to the results of pasture production, live weight and body condition. The low number of weaned lambs per ewe at tupping and the difficulties to adjust the stocking rates, limited the positive effects of fertilization. Key
Keywords: dehesa system; fertilized pasture; meat production; Pastures regeneration

PARÁMETROS PRODUCTIVOS Y REPRODUCTIVOS EN UN REBAÑO DE OVINO TALAVERANO DURANTE LA TRANSFORMACIÓN EN PASTOS DE UN CULTIVO - López-Carrasco, C.; Rodriguez, R.; Robledo, J. C. (Pastos, 1999)
The aim of the present paper is to evalúate the effects of phosphate fertilization on animal performance in a trial of pasture regeneration on an abandoned oat culture in a dehesa system at NW of Toledo province (Spain), during four consecutive years. Fertility, prolificacy and other productive features (meat production, flock live weight evolution , stocking rate, etc.) were compared between an abandoned culture with or without fertilisation and a semi-natural pasture. Reproductive Índices were similar between treatments across experimental period. Live weight variations and body condition were affected by years through the different pasture production; the results of fertilized pastures were better than natural pasture, especially in wet springs. Although the stocking rate was higher in fertilised pasture than in natural pasture, meat production (kg lamb/ha) was similar for both treatments. If higher stocking rates had been established meat production (kg/ha) could have been increased according to the results of pasture production, live weight and body condition. The low number of weaned lambs per ewe at tupping and the difficulties to adjust the stocking rates, limited the positive effects of fertilization. Key
Keywords: dehesa system; fertilized pasture; meat production; Pastures regeneration

Penetration of UV-A, UV-B and blue light through the leaf trichome layers of two xeromorphic plants, olive and oak, measured by optical fibre microprobes - Karabourniotis, George; Bornman, Janet F. (Physiologia Plantarum, 1999)
Quartz fibre-optic microprobes were used to monitor the light microenvironment beneath trichome layers of the xeromorphic leaves of two Mediterranean evergreen sclerophylls, Olea europaea and Quercus ilex. Young developing leaves of both plants were densely pubescent on both surfaces of the lamina, whereas the mature leaves were pubescent only on the abaxial side. Trichome layers of young as well as of mature leaves of both plants attenuated almost all incident ultraviolet (UV)-B (310 nm) and UV-A (360 nm) radiation and a considerable portion of blue light (430 nm). Abaxial trichome layers of young leaves were more effective in screening out the incident radiation compared to the adaxial ones of the same leaves and also compared to the abaxial layer of the mature leaves. The abaxial epidermis of dehaired mature leaves of O. europaea was ineffective in absorbing most of the incident UV-B and UV-A radiation. UV and visible spectra beneath trichome layers of O. europaea in mature leaves confirmed that the light microenvironment on the epidermis was deprived in the UV-B, UV-A and partly in the blue spectral regions. It is proposed that the occurrence of a dense trichome layer, especially in young leaves, may play a protective role against not only UV-B radiation damage, but also against high visible irradiance. This function is performed irrespective of the differing anatomy of individual hairs of both plants. The protection provided by the trichomes could afford advantages under stress conditions, especially during leaf development.
The following values have no corresponding Zotero field: publisher: Munksgaard International Publishers
Keywords: Abaxial; Adaxial (voyant); leaves; light; trichome layers

Penetration of UV-A, UV-B and blue light through the leaf trichome layers of two xeromorphic plants, olive and oak, measured by optical fibre microprobes - Karabourniotis, George; Bornman, Janet F (Physiologia Plantarum, 1999)
Quartz fibre-optic microprobes were used to monitor the light microenvironment beneath trichome layers of the xeromorphic leaves of two Mediterranean evergreen sclerophylls, Olea europaea and Quercus ilex. Young developing leaves of both plants were densely pubescent on both surfaces of the lamina, whereas the mature leaves were pubescent only on the abaxial side. Trichome layers of young as well as of mature leaves of both plants attenuated almost all incident ultraviolet (UV)-B (310 nm) and UV-A (360 nm) radiation and a considerable portion of blue light (430 nm). Abaxial trichome layers of young leaves were more effective in screening out the incident radiation compared to the adaxial ones of the same leaves and also compared to the abaxial layer of the mature leaves. The abaxial epidermis of dehaired mature leaves of O. europaea was ineffective in absorbing most of the incident UV-B and UV-A radiation. UV and visible spectra beneath trichome layers of O. europaea in mature leaves confirmed that the light microenvironment on the epidermis was deprived in the UV-B, UV-A and partly in the blue spectral regions. It is proposed that the occurrence of a dense trichome layer, especially in young leaves, may play a protective role against not only UV-B radiation damage, but also against high visible irradiance. This function is performed irrespective of the differing anatomy of individual hairs of both plants. The protection provided by the trichomes could afford advantages under stress conditions, especially during leaf development.
Keywords: Abaxial; Adaxial (voyant); leaves; light; trichome layers

Pinus halepensis and Quercus ilex terpene emission as affected by temperature and humidity - Llusia, J; Penuelas, J (Biologia Plantarum, 1999)
The short-term relationships of monoterpene emission with temperature and relative humidity were studied in Pinus halepensis L. and Quercus ilex L. seedlings grown in air-conditioned chamber. In P. halepensis terpene emission rate increased with temperature (from 15 to 35 °C) and relative humidity (from 40 - 60 to 65 - 95 %). In Q. ilex, a terpene non-storing species, it increased with temperature only at high relative humidities but not at relative humidities lower than 60 %.
Keywords: a-pinene; limonene; myrcene; terpene non-storing species; terpene storing species

Plant functional types and ecosystem function in Mediterranean shrubland - Barradas, Díaz; Zunzunegui, M. (Journal of Vegetation Science, 1999)
This study attempts to identify Plant Functional Types (PFTs) within the scrub vegetation of the stabilized sand dunes of the Doñana National Park (southwestern Spain) and to explore possible links with ecosystem function. Two 10-km long transects were sampled along a gradient of water table depth from elevated and dry dunes to a border area close to the salt marsh. A matrix of cover values for 20 woody species × 58 plots and a matrix of 24 morphological and physiological traits × 20 species were analysed by means of DCA and TWINSPAN to identify the main vegetation types and PFTs. In order to know the predominant plant traits, the matrix of 20 species × 58 plots was multiplied by the 24 traits × 20 species matrix. The resulting 24 traits × 58 plots matrix was analysed by means of DCA. The main vegetation types coincide with the previous descriptions of the Park with Juniperus phoenicea woodland and xerophytic species dominating the top of the dunes and hygrophytic species with isolated Quercus suber trees in the depressions. Previous classifications of Mediterranean woody plants resulted in two main PFTs. The present analysis confirmed these two groups: maquis versus garrigue, but added four new groups. The analysis of the traits × plots matrix revealed that the main trend of variation is related to the water table gradient, while the traits related to the species of mature plant communities had little weight in the analysis because these communities are restricted to isolated patches.
Keywords: Doñana; Plant trait; Regeneration; water potential; Water table depth

Plant functional types and ecosystem function in Mediterranean shrubland - Barradas, Díaz; Zunzunegui, M (Journal of Vegetation Science, 1999)
This study attempts to identify Plant Functional Types (PFTs) within the scrub vegetation of the stabilized sand dunes of the Doñana National Park (southwestern Spain) and to explore possible links with ecosystem function. Two 10-km long transects were sampled along a gradient of water table depth from elevated and dry dunes to a border area close to the salt marsh. A matrix of cover values for 20 woody species × 58 plots and a matrix of 24 morphological and physiological traits × 20 species were analysed by means of DCA and TWINSPAN to identify the main vegetation types and PFTs. In order to know the predominant plant traits, the matrix of 20 species × 58 plots was multiplied by the 24 traits × 20 species matrix. The resulting 24 traits × 58 plots matrix was analysed by means of DCA. The main vegetation types coincide with the previous descriptions of the Park with Juniperus phoenicea woodland and xerophytic species dominating the top of the dunes and hygrophytic species with isolated Quercus suber trees in the depressions. Previous classifications of Mediterranean woody plants resulted in two main PFTs. The present analysis confirmed these two groups: maquis versus garrigue, but added four new groups. The analysis of the traits × plots matrix revealed that the main trend of variation is related to the water table gradient, while the traits related to the species of mature plant communities had little weight in the analysis because these communities are restricted to isolated patches.
Keywords: Doñana; Plant trait; Regeneration; water potential; Water table depth

Post forest-fire hydrochemical behaviour of the Rimbaud catchment (Massif des Maures, France) - Martin, C; Chevalier, Y (ZEITSCHRIFT FUR GEOMORPHOLOGIE, 1999)
In August 1990, a forest fire devastated 84 % of the Rimbaud catchment area (1.46 km(2)). This catchment presents a substratum composed of gneiss. Its relief is sharp. Soils are skeletal. The forest fire destroyed a maquis (with treelike heather and arbustus) interspersed with cork oaks and maritime pines. The fire's effects on the chemical composition of the runoff have remained light in terms of low flows. On the other hand, mineralization has greatly increased during flood, especially at the beginning of the 1990-91 water year. The paper reports on the observations conducted during four years after the fire. Dissolved outputs and hydrochemical balances are compared with results obtained on the same catchment before the forest fire, and on the Boussicaut catchment (0.74 km(2)), which is very close by, but which was not burnt.
APS
Keywords: chemical composition; Cork oak; forest fire; Maquis; maritime pine; runoff

Preferencias y actitudes de los consumidores extremeños de quesos - Mesías Díaz, Francisco Javier; Rodríguez de Ledesma Vega, Antonio; Escribano Sánchez, Miguel; Coleto Martímez, J M; Pulido García, Francisco (Simposio Internacional. Caracterización de los productos ganaderos de la dehesa, 1999)
A pesar de la fuerte evolución al alza registrada en los últimos años, España sigue siendo uno de los países de menor consumo de quesos dentro de la UE. De este incremento del consumo se han beneficiado los quesos de mayor calidad -curados y semicurados-, de los que Extremadura tiene una variada oferta y que suponen un importante sostén de la ganadería que se desarrolla en el ecosistema dehesa. En esta comunicación se analizan datos sobre el tipo de queso consumido, razones por las que se consume el queso, evolución en el consumo y tratamiento por los consumidores de las denominaciones de origen, procedentes todos ellos de una encuesta realizada a consumidores dentro del Proyecto de Investigación del Programa Sectorial I+D del MAPA “La comercialización de los quesos en Extremadura”, como forma de conocer las tendencias y potencialidades de este sector en dicha Comunidad Autónoma.
Keywords: consumo de queso; denominaciones de origen

Relation between climate and vegetation along a Mediterranean-Temperate boundary in central Italy - Blasi, C.; Carranza, M. L.; Filesi, L.; Tilia, A.; Acosta, A. (Global Ecology and Biogeography, 1999)
The relationship between climate and vegetation was investigated along a Mediterranean-Temperate boundary in central Italy. The study area is a transition zone between the Temperate (Eurosiberian) and Mediterranean regions and has an altitudinal range of almost 1750 m. Ordination and cluster analysis were used. The results did not show any sharp boundary but a climate-vegetation mosaic ranging from upper mountain thermotype and lower hyperhumid ombrotype with Fagus sylvatica L. woodlands at higher altitudes, to meso-Mediterranean thermotype and lower subhumid ombrotype with Mediterranean maquis and Quercus ilex L. woods on the coast. Six phytoclimatic groups are distinguished and described in terms of climatic parameters, vegetation types and morphological and chorological traits. These parameters indicate a change without sharp discontinuities between groups. The Mediterranean to Temperate transition in this Tyrrhenian sector is broad and includes most of the study area.
The following values have no corresponding Zotero field: publisher: Blackwell Science Ltd
Keywords: bioclimatology; climatic indices; Mediterranean vegetation; phytoclimatic groups; temperate woodlands; transition areas

Relation between climate and vegetation along a Mediterranean-Temperate boundary in central Italy - Blasi, C; Carranza, M L; Filesi, L; Tilia, A; Acosta, A (Global Ecology and Biogeography, 1999)
The relationship between climate and vegetation was investigated along a Mediterranean-Temperate boundary in central Italy. The study area is a transition zone between the Temperate (Eurosiberian) and Mediterranean regions and has an altitudinal range of almost 1750 m. Ordination and cluster analysis were used. The results did not show any sharp boundary but a climate-vegetation mosaic ranging from upper mountain thermotype and lower hyperhumid ombrotype with Fagus sylvatica L. woodlands at higher altitudes, to meso-Mediterranean thermotype and lower subhumid ombrotype with Mediterranean maquis and Quercus ilex L. woods on the coast. Six phytoclimatic groups are distinguished and described in terms of climatic parameters, vegetation types and morphological and chorological traits. These parameters indicate a change without sharp discontinuities between groups. The Mediterranean to Temperate transition in this Tyrrhenian sector is broad and includes most of the study area.
Keywords: bioclimatology; climatic indices; Mediterranean vegetation; phytoclimatic groups; temperate woodlands; transition areas

Relations entre la qualité du liège, sa composition minérale et la composition minérale des feuilles du chêne-liège (Quercus suber L.) - Courtois, Michèle; Masson, Philippe (Ann. For. Sci., 1999)
Relationships between the quality of cork, its inorganic content and the inorganic content of the leaves of the cork-oak (Quercus suber L.). The aim of this work is to set up a relationship between the quality of cork, its inorganic content and the inorganic content of the leaves of the cork-oak. The mineral contents of both leaves and cork were identified for a range of elements (nitrogen, phosphorus, potassium, calcium, magnesium, iron, copper, zinc and manganese). The quality of the cork was evaluated by experts in the cork industry on the basis of visual assessment of cork stoppers resulting from each tree. A study of correlations between the cork inorganic contents and the quality of cork demonstrates that, among those measures, only the potassium content of cork is related to the cork quality. The cork quality seems to be independent of the leaf inorganic content, which is held to be an indicator of the cork-oak mineral nutrition. (© Inra/Elsevier, Paris.)
Keywords: Cork; inorganic content; leaf; Quality; Quercus Suber L

Relations entre la qualité du liège, sa composition minérale et la composition minérale des feuilles du chêne-liège (Quercus suber L.) - Courtois, Michèle; Masson, Philippe (Ann. For. Sci., 1999)
Relationships between the quality of cork, its inorganic content and the inorganic content of the leaves of the cork-oak (Quercus suber L.). The aim of this work is to set up a relationship between the quality of cork, its inorganic content and the inorganic content of the leaves of the cork-oak. The mineral contents of both leaves and cork were identified for a range of elements (nitrogen, phosphorus, potassium, calcium, magnesium, iron, copper, zinc and manganese). The quality of the cork was evaluated by experts in the cork industry on the basis of visual assessment of cork stoppers resulting from each tree. A study of correlations between the cork inorganic contents and the quality of cork demonstrates that, among those measures, only the potassium content of cork is related to the cork quality. The cork quality seems to be independent of the leaf inorganic content, which is held to be an indicator of the cork-oak mineral nutrition. (© Inra/Elsevier, Paris.)
Keywords: Cork; inorganic content; leaf; Quality; Quercus Suber L

The relative sensitivity of different mediterranean plant species to ozone exposure - Inclán, R; Ribas, A; Penuelas, J; Gimeno, B S (Water, Air, & Soil Pollution, 1999)
An experimental study was performed in open-top chambers to assess the relative O3-sensitivity of the following Mediterranean woody plants: Quercus ilex ssp. ilex, Quercus ilex ssp. ballota, Olea europaea ssp. sylvestris, Ceratonia siliqua and Arbutus unedo. Assessment of O3 ‘sensitivity’ was based on the development of O3-induced visible injury and the extent of the reduction in relative growth rate induced by O3. Two-year-old seedlings were exposed in open-top chambers to charcoal filtered air (CFA), Non-filtered air (NFA) or Non-filtered air supplied with 40 ppb O3 from 09:00 to 18:00 hours (NFA+40). No clear relationships were found between the development of visible injury and effects on plant growth or accumulated biomass. Olea europea ssp. sylvestris and Quercus ilex ssp. ballota appeared to be the most O3-sensitive tree species screened; a ten month exposure to ambient O3 levels (AOT40 = 12.4 ppm.h) caused reductions in height and/or stem growth. Further research is needed to characterise the physiological, biochemical and anatomical characteristics that may underlie the ‘sensitivity’ of certain Mediterranean species to O3
Keywords: Critical levels; Mediterranean; Ozone; woody species

Responses to elevated atmospheric CO2 concentration and nitrogen supply of Quercus ilex L. seedlings from a coppice stand growing at a natural CO2 spring - Tognetti, Roberto; Johnson D., Jon (Ann. For. Sci., 1999)
Quercus ilex acorns were collected from a population of trees with a lifetime exposure to elevated atmospheric CO2 concentration (CO2), and after germination seedlings were exposed at two [CO2] (370 or 520 μmol mol-1) in combination with two soil N treatments (20 and 90 μmol mol -1 total N) in open-top chambers for 6 months. Increasing [CO2 ] stimulated photosynthesis and leaf dark respiration regardless of N treatment. The increase in photosynthesis and leaf dark respiration was associated with a moderate reduction in stomatal conductance, resulting in enhanced instantaneous transpiration efficiency in leaves of seedlings in CO2 enriched air. Elevated [CO2] increased biomass production only in the high-N treatment. Fine root/foliage mass ratio decreased with high-N treatment and increased with CO2 enrichment. There was evidence of a preferential shift of biomass to below-ground tissue at a low level of nutrient addition. Specific leaf area (SLA) and leaf area ratio (LAR) decreased significantly in leaves of seedlings grown in elevated [CO2] irrespective of N treatment. Leaf N concentration decreased significantly in elevated [CO2] irrespective of N treatment. As a result of patterns of N and carbon concentrations, C/N ratio generally increased with elevated [CO2] treatment and decreased with high nutrient supply. Afternoon starch concentrations in leaves did not increase significantly with increasing [CO2], as was the case for morning starch concentrations at low-N supply. Starch concentrations in leaves, stem and roots increased with elevated [CO2] and decreased with nutrient addition. The concentration of sugars was not significantly affected by either CO 2 or N treatments. Total foliar phenolic concentrations decreased in seedlings grown in elevated [CO 2] irrespective of N treatment, while nutrient supply had less of an effect. We conclude that available soil N will be a major controlling resource for the establishment and growth of Q. ilex in rising [CO 2] conditions
Keywords: carbon physiology; elevated [CO2]; natural CO2 springs; nitrogen; Quercus ilex

Respostas fotoquímicas e fenológicas de uma espécie perenifólia e de uma espécie semi-decídua durante o Inverno mediterrânico. - Oliveira, Graca; Penuelas, Josep (Revista de Biologia, 1999)

Rhetoric and reality of reforestation methods for soil and water conservation in Guadalajara (Spain) - Garcia Perez, J D (Land Degradation & Development, 1999)
Foresters have played an important part in the Spanish national strategy against land degradation. It might be expected that after the changes restored political democracy in Spain in the late 1970s, a reorganization of the way the planning and implementation of soil and water conservation projects through reforestation would be changed. This paper considers the case of Guadalajara province as an example of the way in which reforestation has been eected at national level, and the consequences for the ecosystem. It examines how, since the 1940s, the technical methods used by forestry technicians have changed from concerns with protection to those of wood production. Although reforestation methods for wood production have been recognized as detrimental to soil and water conservation, they continue to be used even in the face of considerable opposition by local people and environmental pressure groups. The paper concludes that claims for soil protection mask a policy of wood production, excluding aected people from the decision-making process.
Keywords: Land degradation; planning; reality; reforestation methods; rhetoric

Role of Photoprotective Systems of Holm-Oak (Quercus ilex) in the Adaptation to Winter Conditions - García-Plazaola, Josá I.; Artetxe, Unai; Duñabeitia, Miren K.; Becerril, Josá M. (Journal of Plant Physiology, 1999)
Holm-oak (Quercus ilex L.) is a Mediterranean evergreen sclerophyllous species adapted to a wide range of environmental conditions and consequently its leaves must be able to withstand variable stresses. Changes in pigment and antioxidant composition were assessed in relation to chilling stress, light environment and leaf aging. Photosynthetic capacity during winter was rwo-fold higher than in spring. However, the photochemical efficiency of PSI! was reduced in sun leaves probably because of an increased rate of thermal energy dissipation related to the superior zeaxanthin concentration. Lutein, neoxanthin, ~-carotene and the xanthophyll cycle pool increased during winter especially in sun leaves, while lutein epoxide and a-carotene decreased markedly. The main antioxidant accumulated during winter was ascorbate, while glutathione and a-tocopherol were not seasonally affected. Catalase increased in spring as a consequence of higher photorespiration rates, while GR and MOHAR activities were higher in sun leaves during winter. The high MOHAR activity indicates an important role for this enzyme in the adaptation to environmental factors associated to winter. The present study demonstrates that holm-oak is able to acclimate to a variety of environmental stress factors by inducing dramatic changes in their photosynthetic characteristics, pigment composition and antioxidant defences.
Keywords: antioxidants; chilling; Mediterranean evergreens; Quercus ilex; sun/shade; xanthophylls

Role of Photoprotective Systems of Holm-Oak (Quercus ilex) in the Adaptation to Winter Conditions - García-Plazaola, Josá I; Artetxe, Unai; Duñabeitia, Miren K; Becerril, Josá M (Journal of Plant Physiology, 1999)
Holm-oak (Quercus ilex L.) is a Mediterranean evergreen sclerophyllous species adapted to a wide range of environmental conditions and consequently its leaves must be able to withstand variable stresses. Changes in pigment and antioxidant composition were assessed in relation to chilling stress, light environment and leaf aging. Photosynthetic capacity during winter was rwo-fold higher than in spring. However, the photochemical efficiency of PSI! was reduced in sun leaves probably because of an increased rate of thermal energy dissipation related to the superior zeaxanthin concentration. Lutein, neoxanthin, ~-carotene and the xanthophyll cycle pool increased during winter especially in sun leaves, while lutein epoxide and a-carotene decreased markedly. The main antioxidant accumulated during winter was ascorbate, while glutathione and a-tocopherol were not seasonally affected. Catalase increased in spring as a consequence of higher photorespiration rates, while GR and MOHAR activities were higher in sun leaves during winter. The high MOHAR activity indicates an important role for this enzyme in the adaptation to environmental factors associated to winter. The present study demonstrates that holm-oak is able to acclimate to a variety of environmental stress factors by inducing dramatic changes in their photosynthetic characteristics, pigment composition and antioxidant defences.
Keywords: antioxidants; chilling; Mediterranean evergreens; Quercus ilex; sun/shade; xanthophylls

Root and shoot hydraulic conductance of seven Quercus species - Nardini, Andrea; Tyree T., Melvin (Ann. For. Sci., 1999)
The root (KR) and shoot (KS) hydraulic conductances of seven different Quercus species, as well as the leaf blade hydraulic resistance (RLL), were measured in potted plants with the aim of understanding whether a relationship exists between the hydraulic architecture and the general ecological behaviour of different species of this genus. The KR values were scaled by dividing by root surface area (KRR) and by leaf surface area (KRL) and the KS values were scaled by dividing by leaf surface area (KSL). The likely drought-adapted species (Quercus suber, Q. pubescens, Q. petraea) showed lower KRL and KRR, lower KSL and higher RLL with respect to the known water-demanding species (Q. alba, Q. cerris, Q. robur, Q. rubra). The possible physiological and ecological significance of such differences are discussed.
Keywords: high pressure flow meter; leaf blade resistance; Quercus; Root hydraulic conductance; shoot hydraulic conductance

Same fungi associated with Platypus cylindrus F. (Coleoptera : Platypodidae) on Quercus suber L.: toxicity bioassays - Sousa, E M R; Guedes, M E M (PHYSIOLOGY AND GENETICS OF TREE-PHYTOPHAGE INTERACTIONS - INTERNATIONAL SYMPOSIUM, 1999)
Recently, new fungi symbiosis were detected in association with high population levels of P. cylindrus in portuguese cork oak stands. The toxicity of these fungi was assessed by a bioassay method, with a dense suspension of Cladosporium cucumerinum ELL. et Art, however only Nodulisporium sp. has shown the presence of a biocidal compound.

Seasonal embolism and xylem vulnerability in deciduous and evergreen Mediterranean trees influenced by proximity to a carbon dioxide spring - Tognetti, Roberto; Longobucco, Anna; Raschi, Antonio (Tree Physiology, 1999)
We investigated how proximity to natural CO2 springs affected the seasonal patterns of xylem embolism in Quercus ilex L., Quercus pubescens Willd., Fraxinus ornus L., Populus tremula L. and Arbutus unedo L., which differ in leaf phenology and wood anatomy. Xylem embolism was evaluated in both artificially dehydrated branches and in hydrated apical branches collected at monthly intervals during a 20-month sampling period. Initial specific hydraulic conductivity was also evaluated. We found species-dependent differences in xylem hydraulic properties in response to elevated CO2 concentration. Populus tremula was the most embolized and A. unedo was the least embolized of the species examined. Effects of elevated CO2 were significant in Q. pubescens, P. tremula and A. unedo, whereas the overall response to elevated CO2 was less evident in F. ornus and Q. ilex. Specific hydraulic conductivity differed among species but not between sites, although the interaction between species and site was significant. Differences in xylem vulnerability between trees growing near to the CO2 spring and those growing in control areas were small. Although differences in hydraulic properties in response to elevated CO2 concentration were small, they may be of great importance in determining future community composition in Mediterranean-type forest ecosystems. The possible causes and ecological significance of such differences are discussed in relation to elevated CO2 concentration and other environmental conditions.
10.1093/treephys/19.4-5.271
Keywords: cavitation; CO2 springs; diffuse-porous; Global change; hydraulic conductivity; Mediterranean-type ecosystems; ring-porous; semiring-porous

Seasonal emission of monoterpenes by the Mediterranean tree Quercus ilex in field conditions: Relations with photosynthetic rates, temperature and volatility - Penuelas, Josep; Llusia, Joan (Physiologia Plantarum, 1999)
The relationships of monoterpene emission with temperature, light, photosynthesis and stomatal conductance (gs) were studied in Quercus ilex L. trees throughout the four annual seasons under field conditions. The highest monoterpene emission was measured in spring and summer (midday average of 11 μg [g DW]−1 h−1), whereas the lowest rates were found in autumn and winter (midday averages of 0.51 and 0.23 μg [g DW]−1 h−1, respectively). In spring and summer, limonene was the monoterpene emitted at highest rate (midday averages of 5.27–6.69 μg [g DW]−1 h−1), whereas α-pinene was emitted the most in autumn and winter (midday averages of 0.31 μg [g DW]−1 h−1). The monoterpenes limonene, α-pinene and β-pinene represented about 75–95% of total detected monoterpenes. The total monoterpene emission rates represented about 0.04% of carbon fixed in autumn, 0.17% in winter, 0.84–2.51% in spring and 1.22–5.13% in summer. Significant correlations of total monoterpene emission with temperature were found when considering either summer emission or the emission over the entire year, whereas significant correlations with net photosynthetic rates were only found when considering summer season. Among individual terpenes, the most volatile, α-pinene and β-pinene, were more correlated with temperature than with net photosynthetic rates whereas the less volatile limonene was more correlated with net photosynthetic rate. Thus, under field conditions it seems that dependency of monoterpene emission on photosynthetic rate or temperature is partly related with volatility of the compounds. Influences of seasonality, temperature, photosynthetic rates and volatility should be considered in inventories and models of emission rates in Mediterranean ecosystems.
Keywords: monoterpene emission rates; photosynthetic rates; seasonal variation (voyant); Temperature; volatility

Sexual reproduction in the cork oak (Quercus suber L.). I. The progamic phase - Boavida, L C; Varela, M C; Feijo, J A (Sexual Plant Reproduction, 1999)
Cork oak (Quercus suber L.) is a monoecious wind-pollinated species with a protandrous system to ensure cross-pollination. To the best of our knowledge, this report provides the first insight into the sexual reproduction cycle in this species. The cork oak flowering season extends from April until the end of May. Our results show that, at anthesis, the pistillate flower is not completely formed and ovules are just starting to develop. Pollen reaching the dry stigmatic surface adheres to the receptive cells, germinates and penetrates the epidermis in aproximately 24 h, and grows through the intercellular spaces of a solid transmitting tissue. In cross-pollination, a sequential arrest of pollen tubes was observed along the style, providing preliminary evidence for a pollen tube competition mechanism. As a consequence, few pollen tubes reach the basal portion of the style. Furthermore, pollen tube growth is a discontinuous process since tubes are arrested in the basal portion of the style about 10–12 days after pollination. While tubes are latent, the ovarian loculus starts to develop from an emerging mass of sporogeneous cells which later will differentiate into the placenta and ovules. One and a half months after pollination ovules complete their differentiation, tubes resume growth and fertilisation occurs. Ovular abortion is frequent at this stage, and only one ovule will successfully mature during autumn into a monospermic seed.
Keywords: Cork oak; Ovule abortion; Pollen tube arrest; Pollen tube competition; Quercus suber

Sexual reproduction in the cork oak (Quercus suber L.). I. The progamic phase - Boavida, L. C.; VARELA, M. C.; Feijo, J. A. (Sexual Plant Reproduction, 1999)
Cork oak (Quercus suber L.) is a monoecious wind-pollinated species with a protandrous system to ensure cross-pollination. To the best of our knowledge, this report provides the first insight into the sexual reproduction cycle in this species. The cork oak flowering season extends from April until the end of May. Our results show that, at anthesis, the pistillate flower is not completely formed and ovules are just starting to develop. Pollen reaching the dry stigmatic surface adheres to the receptive cells, germinates and penetrates the epidermis in aproximately 24 h, and grows through the intercellular spaces of a solid transmitting tissue. In cross-pollination, a sequential arrest of pollen tubes was observed along the style, providing preliminary evidence for a pollen tube competition mechanism. As a consequence, few pollen tubes reach the basal portion of the style. Furthermore, pollen tube growth is a discontinuous process since tubes are arrested in the basal portion of the style about 10–12 days after pollination. While tubes are latent, the ovarian loculus starts to develop from an emerging mass of sporogeneous cells which later will differentiate into the placenta and ovules. One and a half months after pollination ovules complete their differentiation, tubes resume growth and fertilisation occurs. Ovular abortion is frequent at this stage, and only one ovule will successfully mature during autumn into a monospermic seed.
Keywords: Cork oak; Ovule abortion; Pollen tube arrest; Pollen tube competition; Quercus suber

Short-term changes of response indicators of ecosystem status in broadleaved forests in Tuscany (central Italy) - Ferretti, M; Bonini, I; Bussotti, F; Celesti, C; Cenni, E; Chiarucci, A; Cozzi, A; De Dominicis, V; Grossoni, P; Leonzio, C (WATER AIR AND SOIL POLLUTION, 1999)
The status of different response indicators of forest condition were measured and assessed between 1995 and 1997 at 6 Permanent Monitoring Plots (PMPs) in Tuscany (central Italy), where beech, holm oak and Turkey oak are the most frequent tree species. Foliage transparency, leaf damage and crown dieback have changed significantly over the monitoring period. Leaf area, length of the current year shoots, and total leaf area changed as well, but only for Turkey oak. Changes were consistent between and within the plots. Different indices of plant diversity showed marked changes, apparently linked to natural dynamics within individual ecosystems. These rapid and contrasting fluctuations in the various indicators of forest ecosystem make it difficult to derive a synthesis about the general condition of ecosystems and - especially - about the effects of air pollution.
Keywords: Biodiversity; crown condition; crown productivity; forest health; long-term monitoring; Permanent plots; response indicators

Short-term responses of terpene emission rates to experimental changes of PFD in Pinus halepensis and Quercus ilex in summer field conditions - Penuelas, J; Llusia, J (Environmental and Experimental Botany, 1999)
The diurnal relationships of monoterpene emission with PFD and photosynthetic rates were studied in the Mediterranean trees Pinus halepensis, a terpene storing species, and Quercus ilex, a non-storing species, under summer ﬁeld conditions. At morning, midday and evening, leaves were submitted to different irradiance levels by differentially shading them. Both species emitted large amounts of monoterpenes (about 20 mg g DM1 h1 ). The most emitted terpene by P. halepensis was D 3 -carene followed by b-myrcene, a-pinene and b-pinene. The most emitted terpene by Q. ilex was limonene followed by a-pinene and b-pinene. No clear correlation to temperature was found for Q. ilex emission within the diurnal range of 21–33°C, whereas P. halepensis emissions increased with the temperature. There was no consistent link between terpene emissions and PFD or photosynthetic rates for P. halepensis but there were signiﬁcant relationships for Q. ilex. However, emissions by Q. ilex became inhibited at highest PFDs and during the course of the day when net photosynthesis decreased under summer drought. The study shows that the emission rates of both species are highly variable and that during a hot Mediterranean summer day (with limited water availability) the diurnal variation of emission is not only driven by the common light and temperature dependencies. Water stress, branch-to-branch variability and other inﬂuences must explain great part of the observed variability
Keywords: a-pinene; d 3 -carene; field conditions; limonene; pfd; photosynthetic rate; Pinus halepensis; Quercus ilex; Temperature; Terpene emission

Short-term responses of terpene emission rates to experimental changes of PFD in Pinus halepensis and Quercus ilex in summer field conditions - Penuelas, J.; Llusia, J. (Environmental and Experimental Botany, 1999)
The diurnal relationships of monoterpene emission with PFD and photosynthetic rates were studied in the Mediterranean trees Pinus halepensis, a terpene storing species, and Quercus ilex, a non-storing species, under summer ﬁeld conditions. At morning, midday and evening, leaves were submitted to different irradiance levels by differentially shading them. Both species emitted large amounts of monoterpenes (about 20 mg g DM1 h1 ). The most emitted terpene by P. halepensis was D 3 -carene followed by b-myrcene, a-pinene and b-pinene. The most emitted terpene by Q. ilex was limonene followed by a-pinene and b-pinene. No clear correlation to temperature was found for Q. ilex emission within the diurnal range of 21–33°C, whereas P. halepensis emissions increased with the temperature. There was no consistent link between terpene emissions and PFD or photosynthetic rates for P. halepensis but there were signiﬁcant relationships for Q. ilex. However, emissions by Q. ilex became inhibited at highest PFDs and during the course of the day when net photosynthesis decreased under summer drought. The study shows that the emission rates of both species are highly variable and that during a hot Mediterranean summer day (with limited water availability) the diurnal variation of emission is not only driven by the common light and temperature dependencies. Water stress, branch-to-branch variability and other inﬂuences must explain great part of the observed variability
Keywords: a-pinene; d 3 -carene; field conditions; limonene; pfd; photosynthetic rate; Pinus halepensis; Quercus ilex; Temperature; Terpene emission

Structural characterization of cork lignin by thioacidolysis and permanganate oxidation - Marques, A V; Pereira, H; Meier, D; Faix, O (HOLZFORSCHUNG, 1999)
Quercus suber L. milled cork lignins obtained from extractive-free cork (MCL) and from saponified cork (MCLsap) were characterized by thioacidolysis and KMnO4 oxidation. These techniques and the previously used analytical pyrolysis revealed that cork contains a guaiacyl lignin (G lignin) with 94-96% guaiacyl-, ca. 3% syringyl-, and 2-3% of 4-hydroxyphenyl propane units. The total yields of degradation products in thioacidolysis and KMnO4 oxidation experiments were lower in comparison to those of a spruce milled wood lignin (MWLspruce) suggesting a higher cross-linking in the G-lignin of cork. The higher frequency of ``condensed{''} structures (having C-C or C-O-C linkages to aromatic rings) in cork lignin was also manifested in the relative abundance of various aromatic acids obtained by KMnO4 oxidation. The cork lignin (MCLsap) contains only low amounts (ca. 2%) of covalently bonded suberinic acids. Numerous free aliphatic suberinic acids were detected and identified in the ether soluble part of MCLsap. Ferulic acid was not liberated by thioacidolysis, pointing at an in situ acylation. We suggest that the major part of the aromatic domain in cork is a G-lignin but that it includes also another structural moiety with higher H-unit content and linked by thioacidolysis resistant bonds.
Keywords: Cork; cork lignin; ferulic acid; milled wood lignin (MWL); permanganate oxidation; Quercus suber; suberin; thioacidolysis

Studies on pharmaceutical ethnobotany in the regions of L'Alt Empordà and Les Guilleries (Catalonia, Iberian Peninsula). - Bonet, M a; Parada, M; Selga, A; Vallès, J (Journal of ethnopharmacology, 1999)
An ethnobotanical survey was carried out in two regions (L'Alt Emporda and Les Guilleries), situated in North East Catalonia (Iberian Peninsula), with an approximate area of 800 km2 and a population of 68000. Through interviews with 73 people, data was obtained on the medicinal uses of 220 species. The most important findings are presented here concerning the ethnopharmacology of those areas. One hundred and ninty four unreported or uncommon uses corresponding to 101 plant species were detected.
Keywords: Catalonia; Ethnobotany; Folk medicine; Medicinal plants; Quantitative ethnobotany

Terpenoid emissions of Mediterranean oaks and their relation to taxonomy - Csiky, O; Seufert, G (ECOLOGICAL APPLICATIONS, 1999)
This paper presents results of a laboratory screening study of biogenic emissions from Mediterranean oak species. The experiment aimed at improving our understanding of oak contributions to overall emissions of volatile organic compounds and to the atmospheric chemistry in the Mediterranean area. We measured type and amount of terpenoid emissions (isoprene, mono- and sesquiterpenes) under standard conditions of light and temperature from 14 different Quercus species of Mediterranean and American origin. Tree saplings were exposed in a controlled environment chamber, and leaf-level trace-gas exchange was analyzed with a minicuvette system and gas chromatography, to study the relation between the emission types and emission spectra found and the taxonomy of Quercus. The holarctic group Lepidobalanus and the North American groups Erythrobalanus and Protobalanus were found to be strong isoprene emitters. The Eurasian oak group Sclerophyllodrys emits monoterpenes; Cerris include mostly non-emitters, but also an isoprene and a monoterpene emitter has been found in this group. Results are discussed with respect to their implications for presently used emission scenarios.
Keywords: atmospheric chemistry; BEMA (Biogenic Emissions in the Mediterranean Area; Biogenic emission; chemo-taxonomy; isoprene; Mediterranean Region; Monoterpenes; oak taxonomy; oaks; Quercus; terpenoid emissions; trace-gas exchange; volatile organic compounds (VOCs)

Terpenoid emissions of Mediterranean oaks and their relation to taxonomy - Csiky, O.; Seufert, G. (ECOLOGICAL APPLICATIONS, 1999)
This paper presents results of a laboratory screening study of biogenic emissions from Mediterranean oak species. The experiment aimed at improving our understanding of oak contributions to overall emissions of volatile organic compounds and to the atmospheric chemistry in the Mediterranean area. We measured type and amount of terpenoid emissions (isoprene, mono- and sesquiterpenes) under standard conditions of light and temperature from 14 different Quercus species of Mediterranean and American origin. Tree saplings were exposed in a controlled environment chamber, and leaf-level trace-gas exchange was analyzed with a minicuvette system and gas chromatography, to study the relation between the emission types and emission spectra found and the taxonomy of Quercus. The holarctic group Lepidobalanus and the North American groups Erythrobalanus and Protobalanus were found to be strong isoprene emitters. The Eurasian oak group Sclerophyllodrys emits monoterpenes; Cerris include mostly non-emitters, but also an isoprene and a monoterpene emitter has been found in this group. Results are discussed with respect to their implications for presently used emission scenarios.
The following values have no corresponding Zotero field: pub-location: 1707 H ST NW, STE 400, WASHINGTON, DC 20006-3915 USA publisher: ECOLOGICAL SOC AMER
Keywords: atmospheric chemistry; BEMA (Biogenic Emissions in the Mediterranean Area; Biogenic emission; chemo-taxonomy; isoprene; Mediterranean Region; Monoterpenes; oak taxonomy; oaks; Quercus; terpenoid emissions; trace-gas exchange; volatile organic compounds (VOCs)

Treatment of oak decline using pressurized injection capsules of antifungal materials - Fernandez-Escobar, R.; Gallego, F. J.; Benlloch, M.; Membrillo, J.; Infante, J.; de Algaba, A. Perez (European Journal of Forest Pathology, 1999)
Quercus ilex and Quercus suber trees growing at several sites in Extremadura, Western Spain, that were showing symptoms of oak decline were injected with potassium phosphonate, quinosol or carbendazim using a low-pressure method of trunk injection composed of a pressurized capsule system. A team of four people injected between 120 and 189 trees per day, depending upon the density of the undergrowth vegetation. This labour cost represented, approximately, 15–20% of the total cost of the treatment. The potassium phosphonate-injected trees showed a significant improvement in vegetative growth within 2 years of the injection treatment, and they also showed some recovery from the decline symptoms during the third year. Only one injection treatment of an average of 3.5 capsules (corresponding to 24.5 g phosphonic acid) per tree of approximately 36 cm in diameter, was necessary to reduce the disease severity significantly. Indirectly, these results corroborate the implication of Phytophthora cinnamomi in oak decline within Spanish Quercus woodlands.
The following values have no corresponding Zotero field: publisher: Blackwell Publishing Ltd
Keywords: Oak decline; phosphonic acid; trunk injections (PG)

Treatment of oak decline using pressurized injection capsules of antifungal materials - Fernandez-Escobar, R; Gallego, F J; Benlloch, M; Membrillo, J; Infante, J; de Algaba, A Perez (European Journal of Forest Pathology, 1999)
Quercus ilex and Quercus suber trees growing at several sites in Extremadura, Western Spain, that were showing symptoms of oak decline were injected with potassium phosphonate, quinosol or carbendazim using a low-pressure method of trunk injection composed of a pressurized capsule system. A team of four people injected between 120 and 189 trees per day, depending upon the density of the undergrowth vegetation. This labour cost represented, approximately, 15–20% of the total cost of the treatment. The potassium phosphonate-injected trees showed a significant improvement in vegetative growth within 2 years of the injection treatment, and they also showed some recovery from the decline symptoms during the third year. Only one injection treatment of an average of 3.5 capsules (corresponding to 24.5 g phosphonic acid) per tree of approximately 36 cm in diameter, was necessary to reduce the disease severity significantly. Indirectly, these results corroborate the implication of Phytophthora cinnamomi in oak decline within Spanish Quercus woodlands.
Keywords: Oak decline; phosphonic acid; trunk injections (PG)

Trends in European cultural landscape development: perspectives for a sustainable future - Vos, W; Meekes, H (Landscape and Urban Planning, 1999)
Europe has a long history of landscape use, ranging from prehistoric to present times. Many old cultural landscapes have high qualities, but the management regime they developed under is no more feasible economically. Modern society increasingly utilizes landscape in a great variety of ways and for many purposes. This poses a complex pressure on cultural landscapes, threatening landscape qualities. Therefore planners and managers are facing the question: how can a sustainable future for old cultural landscapes, based on sound economics and the commitment of all actors be achieved? After a comprehensive overview of landscape use in the past, the various ways in which people have regarded their landscape and the ever changing attitude towards landscape use are reviewed. Modern agricultural practices, urbanization and recreation all threaten the existence of valuable cultural landscapes, but simple solutions to conserve many of these landscapes are not at hand. Perspectives for a sustainable future for historic European cultural landscapes are based on the following observations: society's demand for multifunctionality; the inclination of farmers to meet this demand if it is economically pro®table; support from national and local authorities (and the public) for ecologically sound management and ®nally, decentralization of landscape ruling and legislation, which favours regional solutions. Landscape ecology, as a study of relations on the earth's surface can tackle planning and management issues from numerous view points, each with its own focal points. Scientists from all over Europe, convening in the Netherlands, set out new directions for landscape science. Priorities for the next century include: integration between disciplines; matching of scales in time and place with users, researchers and decision makers to enhance interaction and understanding
Keywords: landscape history; Landscape planning; management bodies; research priorities; rural landscape

Urethanes and polyurethanes from suberin 2: synthesis and characterization - Cordeiro, N; Belgacem, M N; Gandini, A; Neto, C P (INDUSTRIAL CROPS AND PRODUCTS, 1999)
Polyurethanes based on suberin from cork of Quercus suber L. and conventional isocyanate monomers were prepared and fully characterized in terms of both structure (FTIR and H-1 NMR spectroscopy) and thermal properties (differential scanning calorimetry and thermogravimetric analysis). Two fractions were systematically isolated, namely (i) methylene-chloride soluble products, which corresponded to linear and branched macromolecules and (ii) methylene-chloride insoluble products, representing the crosslinked material. The structures of these polymers were regular and no appreciable side reactions were detected. DSC analyses provided information about the glass transition temperature of both fractions and this parameter was correlated with the stiffness of the isocyanate used. The TGA of these polyurethanes showed that they started to degrade at about 175 degrees C and that the residue at 400 degrees C was around 50%. The highest amounts of insoluble fractions, as well as the highest T-g,s, were reached when an initial \{[\}NCO]/\{[\}OH] of unity was used. (C) 1999 Elsevier Science B.V. All rights reserved.
Keywords: Cork; glass transition; polyurethanes; Quercus suber L.; suberin; thermal properties

Urethanes and polyurethanes from suberin 2: synthesis and characterization - Cordeiro, N.; Belgacem, M. N.; Gandini, A.; Neto, C. P. (INDUSTRIAL CROPS AND PRODUCTS, 1999)
Polyurethanes based on suberin from cork of Quercus suber L. and conventional isocyanate monomers were prepared and fully characterized in terms of both structure (FTIR and H-1 NMR spectroscopy) and thermal properties (differential scanning calorimetry and thermogravimetric analysis). Two fractions were systematically isolated, namely (i) methylene-chloride soluble products, which corresponded to linear and branched macromolecules and (ii) methylene-chloride insoluble products, representing the crosslinked material. The structures of these polymers were regular and no appreciable side reactions were detected. DSC analyses provided information about the glass transition temperature of both fractions and this parameter was correlated with the stiffness of the isocyanate used. The TGA of these polyurethanes showed that they started to degrade at about 175 degrees C and that the residue at 400 degrees C was around 50%. The highest amounts of insoluble fractions, as well as the highest T-g,s, were reached when an initial \{[\}NCO]/\{[\}OH] of unity was used. (C) 1999 Elsevier Science B.V. All rights reserved.
The following values have no corresponding Zotero field: pub-location: PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS publisher: ELSEVIER SCIENCE BV
Keywords: Cork; glass transition; polyurethanes; Quercus suber L.; suberin; thermal properties

Uso de la encina ( Quercus ilex spp . ballota ) por la hormiga Plagiolepis pygmaea ( Hymenoptera : Formicidae ) como refugio ante medios desfavorables - Ruiz, N; García, J; Reyes, G (Boln. Asoc. esp. Ent, 1999)
The P. pygmaea (LATREILLE, 1978) species utilizes the modifications created in the environment by the holm oak tree as refuge those means which are adverse, such as the Mediterranean highly sunny pastures. However, the inner part of the vegetal covering of the tree is equally adverse, that is why this species unfolds an anular pattern, a distribution which depends on the perimeter of the tree top. Even the usage of other non-biotic resources —such as, for example, the stones— as the place of nesting, is conditioned by the distance of the tree trunk factor, so that ants prefer to build their nests under a rock, more and more often as soon as they leave it.
Keywords: holm oak tree; microclimate.; Pattern; Plagiolepys pygmaea

Variability of suberin composition of reproduction cork from Quercus suber throughout industrial processing - Conde, E; GARCIA-VALLEJO, M C; Cadahía, E (HOLZFORSCHUNG, 1999)
The chemical composition of suberin was studied in cork planks from three different trees of Spanish Quercus suber at four different stages of the industrial processing of first transformation: stripping (a), first rest (b), boiling followed by open air rest (c1) and boiling followed by store-room rest (c2). The monomeric composition was determined by gas chromatography/mass spectrometry in the product of depolymerization of the free of extractives cork with sodium methoxide-methanol. The average concentrations of the main monomers were: 1-alkanols (C-20-C-26) 4.17 %; alkanoic acids (C-20-C-26) 5.99 %; alpha, omega-alkanedioic acids (C-16-C-24) 6.20 %; omega-hydroxy-alkanoic acids (C-20-C-26) 29.41 %; erythro- and threo-9, 10-dihydroxyoctadecanedioic acids 6.76 %, erythro- and threo-9,10,18-trihydroxyoctadecanoic acids 9.50 %, 9,10-epoxy-18-hydroxyoctadecanoic acid 2.72 % and 9,10-epoxy-octadecanedioic acid 2.93 % and ferulic acid 5.05 %. Significant differences were observed between samples taken at the stripping and after boiling with store room rest, and both groups of samples differed from those picked after the other two processing stages. Ten components were selected as providing the greatest discrimination among stages: 9-octadecenedioic, 18-hydroxy-9-octadecenoic, eicosanedioic and 9,10-epoxy-18-hydroxy-octadecanoic acids, tetracosanol, and five unidentified components.
Keywords: Cork; industrial processin; Quercus suber; suberin

Variability of suberin composition of reproduction cork from Quercus suber throughout industrial processing - Conde, E.; GARCIA-VALLEJO, M. C.; Cadahia, E. (HOLZFORSCHUNG, 1999)
The chemical composition of suberin was studied in cork planks fromthree different trees of Spanish Quercus suber at four different stages of the industrial processing of first transformation: stripping (a), first rest (b), boiling followed by open air rest (c1) and boiling followed by store-room rest (c2). The monomeric composition was determined by gas chromatography/mass spectrometry in the product of depolymerization of the free of extractives cork with sodium methoxide-methanol. The average concentrations of the main monomers were: 1-alkanols (C-20-C-26) 4.17 %; alkanoic acids (C-20-C-26) 5.99 %; alpha, omega-alkanedioic acids (C-16-C-24) 6.20 %; omega-hydroxy-alkanoic acids (C-20-C-26) 29.41 %; erythro- and threo-9, 10-dihydroxyoctadecanedioic acids 6.76 %, erythro- and threo-9,10,18-trihydroxyoctadecanoic acids 9.50 %, 9,10-epoxy-18-hydroxyoctadecanoic acid 2.72 % and 9,10-epoxy-octadecanedioic acid 2.93 % and ferulic acid 5.05 %. Significant differences were observed between samples taken at the stripping and after boiling with store room rest, and both groups of samples differed from those picked after the other two processing stages. Ten components were selected as providing the greatest discrimination among stages: 9-octadecenedioic, 18-hydroxy-9-octadecenoic, eicosanedioic and 9,10-epoxy-18-hydroxy-octadecanoic acids, tetracosanol, and five unidentified components.
The following values have no corresponding Zotero field: pub-location: GENTHINER STRASSE 13, D-10785 BERLIN, GERMANY publisher: WALTER DE GRUYTER & CO
Keywords: Quercus suber; suberin; cork; industrial processin

Very high-resolution 1H MAS NMR of a natural polymeric material - Gil, A M; Lopes, M H; Pascoal Neto, C; Rocha, J (Solid State Nuclear Magnetic Resonance, 1999)
The use of ultrafast magic angle spinning (>30 kHz) in tandem with delayed echo acquisition is shown to yield very high-resolution 1H MAS NMR spectra of complex natural organic materials. For the first time, very high-resolution 1H MAS NMR spectra are reported for cork and wood components, two natural materials with great economic importance. The effect of the spinning rate on the 1H NMR spectra was evaluated with single-pulse acquisition and delayed-echo acquisition. The delayed-echo acquisition spectra presented linewidths as sharp as 67 and 25 Hz. The narrow peaks, characterised by proton spin–spin and spin–lattice relaxation, were assigned to the isotropic chemical shifts and the general spectral features were shown to correlate with the sample chemical structure. The tentative assignments of cork 1H MAS NMR signals were presented.
Keywords: 1H MAS NMR; Cellulose; Cork; Lignin; Relaxation; suberin

Waxes composition of Quercus suber reproduction cork from different Spanish provenances - Conde, E.; GARCIA-VALLEJO, M. C.; Cadahia, E. (Wood Science and Technology, 1999)
The chemical composition of waxes was studied in Quercus suber cork planks collected in seven localities of the three main production areas of Spain. Waxes were extracted with chloroform (CHCl3 ) and the extract was submitted to saponi®cation in order to obtain the neutral and acid fractions. The trimethylsilyl derivatives of both fractions were analysed by GC-MS. The seven populations cannot be distinguished by their total contents of waxes (Chloroform extract) and of the neutral and acid fraction. This lack of differences could be due to the important variability among samples of each population. The neutral fraction was mainly composed of fatty alcohols (all the even members from C18 to C26 , with traces of the intermediate odd members and some unsaturated groups) and triterpenes (11 components, among them friedelin, betulin and cerin were identi®ed) and a very small amount of monocarboxylic fatty acids (C16 and C24 members) was also present. The main group of compo- nents of the acid fraction was that of fatty acids (saturated even C14±C24 and odd C15 , C17 , C21 members, accompanied by a great amount of unsaturated terms and some x-hydroxyacids, 18-hydroxy-9,12-octadecadienoic and 18-hydroxy-9-oct- adecenoic acids). Four triterpenes and the C20 and C24 alcohols were also detected in the acid fraction. Signi®cant differences were found among the corks of the various provenances in the global contents of alcohols and triterpenes and in these individual components contents of the neutral fraction. Concerning the differences among the various provenances in the contents of the groups of fatty acids, alcohols, and triterpenes in the acid fraction, a higher number of differ- ences were obtained in the comparisons of the contents of acids and triterpenes, whereas the differences were practically null in the case of the alcohols. When the differences were studied considering the individual compounds, the relation with the behaviour of the contents of the groups of components was not as clear as it happens in the neutral fraction. In this case, the differences were scarcer and they did not show a unique pattern, neither in the components, nor the populations. There is no correspondence in the differences among the provenances regarding the components of the neutral fraction or those of the acid fraction. No clear relationship was found between the geographical proximity of the provenances and chemical similarity of the waxes composition.
Keywords: Acid fraction; component (voyant); Cork; neutral fraction; provenance; waxes

Waxes composition of reproduction cork from Quercus suber and its variability throughout the industrial processing - Conde, E.; GARCIA-VALLEJO, M. C.; Cadahia, E. (Wood Science and Technology, 1999)
The chemical composition of waxes was studied in cork planks from three different trees of Spanish Quercus suber at four different stages of the in- dustrial processing of the ®rst transformation: stripping, ®rst rest, boiling fol- lowed by open air rest and boiling followed by store-room rest. Waxes were extracted with chloroform (CHCl3 ) and the extract was submitted to saponi®cation in order to obtain the neutral and acid fractions. The trimethylsilyl derivatives of both fractions were analysed by GC-MS. An important decrease of the total content of waxes -CHCl3 extract-(average values: 10.13 to 4.91%) and of the acid fraction (average values: 2.51 to 0.96%) was observed throughout the industrial processing. Some differences were also found among trees, two of them being richer in total waxes (average, 8.14 and 7.71%) than the other one (average, 4.67%). Concerning the three groups of identi®ed components (fatty acids, fatty alcohols and triterpenes), the contents of the fatty alcohols and acids suffer an important reduction during the ®rst rest (average values: 30.39 to 17.53% and 58.73 to 31.48%, respectively), while after boiling, there is a decrease of the triterpenes concentrations (79.16 to 58.00% -neutral fraction- and 40.23 to 23.20% -acid fraction-), being greater when the second rest is carried out in a store room. Signi®cant differences among trees were only found in the fatty alcohols contents. The neutral fraction was mainly composed by fatty alcohols (all the even members from C18 to C26 , with traces of intermediate odd members and some unsaturated groups, C20 and C21 ) and triterpenes (14 components, among them friedelin, betulin and cerin were identi®ed), and a very small amount of monocarboxylic fatty acids (C16 , C18 , C22 and C24 members) was also present. The main group of components of the acid fraction was that of fatty acids (saturated even C12±C24 and odd C15 , C17 , C21 members, accompanied by a great amount of unsaturated terms and some x-hydroxyacids, 18-hydroxy-9,12-octadecadienoic and 18-hydroxy-9-octadecenoic acids). Four triterpenes, the C20 , C24 and C28 alcohols and ferulic acid were also detected in the acid fraction. Some of these individual components of each fraction were also affected by the industrial processing and presented signi®cant differences among the studied trees.
Keywords: Acid fraction; component (voyant); Cork; indutrial processing stage; neutral fraction; waxes

Air pollution, forest condition and forest decline in Southern Europe: an overview. - Bussotti, F; Ferretti, M (Environmental pollution (Barking, Essex : 1987), 1998)
Over the last decades much of the work on the impact of air pollution on forests in Europe has concentrated on central and northern countries. The southern part of Europe has received far less attention, although air pollutants-especially the photochemical ones-can reach concentrations likely to have adverse effects on forest vegetation. Although international forest condition surveys present serious problems where data consistency is concerned, they reveal considerable year-by-year species-specific fluctuations rather than a large-scale forest decline. Cases of obvious decline related to environmental factors are well circumscribed: (1) the deterioration of some coastal forests due to the action of polluted seaspray; (2) the deterioration of reforestation projects, especially conifers, mainly due to the poor ecological compatibility between species and site; and (3) the decline of deciduous oaks in southern Italy and of evergreen oaks in the Iberian peninsula apparently due to the interaction of climate stresses and pests and diseases. However, besides obvious deterioration, changes in environmental factors can provoke situations of more subtle stress. The most sensitive stands are Mediterranean conifer forests and mesophile forests of the Mediterranean-montane plane growing at the edges of the natural ecological distribution. Evergreen sclerophyllous forests appear less sensitive to variations in climatic parameters, since they can adapt quite well to both drought and the action of UV-B rays. Several experiments were carried out to test the sensitivity of Mediterranean forest species to air pollutants. Most of those experiments used seedlings of different species treated with pollutant concentrations too high to be realistic, so it is difficult to derive adequate information on the response of adult trees in field conditions. Ozone has been proved to cause foliar injury in a variety of native forest species in different Southern European countries, while the effects of other pollutants (e.g. nitrogen, sulphur, acidic deposition) are less obvious and likely to be very localized. In the case of ozone, visible symptoms were almost completely missed by large-scale surveys and-at the same time-non-visible symptoms are suspected to be even more widespread than the visible ones. Owing to this and to the complex relationships existing between species sensitivity, ozone exposure and doses, length of the vegetative periods, influence of climatic and edaphic condition on the tree's response, the impacted areas are yet to be identified. Therefore, the large-scale impact of air pollutants on the forests of Southern Europe remains largely unknown, until more specific investigations are carried out.
Keywords: forest conditions; Forest decline; Mediterranean Region; Ozone; pollution climate

Allozyme variation in cork oak ( Quercus suber L.): the role of phylogeography and genetic introgression by other Mediterranean oak species and human activities - Toumi, L; Lumaret, R (TAG Theoretical and Applied Genetics, 1998)
Genetic variation in the cork oak (Quercus suber L.) was investigated using 11 loci from seven enzyme systems in 40 populations sampled over the entire distribution of this species in the western Medi- terranean Basin. Mean heterozygosity values over the polymorphic loci (Ho"0.283), the percentage of poly- morphic populations (M"0.76), and the total genetic diversity (Ht"0.31) from which 11% was accounted for among-population variation, are among the highest recorded in oak species. In contrast to previous results in holm oak (Q. ilex L.), another evergreen species in the same area, cork oak possessed a smaller allele pool and a lower average number of alleles per locus and per population (A"2.0). More particularly, very few low- frequency alleles were observed in cork oak except for eight populations in which allozyme polymorphism at locus Pgi 1, diagnostic between both species, indicates that these low-frequency alleles are introgressed from holm oak. On the basis of the genetic distance esti- mated from allozyme frequencies, 32 of the 40 cork oak populations studied were classiÞed into two very distinct sets which also corresponded to distinct geographic areas. One set gathered together the 18 populations from the Iberian peninsula and two adjac- ent areas in France, i.e. the centre of origin of cork oak, according to paleobotanical data. This set was charac- terized by a larger allele pool, a higher within-popula- tion genetic diversity and a lower di¤erentiation between populations than was observed in the other set, which comprised the populations from North Africa, Sicily, Sardinia, Corsica, continental Italy and the region of Provence (southeastern France). In these Communicated by P. M. A. Tigerstedt L. Toumi1 á R. Lumaret ( ) Centre dÕEcologie Fonctionnelle et Evolutive (C.E.F.E., C.N.R.S.), F-34293, Montpellier Cedex 05, France Present address: 1 Institut Sylvo-Pastoral, 8110 Tabarka, Tunisia more southern and eastern disjunct areas, cork oak migration from Iberia may have occurred at di¤erent periods since the end of the Tertiary. The possible e¤ect of human activity on cork oak genetic structure, i.e. the selection of good-quality cork, acorn over-use for ani- mal food, and even human nutrition, is discussed.
Keywords: allozyme polymorphism; genetic structure; human activity and population; phylogeography; Quercus suber

ANÁLISIS TÉCNICO-ECONÓMICO DE LA ALIMENTACIÓN DEL GANADO VACUNO EN LA DEHESA SALMANTINA - GONZÁLEZ EGUREN, Vicente; Guijarro, Angel Prieto; Revuelta, José Fernandez (6º Congreso de Economía Regional de Castilla y León (Zamora, 1998): "Agricultura y ganadería en Castilla y León", 1998)
El trabajo pretende establecer un balance de la alimentación en las explotaciones de ganado vacuno en sistemas agrosilvopastorales del Centro-Oeste de España, como uno de los elementos reguladores del sistema. Se realiza un balance en términos físicos, económicos y energéticos entre las necesidades del ganado y los aportes complementarios de alimentos externos al sistema. Este balance tiene incidencia en la cuenta de resultados de explotación del sistema y constituye una guía para el análisis del proceso adaptativo de su gestión a corto plazo, y una previsión de la estabilidad a largo plazo.
Keywords: Alimentación; Análisis técnico-económico; Dehesa; Ganado vacuno

Analyse de la réponse de la végétation aux trouées naturelles dans une futaie âgée de Quercus ilexL. en Corse (île Méditerranéenne) - Panaïotis, Christophe; Loisel, Roger; Roux, Maurice (Canadian Journal of Forest Research, 1998)
Green oak (Quercus ilexL.) is the most common forest species growing under Mediterranean climate. Because of important past anthropic perturbations, green oak old-growth forests are very unfrequent and constitute, for that reason, a most interesting domain where to analyze the natural evolution of green oak stands. Such forests exist in Corsica and this study deals with vegetation successions as they occur in naturally occuring gaps. Because of the taxonomic poorness (32 species), two statistical tools (canonical correspondence analysis and random permutations) were used to take into account vegetation spatial structure according to types (herbaceous, shrubby, or arborescent). These statistical analyses show that plant succession does not really exist in gaps of green oak old-growth forests but rather a structural organization of common species found in the maquis. Results support the hypothesis about the internal dynamics of these forests going through a maquis phase.
doi: 10.1139/x98-070

Analysis of dehesas with multiple use. Physical and economic indexes of sustainable management - Garcia, F P; SÁNCHEZ, M E; Diaz, F J M; Vega, A R D (BASIS OF THE QUALITY OF TYPICAL MEDITERRANEAN ANIMAL PRODUCTS, 1998)
The wide surface that dehesas hold in Spain, together with their economic, social and environmental importance, give enough justification to the researchs that widen the scientific knowlege about the economics of dehesa systems. However, the dehesa agroforestry farms do not appear in the different statistical documentary sources of the Agricultural Accounting Net. The lack of technical-economic data about these systems impede neither to observe the effects of the Common Agricultural Policy on the natural environment, nor to know as a whole the dynamics and structure of their flows and the stock of resources and income. This paper deals with the technical and economic management of dehesas in the field of the environmental economics. Its main aim has been to carry out an analytical case study. In order to develop it, four dehesa farms in the Southwest of the Badajoz Province were selected. These farms have collaborated on the development of the Research Project UE CAMAR CT 90-28 ``Technical and economic analysis of dehesa and montado systems{''}. Its importance lies in the basis of the case analysis, with a description of the systems and an identification of the structure and dynamics of their resources, either at physical and economic level.
Keywords: Dehesa; environmental econ; sustainable management

Analysis of dehesas with multiple use. Physical and economic indexes of sustainable management - Garcia, F. P.; Sanchez, M. E.; Diaz, F. J. M.; Vega, A. R. D. (BASIS OF THE QUALITY OF TYPICAL MEDITERRANEAN ANIMAL PRODUCTS, 1998)
The wide surface that dehesas hold in Spain, together with their economic, social and environmental importance, give enough justification to the researchs that widen the scientific knowlege about the economics of dehesa systems. However, the dehesa agroforestry farms do not appear in the different statistical documentary sources of the Agricultural Accounting Net. The lack of technical-economic data about these systems impede neither to observe the effects of the Common Agricultural Policy on the natural environment, nor to know as a whole the dynamics and structure of their flows and the stock of resources and income. This paper deals with the technical and economic management of dehesas in the field of the environmental economics. Its main aim has been to carry out an analytical case study. In order to develop it, four dehesa farms in the Southwest of the Badajoz Province were selected. These farms have collaborated on the development of the Research Project UE CAMAR CT 90-28 ``Technical and economic analysis of dehesa and montado systems{''}. Its importance lies in the basis of the case analysis, with a description of the systems and an identification of the structure and dynamics of their resources, either at physical and economic level.
The following values have no corresponding Zotero field: periodical: BASIS OF THE QUALITY OF TYPICAL MEDITERRANEAN ANIMAL PRODUCTS issue: 90 pub-location: POSTBUS 220, 6700 AE WAGENINGEN, NETHERLANDS
Keywords: Dehesa; environmental econ; sustainable management

Analysis of vegetation response to naturally occurring gaps in old-growth forests of Quercus ilex L. in Corsica - Panaiotis, C; Loisel, R; Roux, M (CANADIAN JOURNAL OF FOREST RESEARCH-REVUE CANADIENNE DE RECHERCHE FORESTIERE, 1998)
Green oak (Quercus ilex L.) is the most common forest species growing under Mediterranean climate. Because of important past anthropic perturbations, green oak old-growth forests are very unfrequent and constitute, for that reason, a most interesting domain where to analyze the natural evolution of green oak stands. Such forests exist in Corsica and this study deals with vegetation successions as they occur in naturally occuring gaps. Because of the taxonomic poorness (32 species), two statistical tools (canonical correspondence analysis and random permutations) were used to take into account vegetation spatial structure according to types (herbaceous, shrubby, or arborescent). These statistical analyses show that plant succession does not really exist in gaps of green oak old-growth forests but rather a structural organization of common species found in the maquis. Results support the hypothesis about the internal dynamics of these forests going through a maquis phase.
Keywords: natural gaps; quercus ilex forest; spatial structure; vegetation succession

Analysis of vegetation response to naturally occurring gaps in old-growth forests of Quercus ilex L. in Corsica - Panaiotis, C.; Loisel, R.; Roux, M. (CANADIAN JOURNAL OF FOREST RESEARCH-REVUE CANADIENNE DE RECHERCHE FORESTIERE, 1998)
Green oak (Quercus ilex L.) is the most common forest species growing under Mediterranean climate. Because of important past anthropic perturbations, green oak old-growth forests are very unfrequent and constitute, for that reason, a most interesting domain where to analyze the natural evolution of green oak stands. Such forests exist in Corsica and this study deals with vegetation successions as they occur in naturally occuring gaps. Because of the taxonomic poorness (32 species), two statistical tools (canonical correspondence analysis and random permutations) were used to take into account vegetation spatial structure according to types (herbaceous, shrubby, or arborescent). These statistical analyses show that plant succession does not really exist in gaps of green oak old-growth forests but rather a structural organization of common species found in the maquis. Results support the hypothesis about the internal dynamics of these forests going through a maquis phase.
The following values have no corresponding Zotero field: pub-location: RESEARCH JOURNALS, MONTREAL RD, OTTAWA, ONTARIO K1A 0R6, CANADA publisher: NATL RESEARCH COUNCIL CANADA
Keywords: natural gaps; quercus ilex forest; spatial structure; vegetation succession

Anaphylactic reaction to ingestion of Quercus ilex acorn nut - Vega; DomÍnguez; Cosmes; MartÍnez; BartolomÉ, B; Palacios; Vega, a; Domínguez, C; Cosmes, P; Martínez, a; BartolomÉ, B; Martínez, J; et al. (Clinical & Experimental Allergy, 1998)
Background A patient experienced an anaphylactic reaction after eating acorn nuts, fruit of the holm oak (Quercus ilex), one of the most abundant trees in Spain. Several urticaria episodes upon ingestion of peanuts were also referred. Objective To assess the hypersensitivity reaction to acorn and to characterize the allergenic proteins involved. Methods Cutaneous tests were performed using the skin-prick technique, using a large variety of grass, tree and weed pollens as well as fresh nuts and nut extracts. Specific IgE determination was assessed by RAST. IgE binding bands were determined by SDS-PAGE immunoblotting. Results Skin-prick tests were strongly positive with acorn and peanut. Olea europaea, Quercus alba, Quercus ilex and grass pollens also elicited a weal higher than negative control. Patient serum had measurable levels of IgE antibodies especially to acorn, peanut and grass pollens. Only one protein band, of 17.9 kDa molecular mass, showed IgE-binding properties in the acorn extract. The possible homology of this strong allergenic protein with the group 1 tree pollen allergens was evidenced by the partial inhibition of the western blot with Bet v 1. Conclusions We present a case of anaphylaxis to acorn ingestion as demonstrated by in vivo and in vitro results. A 17.9 kDa IgE-binding band, showing some homology to group 1 pollen tree allergens, was recognized by patient serum.
Keywords: acorn allergens; Anaphylaxis; Anaphylaxis: drug therapy; Anaphylaxis: etiology; Bet v 1; Cross Reactions; Electrophoresis; Food Hypersensitivity; Food Hypersensitivity: drug therapy; Food Hypersensitivity: etiology; Humans; Immunoblotting; Immunoglobulin E; Immunoglobulin E: blood; Male; Middle Aged; nut allergy; Nuts; Nuts: adverse effects; Nuts: immunology; Polyacrylamide Gel; Quercus ilex allergy; Radioallergosorbent Test; Skin Tests

Anaphylactic reaction to ingestion of Quercus ilex acorn nut - Vega; DomÍnguez; Cosmes; MartÍnez; BartolomÉ, B.; Palacios; Vega, a; Domínguez, C.; Cosmes, P.; Martínez, a; BartolomÉ, B.; Martínez, J.; et al. (Clinical & Experimental Allergy, 1998)
Background A patient experienced an anaphylactic reaction after eating acorn nuts, fruit of the holm oak (Quercus ilex), one of the most abundant trees in Spain. Several urticaria episodes upon ingestion of peanuts were also referred. Objective To assess the hypersensitivity reaction to acorn and to characterize the allergenic proteins involved. Methods Cutaneous tests were performed using the skin-prick technique, using a large variety of grass, tree and weed pollens as well as fresh nuts and nut extracts. Specific IgE determination was assessed by RAST. IgE binding bands were determined by SDS-PAGE immunoblotting. Results Skin-prick tests were strongly positive with acorn and peanut. Olea europaea, Quercus alba, Quercus ilex and grass pollens also elicited a weal higher than negative control. Patient serum had measurable levels of IgE antibodies especially to acorn, peanut and grass pollens. Only one protein band, of 17.9 kDa molecular mass, showed IgE-binding properties in the acorn extract. The possible homology of this strong allergenic protein with the group 1 tree pollen allergens was evidenced by the partial inhibition of the western blot with Bet v 1. Conclusions We present a case of anaphylaxis to acorn ingestion as demonstrated by in vivo and in vitro results. A 17.9 kDa IgE-binding band, showing some homology to group 1 pollen tree allergens, was recognized by patient serum.
The following values have no corresponding Zotero field: publisher: Blackwell Science Ltd, UK accession-num: 9677139
Keywords: acorn allergens; Anaphylaxis; Anaphylaxis: drug therapy; Anaphylaxis: etiology; Bet v 1; Cross Reactions; Electrophoresis; Food Hypersensitivity; Food Hypersensitivity: drug therapy; Food Hypersensitivity: etiology; Humans; Immunoblotting; Immunoglobulin E; Immunoglobulin E: blood; Male; Middle Aged; nut allergy; Nuts; Nuts: adverse effects; Nuts: immunology; Polyacrylamide Gel; Quercus ilex allergy; Radioallergosorbent Test; Skin Tests

Antioxidative systems, pigment and protein contents in leaves of adult mediterranean oak species (Quercus pubescens and Q. ilex) with lifetime exposure to elevated CO2 - Schwanz, P; Polle, A (New Phytologist, 1998)
The aim of the present study was to investigate the effects of elevated CO2 on the antioxidative systems and the contents of pigments, soluble protein and lipid peroxidation in leaves of adult oaks, Quercus pubescens and Quercus ilex, grown at naturally enriched CO2 concentrations. For this purpose, a field study was conducted at two CO2 springs in Central Italy. Measurements of the pre-dawn water potentials indicated less drought stress in trees close to CO2 springs than in those grown at ambient CO2 concentrations. Most leaf constituents investigated showed significant variability between sampling dates, species and sites. The foliar contents of protein and chlorophylls were not affected in trees grown close to the CO2 vents compared with those in ambient conditions. Increases in glutathione and other soluble thiols were observed, but these responses might have been caused by a low pollution of the vents with sulphurous gases. At CO2 vents, glutathione reductase was unaffected, and superoxide dismutase activity was significantly diminished, in both species. Generally, the activities of catalase, guaiacol peroxidase and ascorbate peroxidase as well as the sum of dehydroascorbate and ascorbate were decreased in leaves from trees grown in naturally CO2-enriched environments compared with those grown at ambient CO2 concentrations. The reduction in protective enzymes did not result in increased lipid peroxidation, but increased monodehydroascorbate radical reductase and dehydroascorbate reductase activities found in leaves of Q. pubescens suggest that the smaller pool of ascorbate was subjected to higher turnover rates. These data show that changes in leaf physiology persist, even after lifetime exposure to enhanced atmospheric CO2. The results suggest that the down-regulation of protective systems, which has also previously been found in young trees or seedlings under controlled exposure to elevated CO2 concentrations, might reflect a realistic response of antioxidative defences in mature trees in a future high-CO2 world.
Keywords: antioxidants; carbon dioxide enrichment; Drought; Oxidative stress; Quercus spp. (holm oak - white oak)

On the applicability of Landsat TM images to Mediterranean forest inventories - Salvador, Raymond; Pons, Xavier (Forest Ecology and Management, 1998)
Landsat TM images were used in combination with field measurements to create models for Mediterranean forests. Radiometric data from those images were related to field data from a forest inventory by means of regression analysis. Trials using plots with radiometrically homogeneous surroundings were carried out to evaluate the effect of high spatial heterogeneity frequently found in Mediterranean forests. Simple regression models were found to be consistent with the expected radiometric response of vegetation, and most of the multiple regression models fitted the observations sufficiently in order to make quantitative predictions for field variables from the remote sensing images. According to this study, however, these models should be regarded as exploratory models rather than fully operational ones. Spatially and non-spatially related factors are suggested as causes of the remaining dispersion of models created.
Keywords: forest quantitative variables; predictive models; radiometric response; spatial heterogeneity

Application of an Electronic Aroma Sensing System to Cork Stopper Quality Control - Rocha, S; Delgadillo, I; Ferrer Correia, A J; Barros, A; Wells, P (Journal of Agricultural and Food Chemistry, 1998)
Cork odors were characterized using an electronic aroma sensing system. The electronic system is a compact, benchtop instrument comprising a sensor array, signal processing hardware, a measurement algorithm, and a pattern classification system. The sensor array responds to the presence of aroma volatile compounds by changes in their electrical properties. Resistance changes are displayed as a histogram, which is a fingerprint of the aroma being analyzed. Five different cork odors were studied: NE, which is considered as standard cork odor; CO, exhibiting the pleasant boiled cork odor (it is also considered as a good odor); PO, corresponding to rotten odor; and B and BO, representing moldy and very intensely moldy odors, respectively. This electronic aroma sensing system could discriminate quickly and objectively between acceptable odor and the unacceptable taint. Characterization and selection of a subset of sensors were performed. A relation between sensors and specific odors was established. The system, once trained with representative acceptable and unacceptable samples, could be used as a simple quality control tool and incorporated into the normal quality control procedures for each batch of product, by providing real-time analysis of a sample overall aroma.
doi: 10.1021/jf970259+
Keywords: Cork stoppers; electronic aroma sensing system; off-flavors; quality control; “standard” aroma

Biogenic emissions by oak trees common to Mediterranean ecosystems - Simon, V; Dutaur, L (Environmental Monitoring and Assessment, 1998)
An inventory describing the fluxes of volatile organic compounds (VOCs), isoprene and monoterpenes, and other VOCs (OVOCs) from the biosphere to the atmosphere, has been constructed within the framework of the ESCOMPTE project (fiEld experimentS to COnstrain Models of atmospheric Pollution and Transport of Emissions). The area concerned, located around Berre-Marseilles, is a Mediterranean region frequently subject to high ozone concentrations. The inventory has been developed using a fine scale land use database for the year 1999, forest composition statistics, emission potentials from individual plant species, biomass distribution, temperature and light intensity. The seasonal variations in emission potentials and biomass were also taken into account. Hourly meteorological data for 1999 were calculated from ALADIN data and these were used to predict the hourly isoprene, monoterpene and OVOC fluxes for the area on a 1 km × 1 km spatial grid. Estimates of annual biogenic isoprene, monoterpene and OVOC fluxes for the reference year 1999 were 20.6, 38.9 and 13.3 kt, respectively, Quercus pubescens, Quercus ilex, Pinus halepensis and garrigue vegetation are the dominant emitting species of the area. VOC emissions from vegetation in this region contribute approximately 94% to the NMVOC (non-methane volatile organic compounds) of natural origin and are of the same order of magnitude as NMVOC emissions from anthropogenic sources. These results complete the global ESCOMPTE database needed to make an efficient strategy for tropospheric ozone reduction policy.
Keywords: biogenic VOCS; Emission inventory; isoprene; Mediterranean ecosystems; Monoterpenes (citation)

Biogenic emissions by oak trees common to Mediterranean ecosystems - Simon, V.; Dutaur, L. (Environmental Monitoring and Assessment, 1998)
An inventory describing the fluxes of volatile organic compounds (VOCs), isoprene and monoterpenes, and other VOCs (OVOCs) from the biosphere to the atmosphere, has been constructed within the framework of the ESCOMPTE project (fiEld experimentS to COnstrain Models of atmospheric Pollution and Transport of Emissions). The area concerned, located around Berre-Marseilles, is a Mediterranean region frequently subject to high ozone concentrations. The inventory has been developed using a fine scale land use database for the year 1999, forest composition statistics, emission potentials from individual plant species, biomass distribution, temperature and light intensity. The seasonal variations in emission potentials and biomass were also taken into account. Hourly meteorological data for 1999 were calculated from ALADIN data and these were used to predict the hourly isoprene, monoterpene and OVOC fluxes for the area on a 1 km × 1 km spatial grid. Estimates of annual biogenic isoprene, monoterpene and OVOC fluxes for the reference year 1999 were 20.6, 38.9 and 13.3 kt, respectively, Quercus pubescens, Quercus ilex, Pinus halepensis and garrigue vegetation are the dominant emitting species of the area. VOC emissions from vegetation in this region contribute approximately 94% to the NMVOC (non-methane volatile organic compounds) of natural origin and are of the same order of magnitude as NMVOC emissions from anthropogenic sources. These results complete the global ESCOMPTE database needed to make an efficient strategy for tropospheric ozone reduction policy.
Keywords: biogenic VOCS; Emission inventory; isoprene; Mediterranean ecosystems; Monoterpenes (citation)

Changes in Tannic Composition of Reproduction Cork Quercus suber throughout Industrial Processing - Cadahía, Estrella; Conde, Elvira; Fernández de Simón, Brígida; García-Vallejo, María Concepción (Journal of Agricultural and Food Chemistry, 1998)
Tannic composition was studied in reproduction cork samples from three different trees of Spanish Quercus suber and at different industrial processing stages. The ellagitannins, roburins A and E, grandinin, vescalagin, and castalagin, were identified and quantified by HPLC. Global evaluations of tannins were also carried out, using classical chemical methods. The group of hydrolyzable tannins was the most abundant in the tannic extract in all samples; among them, castalagin was the main component, followed by vescalagin, grandinin, roburin E, and, to a much lesser extent, roburin A. The changes in tannic composition throughout the industrial processing are mainly related to the boiling process and are more pronounced in total phenol and proanthocyanidin contents than in individual ellagitannins content. Vescalagin and roburins A and E were selected as those variables that provided the greatest discrimination among stages. Important differences in the ellagitannin contents were observed among the trees studied, all of the ellagitannins being discriminant variables in this case. Keywords: Quercus suber; cork; tannins; ellagitannins; proanthocyanidins; polyphenols; high-performance liquid chromatography
doi: 10.1021/jf9709360doi: 10.1021/jf9709360The following values have no corresponding Zotero field: publisher: American Chemical Society
Keywords: Cork; ellagitannins; high performance liquid chromatography; polyphenols; proanthocyanidins; Quercus suber; Tannins

Changes in Tannic Composition of Reproduction Cork Quercus suber throughout Industrial Processing - Cadahía, Estrella; Conde, Elvira; Fernández de Simón, Brígida; García-Vallejo, María Concepción (Journal of Agricultural and Food Chemistry, 1998)
Tannic composition was studied in reproduction cork samples from three different trees of Spanish Quercus suber and at different industrial processing stages. The ellagitannins, roburins A and E, grandinin, vescalagin, and castalagin, were identified and quantified by HPLC. Global evaluations of tannins were also carried out, using classical chemical methods. The group of hydrolyzable tannins was the most abundant in the tannic extract in all samples; among them, castalagin was the main component, followed by vescalagin, grandinin, roburin E, and, to a much lesser extent, roburin A. The changes in tannic composition throughout the industrial processing are mainly related to the boiling process and are more pronounced in total phenol and proanthocyanidin contents than in individual ellagitannins content. Vescalagin and roburins A and E were selected as those variables that provided the greatest discrimination among stages. Important differences in the ellagitannin contents were observed among the trees studied, all of the ellagitannins being discriminant variables in this case. Keywords: Quercus suber; cork; tannins; ellagitannins; proanthocyanidins; polyphenols; high-performance liquid chromatography
doi: 10.1021/jf9709360
Keywords: Cork; ellagitannins; high performance liquid chromatography; polyphenols; proanthocyanidins; Quercus suber; Tannins

Changes in terpene content and emission in potted Mediterranean woody plants under severe drought - Llusia, J.; Penuelas, J. (Canadian Journal of Botany, 1998)
Terpene concentration and emission were studied in potted plants of some of the most common Mediterranean woody species (Pinus halepensis L., Pistacia lentiscus L., Cistus albidus L., Cistus monspeliensis L., Quercus ilex L., Quercus coccifera L., Phillyrea latifolia L., Phillyrea angustifolia L., and Arbutus unedo L.) under irrigation and under severe drought conditions that dropped relative water content to a range between 40% in Q. ilex and 85% in Phillyrea latifolia after withholding watering for one dry summer week. Terpene concentrations were detected in Pinus halepensis, Pistacia lentiscus, C. albidus, and C. monspeliensis, and they increased after withholding watering except in C. albidus. Terpene emission was detected in all species except Phillyrea angustifolia and A. unedo. Pinus halepensis showed the highest diurnal terpene emission rates of 86 µg·g-1 dry wt.·h-1 followed by C. albidus, Pistacia lentiscus, Q. ilex, Q. coccifera, Phillyrea latifolia, and C. monspeliensis (4 µg·g-1 dry wt.·h-1). Emitted terpenes represented from 0.33% of C fixed in C. monspeliensis to 10% in C. albidus. All species severely decreased their terpene emission rates under severe drought conditions. Emission by terpene-storing species (e.g., Pinus halepensis) was more related to temperature than in nonstoring species (e.g., Q. ilex), which showed emission relationships with photosynthetic rates. The monoterpenes alpha-pinene, beta-pinene, beta-phellandrene, and limonene and the sesquiterpene caryophyllene were the most abundant terpenes stored and emitted by these Mediterranean plant species.Key words: drought, Mediterranean conditions, terpene concentration, terpene emission, woody plants
doi: 10.1139/b98-141doi: 10.1139/b98-141The following values have no corresponding Zotero field: publisher: NRC Research Press
Keywords: Drought; Mediterranean conditions; terpene concentration; Terpene emission; Woody plants

Changes in terpene content and emission in potted Mediterranean woody plants under severe drought - Llusia, J; Penuelas, J (Canadian Journal of Botany, 1998)
Terpene concentration and emission were studied in potted plants of some of the most common Mediterranean woody species (Pinus halepensis L., Pistacia lentiscus L., Cistus albidus L., Cistus monspeliensis L., Quercus ilex L., Quercus coccifera L., Phillyrea latifolia L., Phillyrea angustifolia L., and Arbutus unedo L.) under irrigation and under severe drought conditions that dropped relative water content to a range between 40% in Q. ilex and 85% in Phillyrea latifolia after withholding watering for one dry summer week. Terpene concentrations were detected in Pinus halepensis, Pistacia lentiscus, C. albidus, and C. monspeliensis, and they increased after withholding watering except in C. albidus. Terpene emission was detected in all species except Phillyrea angustifolia and A. unedo. Pinus halepensis showed the highest diurnal terpene emission rates of 86 µg·g-1 dry wt.·h-1 followed by C. albidus, Pistacia lentiscus, Q. ilex, Q. coccifera, Phillyrea latifolia, and C. monspeliensis (4 µg·g-1 dry wt.·h-1). Emitted terpenes represented from 0.33% of C fixed in C. monspeliensis to 10% in C. albidus. All species severely decreased their terpene emission rates under severe drought conditions. Emission by terpene-storing species (e.g., Pinus halepensis) was more related to temperature than in nonstoring species (e.g., Q. ilex), which showed emission relationships with photosynthetic rates. The monoterpenes alpha-pinene, beta-pinene, beta-phellandrene, and limonene and the sesquiterpene caryophyllene were the most abundant terpenes stored and emitted by these Mediterranean plant species.Key words: drought, Mediterranean conditions, terpene concentration, terpene emission, woody plants
doi: 10.1139/b98-141
Keywords: Drought; Mediterranean conditions; terpene concentration; Terpene emission; Woody plants

Chemical Characterization of Reproduction Cork from Spanish Quercus Suber - Conde, Elvira; Cadahía, Estrella; Garcia-Vallejo, Maria Conceptión; Gonźalez-Adrados, José Ramón (Journal of Wood Chemistry and Technology, 1998)
Abstract The chemical composition of Quercus suber reproduction cork was studied in planks from three different trees at different stages of their industrial processing and in samples collected in seven locations in the three main Spanish production areas. Extracts in chloroform, methanol and water, ne[ugrave]tral and acid fractions of waxes, suberin, lignin, holocellulose and pentosans, and polyphenols (low molecular weight polyphenols and tannins), were quantified. Suberin was the main component in all the samples, followed by lignin and holocellulose in lower concentrations. The most affected variables throughout the industrial processing were: lignin, chloroform and water extracts and the acid fraction of waxes. These variables did not allow one to distinguish the studied trees, which are differentiated by the percentages of methanol extracts, the tannic fraction of polyphenols, the free of suberin residue and the holocellulose content. Four variables were selected as those which provided the greatest discrimination among provenances: methanol extract, low molecular weight polyphenols, desuberinized residue and acid fraction of waxes. However, the studied populations can not be clearly distinguished by their chemical composition and no relationship was found between geographical proximity of their provenances and chemical resemblance.
doi: 10.1080/02773819809349592doi: 10.1080/02773819809349592The following values have no corresponding Zotero field: publisher: Taylor & Francis
Keywords: chemical composition; Cork; suberin; waxes (voyant)

Chemical Characterization of Reproduction Cork from Spanish Quercus Suber - Conde, Elvira; Cadahía, Estrella; Garcia-Vallejo, Maria Conceptión; Gonźalez-Adrados, José Ramón (Journal of Wood Chemistry and Technology, 1998)
Abstract The chemical composition of Quercus suber reproduction cork was studied in planks from three different trees at different stages of their industrial processing and in samples collected in seven locations in the three main Spanish production areas. Extracts in chloroform, methanol and water, ne[ugrave]tral and acid fractions of waxes, suberin, lignin, holocellulose and pentosans, and polyphenols (low molecular weight polyphenols and tannins), were quantified. Suberin was the main component in all the samples, followed by lignin and holocellulose in lower concentrations. The most affected variables throughout the industrial processing were: lignin, chloroform and water extracts and the acid fraction of waxes. These variables did not allow one to distinguish the studied trees, which are differentiated by the percentages of methanol extracts, the tannic fraction of polyphenols, the free of suberin residue and the holocellulose content. Four variables were selected as those which provided the greatest discrimination among provenances: methanol extract, low molecular weight polyphenols, desuberinized residue and acid fraction of waxes. However, the studied populations can not be clearly distinguished by their chemical composition and no relationship was found between geographical proximity of their provenances and chemical resemblance.
doi: 10.1080/02773819809349592
Keywords: chemical composition; Cork; suberin; waxes (voyant)

The chemical composition of dust transported in red rains—its contribution to the biogeochemical cycle of a holm oak forest in Catalonia (Spain) - Avila, a; Alarcon, M; Queralt, I (Atmospheric Environment, 1998)
The chemistry of North African dust reaching NE Spain with red rains is here described to (1) characterize the red dust elemental composition, (2) analyze the relative contribution of dissolved and particulate forms to the total element inputs for the period 1983–1994, and (3) study the role of the particulate and dissolved inputs in red rains to the forest nutrient cycle. Five dust samples, obtained from the filtration of five red rain events, have been considered as representative of the dust reaching NE Spain as they include dust from the main source regions in North Africa. Enrichment factors were lower than four for all elements and samples, indicating the crustal character of the red dusts and their scarce mixing with anthropogenic pollutants. Back trajectory analysis of the red rain air masses computed at various isentropic surfaces showed northward fluxes at all altitudes in four out of five events. The remaining event, which presented a lower layer from European origin contacting upper layers of North African provenance, had higher trace metal concentrations in the dust (still lower than reported values for the circum-Mediterranean area) and higher S and N concentrations in dissolved form. The occurrence of red rains introduced high interannual variability in the input fluxes for the major elements. Phosphorus inputs occurred mostly in particulate form linked to red dust deposition. Red dust particulate inputs were also important for K+ and Mg2+. For Ca2+, dissolved inputs in red rains equalled and sometimes overuled particulate inputs in red dust, due to the calcite dissolution. Sodium and S inputs in red rains were mostly in dissolved form. The amounts of base cations delivered by red rains are important contributors to the holm oak forest needs at Montseny, by providing 27% of K+, 45% of Ca2+ and 84% of Mg2+ fluxes needed for the above ground biomass annual increment. For Ca2+ this is specially relevant because of the calcium-poor lithology of the site
Keywords: aerosol composition; Back trajectories; forest biogeochemistry; nutrient inputs; Saharan dust

Chlorophyll degradation effected by lichen substances - Bouaid, K.; Vicente, C. (ANNALES BOTANICI FENNICI, 1998)
Epiphytic lichens can exert some negative actions on trees, since they penetrate to different degrees into several tissues of the phytophore. Evernia prunastri (L.) Ach. hyphae progress into xylem vessels of Fagus sylvatica, Quercus pyrenaica and Betula alba. This is on the basis of a mechanism through which Lichens inject metabolic inhibitors in the xylem vessels, and, after their translocation in the xylem sap, they reach different organs of the phytophore and produce defoliation. In this report, we have noted that usnic acid is more impermeant than atranorin through the chloroplast membrane of Quercus rotundifolia leaves. On the other hand, we have also noted the degradation of chlorophyll in response to Lichen substances.
The following values have no corresponding Zotero field: pub-location: UNIV HELSINKI P O BOX 17 (P. RAUTATIEKATU 13), FIN-00014 HELSINKI, FINLAND publisher: FINNISH ZOOLOGICAL BOTANICAL PUBLISHING BOARD
Keywords: chlorophyll degradation; Evernia prunastri; lichen phenols; Quercus rotundifolia

Chlorophyll degradation effected by lichen substances - Bouaid, K; Vicente, C (ANNALES BOTANICI FENNICI, 1998)
Epiphytic lichens can exert some negative actions on trees, since they penetrate to different degrees into several tissues of the phytophore. Evernia prunastri (L.) Ach. hyphae progress into xylem vessels of Fagus sylvatica, Quercus pyrenaica and Betula alba. This is on the basis of a mechanism through which Lichens inject metabolic inhibitors in the xylem vessels, and, after their translocation in the xylem sap, they reach different organs of the phytophore and produce defoliation. In this report, we have noted that usnic acid is more impermeant than atranorin through the chloroplast membrane of Quercus rotundifolia leaves. On the other hand, we have also noted the degradation of chlorophyll in response to Lichen substances.
Keywords: chlorophyll degradation; Evernia prunastri; lichen phenols; Quercus rotundifolia

Climatic classification and ordination of the Spanish Sistema Central: relationships with potential vegetation - Gavilán, R G; Fernández-González, F; Blasi, C (Plant Ecology, 1998)
Monthly precipitation and monthly mean temperature records from 255 meteorological stations in Central Spain (Spanish Sistema Central) were analyzed by cluster and principal component analyses. Classiﬁcation separated 14 groups according to altitude, geographical distribution, as well as the combination of rainfall and temperature. The ﬁrst cluster emerged as signiﬁcantly higher and colder than the second. Then, two ordinations were carried out: one for the 14 groups extracted from the classiﬁcation and a second for the total station pool. The second ordination was compared with potential natural vegetation data taken around each station. The ﬁrst ordination summarized the principal climatic characteristics of the Spanish Sistema Central: its behaviour is that of a typical Mediterranean mountainous territory combining summer aridity and variation of temperature with altitude and the inﬂuence of winter winds. The ordination of all stations reﬂected a thermal, rainfall and summer aridity gradient. Meteorological stations situated at the highest altitude or with highest precipitation records characterized by scrub communities or pine woods and Quercus pyrenaica forests, appeared well-separated along the ﬁrst two axes. Only the most thermophilous Q. rotundifolia associations could be clearly separated. The fourth axis was useful in clarifying some vegetation overlap of deciduous and sclerophyllous forests, along an east-west summer aridity gradient.
Keywords: climate; cluster analysis; potential vegetation; Precipitation; Principal component analysis; Spain; Temperature

Collembola populations under sclerophyllous coppices in Provence (France): comparison between two types of vegetation, Quercus ilex L. and Quercus coccifera L. - Cortet, Jérôme; Poinsot-Balaguer, Nicole (Acta Oecologica, 1998)
A comparative analysis of soil Collembola using two types of sclerophyllous vegetation (Quercus ilex and Quercus cocc@ru) was performed at a calcareous site in Provence (France). Collembola populations were examined over a one-year period (1 I successive months) in three different soil layers. Although no statistically significant differences could be observed for Collembola abundance and diversity, multivariate analyses (FCA) differentiated the two coppices. Phenologies of some species showed specific responses to the microclimate induced by edaphic conditions. Even though the two coppices were sclerophyllous, the structure of each vegetation, the quantity and quality of litter, which were dif- ferent, could influence environmental conditions and thus the dynamics of collembolan populations.
Keywords: Collembola; litter decomposition; Phenology; Quercus coccifera; Quercus ilex

Collembola populations under sclerophyllous coppices in Provence (France): comparison between two types of vegetation, Quercus ilex L. and Quercus coccifera L. - Cortet, Jérôme; Poinsot-Balaguer, Nicole (Acta Oecologica, 1998)
A comparative analysis of soil Collembola using two types of sclerophyllous vegetation (Quercus ilex and Quercus cocc@ru) was performed at a calcareous site in Provence (France). Collembola populations were examined over a one-year period (1 I successive months) in three different soil layers. Although no statistically significant differences could be observed for Collembola abundance and diversity, multivariate analyses (FCA) differentiated the two coppices. Phenologies of some species showed specific responses to the microclimate induced by edaphic conditions. Even though the two coppices were sclerophyllous, the structure of each vegetation, the quantity and quality of litter, which were dif- ferent, could influence environmental conditions and thus the dynamics of collembolan populations.
Keywords: Collembola; litter decomposition; Phenology; Quercus coccifera; Quercus ilex

Comparaison des effets de la contrainte hydrique sur la croissance, la conductance stomatique et la photosynthèse de jeunes plants de chênes méditerranéens (Quercus suber, Q. faginea, Q. coccifera) en Tunisie - Ksontini, Mustapha; Louguet, Philippe; Laffray, Daniel; Rejeb Nejib, Mohamed (Ann. For. Sci., 1998)
Comparison of the water stress effects on stomatal conductance, photosynthesis and growth of Mediterannean oak seedlings (Quercus suber L., Q. faginea, Q. coccifera) in Tunisia. Two evergreen oaks (Quercus suber L., Q. coccifera) and one deciduous oak (Q. faginea Willd.) were subjected to drought in a nursery in Tunis. Six- and 18-month-old seedlings were grown in pots and underwent two cycles of drought by withholding water supply. Predawn and midday leaf water potentials, stomatal conductance, photosynthesis and plant transpiration were recorded. An analysis of root and shoot biomass, shoot-to-root ratio and leaf area was also performed. Our results showed a higher reduction of shoot-to-root biomass ratio of Q. faginea compared to Q. coccifera under water limitation. The stomatal conductance decrease, related to the decrease of predawn leaf water potential, occurred earlier with Q. faginea. Q. coccifera kept its stomata partly open at a water potential of -3.0 MPa. Q. suber behaved somewhat intermediate. Photosynthesis and stomatal conductance were correlated and showed a midday depression. Our results indicate that more ecophysiological studies are required to take into account seedling and leaf ages during the juvenile stage for a better understanding of the water stress responses of these species and regeneration problems of oaks.
Keywords: Drought; photosynthesis; Quercus coccifera; Quercus faginea; Quercus suber; Stomatal conductance

Comparative field study of spring and summer leaf gas exchange and photobiology of the mediterranean trees Quercus ilex and Phillyrea latifolia - Penuelas, J; Filella, I; Llusia, J; Siscart, D; Piñol, J (Journal of Experimental Botany, 1998)
Summer-induced changes in gas exchange, fluorescence and reflectance were measured on leaves of two co-occurring Mediterranean small trees, Quercus ilex and Phillyrea latifolia, in May, June and July 1996 in Central Catalonia (NE Spain). The humid 1996 summer only produced mild water stress conditions. However, photosynthesis (A) and stomatal conductance (gs) decreased in June and July in both species. In June P. latifolia had higher net photosynthetic rates and lower stomatal conductances than Q. ilex, thus exhibiting higher instantaneous plant water use efficiencies. In agreement with these results, the photo-chemical reflectance index (PRI, calculated as (R570-R531)/(R531+R570)) of P. latifolia was lower, suggesting a possible lower xanthophyll de-epoxidation state. However, P. latifolia had lower ΔF/F′ and therefore a lower electron transport rate (ETR). The behaviour of PRI confirmed previous studies indicating a strong relationship between PRI, ΔF/F′ , and photosynthetic radiation-use efficiency (PRUE). PRI offers a simple, portable means of assessing PRUE with the potential for remote sensing applications. Finally, the possible ecological consequences of these results on the behaviour of the two species studied under the predicted warmer and drier conditions of global change are discussed.
10.1093/jxb/49.319.229
Keywords: fluorescence; intrinsic water use efficiency; net photosynthetic rates; phillyrea latifolia; photochemical efficiency; photochemical reflectance index; photosynthetic radiation-use-efficiency; Quercus ilex; reflectance; Stomatal conductance; summer; water index

Comparative field study of spring and summer leaf gas exchange and photobiology of the mediterranean trees Quercus ilex and Phillyrea latifolia - Penuelas, J.; Filella, I.; Llusia, J.; Siscart, D.; Piñol, J. (Journal of Experimental Botany, 1998)
Summer-induced changes in gas exchange, fluorescence and reflectance were measured on leaves of two co-occurring Mediterranean small trees, Quercus ilex and Phillyrea latifolia, in May, June and July 1996 in Central Catalonia (NE Spain). The humid 1996 summer only produced mild water stress conditions. However, photosynthesis (A) and stomatal conductance (gs) decreased in June and July in both species. In June P. latifolia had higher net photosynthetic rates and lower stomatal conductances than Q. ilex, thus exhibiting higher instantaneous plant water use efficiencies. In agreement with these results, the photo-chemical reflectance index (PRI, calculated as (R570-R531)/(R531+R570)) of P. latifolia was lower, suggesting a possible lower xanthophyll de-epoxidation state. However, P. latifolia had lower ΔF/F′ and therefore a lower electron transport rate (ETR). The behaviour of PRI confirmed previous studies indicating a strong relationship between PRI, ΔF/F′ , and photosynthetic radiation-use efficiency (PRUE). PRI offers a simple, portable means of assessing PRUE with the potential for remote sensing applications. Finally, the possible ecological consequences of these results on the behaviour of the two species studied under the predicted warmer and drier conditions of global change are discussed.
10.1093/jxb/49.319.22910.1093/jxb/49.319.229
Keywords: fluorescence; intrinsic water use efficiency; net photosynthetic rates; phillyrea latifolia; photochemical efficiency; photochemical reflectance index; photosynthetic radiation-use-efficiency; Quercus ilex; reflectance; Stomatal conductance; summer; water index

Comparative study of Spanish and Italian terrestrial small mammal coenoses from different biotopes in Mediterranean peninsular tip regions - Cagnin, M.; Moreno, S.; Aloise, G.; Garofalo, G.; Villafuerte, R.; Gaona, P.; Cristaldi, M. (Journal of Biogeography, 1998)
A comparison of terrestrial small mammal coenoses belonging to nine different biotopes in the tips of the Iberian and Italian peninsulas was carried out using the pitfall trapping method. The influence of both habitat type and peninsular effect on composition of small mammal coenoses was analysed. In Southern Italy, 203 specimens belonging to seven species were trapped: Suncus etruscus (Savi, 1822), Crocidura suaveolens (Pallas, 1811), C. leucodon (Hermann, 1780), Microtus savii (de Sélys-Longchamps, 1838), Apodemus sylvaticus (L., 1758), A. flavicollis (Melchior, 1834) and Mus musculus domesticus Schwarz & Schwarz, 1943. In Southern Spain 428 specimens belonging to five species were trapped: Suncus etruscus, Crocidura russula (Hermann, 1780), Microtus duodecimcostatus (de Sélys-Longchamps, 1839), Apodemus sylvaticus and Mus spretus Lataste, 1883. The relative density of small mammals occurring in the nine Spanish sampling stations was twice that recorded in the Italian stations; however the number of species recorded in the different biotopes show similar mean values, ranging from three to five in Andalusia and from three to six in Calabria. Apodemus sylvaticus was the dominant species in the Calabrian stations, whereas Crocidura russula prevailed in Andalusia. The biotic diversity values are very similar in the Calabrian and Andalusian biotopes. By contrast, the Insectivora/Rodentia ratio was always higher in Andalusia. The more xerophytic biotopes showed greater similarities between the communities in Southern Spain and Southern Italy, while the cooler biotopes differed between these two peninsulas.
The following values have no corresponding Zotero field: publisher: Blackwell Science Ltd
Keywords: habitat type; Italy; peninsular effect; sclerophyll biome; Small mammal communities; Spain

Comparative study of Spanish and Italian terrestrial small mammal coenoses from different biotopes in Mediterranean peninsular tip regions - Cagnin, M; Moreno, S; Aloise, G; Garofalo, G; Villafuerte, R; Gaona, P; Cristaldi, M (Journal of Biogeography, 1998)
A comparison of terrestrial small mammal coenoses belonging to nine different biotopes in the tips of the Iberian and Italian peninsulas was carried out using the pitfall trapping method. The influence of both habitat type and peninsular effect on composition of small mammal coenoses was analysed. In Southern Italy, 203 specimens belonging to seven species were trapped: Suncus etruscus (Savi, 1822), Crocidura suaveolens (Pallas, 1811), C. leucodon (Hermann, 1780), Microtus savii (de Sélys-Longchamps, 1838), Apodemus sylvaticus (L., 1758), A. flavicollis (Melchior, 1834) and Mus musculus domesticus Schwarz & Schwarz, 1943. In Southern Spain 428 specimens belonging to five species were trapped: Suncus etruscus, Crocidura russula (Hermann, 1780), Microtus duodecimcostatus (de Sélys-Longchamps, 1839), Apodemus sylvaticus and Mus spretus Lataste, 1883. The relative density of small mammals occurring in the nine Spanish sampling stations was twice that recorded in the Italian stations; however the number of species recorded in the different biotopes show similar mean values, ranging from three to five in Andalusia and from three to six in Calabria. Apodemus sylvaticus was the dominant species in the Calabrian stations, whereas Crocidura russula prevailed in Andalusia. The biotic diversity values are very similar in the Calabrian and Andalusian biotopes. By contrast, the Insectivora/Rodentia ratio was always higher in Andalusia. The more xerophytic biotopes showed greater similarities between the communities in Southern Spain and Southern Italy, while the cooler biotopes differed between these two peninsulas.
Keywords: habitat type; Italy; peninsular effect; sclerophyll biome; Small mammal communities; Spain

Co-occurrence of trees with different leaf habit: A functional approach on Mediterranean oaks - Damesin, Claire; Rambal, Serge; Joffre, Richard (Acta Oecologica, 1998)
Tree species can be split into two groups in terms of their leaf life-spans: evergreens and deciduous. Their distinct geographical dis- tribution suggests that these two groups have functional characteristics adapted to specific environments. However, deciduous and evergreen trees co-exist in some regions, such as those with a Mediterranean climate. They provide good models for comparing the properties of both trees and obtaining an understanding of how diversity is maintained. This is the case in southern France, where the evergreen holm oak (Quercus ilex) and the deciduous downy oak (Quercus pubescens) co-exist. A research programme has been conducted which compares the functioning of these two species at various scales, with the aim of anticipating their distribution in the event of climatic change. The ‘cost-benefit‘ model of Mooney and Dunn has been tested at leaf scale. Q. pubescens has a lower area-based construction cost than Q. ibex, but does not have a higher photosynthetic capacity. Despite differences in biochemical composition, size and mass per unit area, the leaves of the two species respond similarly to limited water conditions. Furthermore, the carbon isotope composition suggests that they have similar intrinsic water-use efficiencies. At the ecosystem scale, preliminary data are available on water, carbon and nitrogen use: i) measurements of leaf water potentials show that drought constraint starts at the same time and with the same rate and intensity in both species: ii) leaf area index was higher in Q. ilex woodlands; and iii) the release rate of nitrogen from the litter was faster in Q. ilex ecosystems. Together, these results indicate that the key factors distinguishing functions of deciduous and evergreen Quercus are more apparent at the ecosystem level than at the leaf level
Keywords: carbon isotope composition; construction cost; deciduous tree; evergreen tree; leaf area index; leaf gas exchange; Leaf habit; Mediterranean-type climate; nitrogen content; Quercus ilex; Quercus pubescens

Co-occurrence of trees with different leaf habit: A functional approach on Mediterranean oaks - Damesin, Claire; Rambal, Serge; Joffre, Richard (Acta Oecologica, 1998)
Tree species can be split into two groups in terms of their leaf life-spans: evergreens and deciduous. Their distinct geographical dis- tribution suggests that these two groups have functional characteristics adapted to specific environments. However, deciduous and evergreen trees co-exist in some regions, such as those with a Mediterranean climate. They provide good models for comparing the properties of both trees and obtaining an understanding of how diversity is maintained. This is the case in southern France, where the evergreen holm oak (Quercus ilex) and the deciduous downy oak (Quercus pubescens) co-exist. A research programme has been conducted which compares the functioning of these two species at various scales, with the aim of anticipating their distribution in the event of climatic change. The ‘cost-benefit‘ model of Mooney and Dunn has been tested at leaf scale. Q. pubescens has a lower area-based construction cost than Q. ibex, but does not have a higher photosynthetic capacity. Despite differences in biochemical composition, size and mass per unit area, the leaves of the two species respond similarly to limited water conditions. Furthermore, the carbon isotope composition suggests that they have similar intrinsic water-use efficiencies. At the ecosystem scale, preliminary data are available on water, carbon and nitrogen use: i) measurements of leaf water potentials show that drought constraint starts at the same time and with the same rate and intensity in both species: ii) leaf area index was higher in Q. ilex woodlands; and iii) the release rate of nitrogen from the litter was faster in Q. ilex ecosystems. Together, these results indicate that the key factors distinguishing functions of deciduous and evergreen Quercus are more apparent at the ecosystem level than at the leaf level
Keywords: carbon isotope composition; construction cost; deciduous tree; evergreen tree; leaf area index; leaf gas exchange; Leaf habit; Mediterranean-type climate; nitrogen content; Quercus ilex; Quercus pubescens

Cork hygroscopic equilibrium moisture content - Gil, L; Cortiço, P (European Journal of Wood and Wood Products, 1998)
This work is related to the establishment of the curves of cork moisture content in hygroscopic equilibrium (HEM curves), which allow to predict the moisture content of cork planks, one of the most important parameters in cork trading and processing. HEM curves for 20 ~ and 40 ~ based on an empirical model related to experimental data, were mathematically treated in order to set a series of curves in steps of 5 ~ These curves were transformed in a more usual display of the hygroscopic equilibrium mois- ture content, for the most common temperature and hu- midity ranges and tested against experimental data using two cork types.
Keywords: Cork; HEM curves (voyant); Moisture content; weight

Cork suberin as a new source of chemicals. 1. Isolation and chemical characterization of its composition. - Cordeiro, N.; Belgacem, M. N.; Silvestre, a J.; Pascoal Neto, C.; Gandini, A. (International journal of biological macromolecules, 1998)
Extractive-free cork from Quercus suber L. was submitted to a solvolysis treatment with methanolic NaOH which yielded 37% (o.d. cork) of suberin. This mixture of compounds was thoroughly characterized by FTIR, 1H- and 13C-NMR, gas chromatography coupled with mass spectrometric (GC-MS) analysis, vapour pressure osmometry (VPO), mass spectrography (MS) and gel permeation chromatography (GPC). After derivatization, the main components of the volatile fraction, representing less than half of the total, were found to be omega-hydroxymonocarboxylates, alpha, omega-dicarboxylates, simple alkanoates and 1-alkanols, all with chain lengths ranging from C16 to C24. A second fraction, with an average molecular weight about three times higher, was detected by VPO, MS and GPC. The presence of this important fraction in cork suberin had not been recognized in earlier studies. Both fractions constitute interesting precursors for the elaboration of new materials.
The following values have no corresponding Zotero field: accession-num: 9585884
Keywords: Alkaline methanolysis; Chemical characterization; Cork; Molecular weight distribution; Quercus suber L.; suberin

Cork suberin as a new source of chemicals. 1. Isolation and chemical characterization of its composition. - Cordeiro, N; Belgacem, M N; Silvestre, a J; Pascoal Neto, C; Gandini, A (International journal of biological macromolecules, 1998)
Extractive-free cork from Quercus suber L. was submitted to a solvolysis treatment with methanolic NaOH which yielded 37% (o.d. cork) of suberin. This mixture of compounds was thoroughly characterized by FTIR, 1H- and 13C-NMR, gas chromatography coupled with mass spectrometric (GC-MS) analysis, vapour pressure osmometry (VPO), mass spectrography (MS) and gel permeation chromatography (GPC). After derivatization, the main components of the volatile fraction, representing less than half of the total, were found to be omega-hydroxymonocarboxylates, alpha, omega-dicarboxylates, simple alkanoates and 1-alkanols, all with chain lengths ranging from C16 to C24. A second fraction, with an average molecular weight about three times higher, was detected by VPO, MS and GPC. The presence of this important fraction in cork suberin had not been recognized in earlier studies. Both fractions constitute interesting precursors for the elaboration of new materials.
Keywords: Alkaline methanolysis; Chemical characterization; Cork; Molecular weight distribution; Quercus suber L.; suberin

Cork suberin as a new source of chemicals: 2. Crystallinity, thermal and rheological properties - Cordeiro, N.; Belgacem, N. M.; Gandini, A.; Neto, C. P. (Bioresource technology, 1998)
Suberin samples, obtained by alkaline methanolysis from cork (Quercus suber L.), were submitted to various physical characterizations; DSC, TGA, optical microscopy, density and rheological properties. A sub- stantial proportion of these oligomers possessed a microcrystalline character with a melting range between 0 and 50°C. The amorphous part was liquid at room temperature and did not display a detectable glass transition upon cooling because of its wide molecular weight distribution. The viscous behaviour of suberin at room temperature was both plastic and thixotropic because of the structuring role of the micro- crystals
Keywords: Alkaline methanolysis; cork of Quercus suber L.; crystallinity; Density; rheological properties; suberin; thermal characterization

Cork suberin as a new source of chemicals: 2. Crystallinity, thermal and rheological properties - Cordeiro, N; Belgacem, N M; Gandini, A; Neto, C P (Bioresource technology, 1998)
Suberin samples, obtained by alkaline methanolysis from cork (Quercus suber L.), were submitted to various physical characterizations; DSC, TGA, optical microscopy, density and rheological properties. A sub- stantial proportion of these oligomers possessed a microcrystalline character with a melting range between 0 and 50°C. The amorphous part was liquid at room temperature and did not display a detectable glass transition upon cooling because of its wide molecular weight distribution. The viscous behaviour of suberin at room temperature was both plastic and thixotropic because of the structuring role of the micro- crystals
Keywords: Alkaline methanolysis; cork of Quercus suber L.; crystallinity; Density; rheological properties; suberin; thermal characterization

Cynegetical development of the French Mediterranean ``matorral'' scrublands: Case of wild ungulates - Maillard, D; Melac, O; Gaudin, J C; Vassant, J (GIBIER FANE SAUVAGE - GAME AND WILDLIFE, VOL 15 (SPECIAL NUMBER PTS 2 AND 3) 1998, 1998)
Since the beginning of the seventies, the marorrals (garrigues, maquis, and holly oak, Quercus ilex, copses) are slowly being colonized by roe deer, Capreolus capreolus, white wild boar; Sus scrofa, populations are stongly increasing. This phenomenon is mainly due to a relative low hunting pressure compared to the potential huntable population, to the disappearance of traditional farming practices (rural abandonment) causing the matorrals to extend, to the compensations paid to farmers since 1969, and to an increase in food resources (ageing of holly oak copses). As for red deer, Cervus elaphus, its population is increasing very slowly: The uncontrolled increase in wild boar populations is causing intolerable damages to farmers, especially in high-quality crops (arboriculture, vines, market-garden crops), which have been expanding since the productive lands in the bottom of the valley are being cultivated and agricultural techniques have improved. In the years to come, the ungulates frequenting the garrigue may become a harvestable resource if the two main sympatric species (wild boar and roe deer) which are occupying areas of some 30,000 ha, are wisely managed and the following parameters are taken into account : - amount of food produced in the habitats (annual mast crops); - damage control by controlled hunting in each massif, and damage prevention (protection or dissuation); - appropriate management of ungulate territories and the effective control of their populations based on hunting bag analyses in the middle and at the end of the hunting season. Most of ail it is important that before applying the ``population/environment/damage{''} model in each massif or management unit, clear management objectives be defined in agreement with the farmers.
IUGB XXIIIrd Congress, LYON, FRANCE, SEP 01-06, 1997
Keywords: roe deer; Sus scrofa; Wild boar; wild ungulate

Datos sobre la flora y vegetación de la Serranía de Ronda (Málaga, España) - Pérez Latorre, A V; Navas, P; Navas, D; Gil, Yolanda; Cabezudo, Baltasar (Acta Botanica Malacitana, 1998)
New data on flora and vegetation in the Serranía de Ronda (Málaga, Andalusia, Spain). A floristic and phytosociologial study has been done in the Natural Park Sierra de las Nieves, placed in Málaga (Andalusia, Spain). A total of 1.400 taxa have been recorded, fom which we have pointed out and commented 36, due to their biological value as endemisms, rare, protected or endemic species or new records in the studied area. One new taxonomical combination is proposed: Ulex baeticus subsp. bourgaeanus. A total of 78 associations and communities have been recorded. New sintaxa are described: one alliance (Pino pinastri-Juniperion phoeniceae), 12 associations, 9 subassociations and one new combination. The 6 climactic series described with their main tree species, soil and bioclimatic range are the following: two series of Quercus suber (termo-mesomediterranean on schists), one of Quercus rotundifolia (mesomediterranean on limestones), one of Quercus pyrenaica (mcsomediterranean on schists), one of Quercus alpestris (supramediterranean on limestones) and one of Juniperus sabina (oromediterranean on limestones). The 5 edaphoxeric series described with their main tree species, soil and bioclimatic range are the following: two series of Abies pinsapo (meso-supramediterranean on perdotite rocks and dolomite), two series of Juniperus phoenicea (termo-meso-supramediterranean on marble, dolomite and limestones) and one of Pious pinaster (termo-mesomediterranean on peridotite rocks). The 5 riverine edaphoseries described with their main tree species, soil and water-level range are the following: one of Fraxinus angustifolia (summer-droughted rivers on limestones), two of Salix pedicellata (summer-droughted rivers on peridotite rocks, schists and limestones) and two of Nerium oleander (seasonal streams, on peridotite rocks, schists and limestones). Finally, the complete sintaxonomic scheme, with new sintaxa, combinations, hierarchycity and comments on the associations and communities is given
Keywords: Andalusia; Flora; Málaga; series; Serranía de Ronda; Spain; Vegetation

Decomposition of the organic matter in two forest ecosystems (Natural Park of Montseny, Spain) - I. Abundance, biomass and distribution of the soil microarthropods - Andres, P; Athias-Binche, F (VIE ET MILIEU-LIFE AND ENVIRONMENT, 1998)
This paper represents the first part of a larger work concerning the importance of the oribatid mites in the edaphic trophic chains of two forests (holm-oak and beech woods) under Mediterranean conditions. We offer here the data relating to annual changes of abundance, biomass and vertical distribution of the mesofauna sorted according taxonomic and trophic criteria. The soil was divided into three layers : fresh fallen leaves (L), fermentation layer (F) and organic horizon (S). Rate of leaf imput, dynamics of decomposition, environmental trophic supply, physical structure of the soil and seasonal drought constitute the factors determining the richness and the spatial arrangement of the fauna.
Keywords: decomposition; green oak woodlands; microarthropods; Soil

Decomposition of the organic matter in two forest ecosystems (Natural Park of Montseny, Spain) - I. Abundance, biomass and distribution of the soil microarthropods - Andres, P.; Athias-Binche, F. (VIE ET MILIEU-LIFE AND ENVIRONMENT, 1998)
This paper represents the first part of a larger work concerning the importance of the oribatid mites in the edaphic trophic chains of two forests (holm-oak and beech woods) under Mediterranean conditions. We offer here the data relating to annual changes of abundance, biomass and vertical distribution of the mesofauna sorted according taxonomic and trophic criteria. The soil was divided into three layers : fresh fallen leaves (L), fermentation layer (F) and organic horizon (S). Rate of leaf imput, dynamics of decomposition, environmental trophic supply, physical structure of the soil and seasonal drought constitute the factors determining the richness and the spatial arrangement of the fauna.
The following values have no corresponding Zotero field: pub-location: LABORATOIRE ARAGO, BP 44, 66651 BANYULS-SUR-MER CEDEX, FRANCE publisher: OBSERVATOIRE OCEANOLOGIQUE BANYULS
Keywords: decomposition; green oak woodlands; microarthropods; Soil

Deriving indicators of soil degradation from soil aggregation studies in southeastern Spain and southern France - Cammeraat, L H; Imeson, A C (Geomorphology, 1998)
Soil degradation is perceived as a major threat in the Mediterranean region due to changes in land-use and possible future climate change. Soil aggregation parameters are used here to demonstrate their potential as a key-indicator for land degradation studies. The monitoring of these indicators offers a means of establishing the vulnerability and resilience of geo-ecosystems. Soil aggregation stability and distribution were studied on soils with an open shrubby vegetation cover, from several places in southeastern Spain and southern France, by applying drop tests and determining aggregate size distributions. Aspect and vegetation cover were incorporated in the soil sampling. Several indices were derived from these analyses to indicate the degree of soil aggregation. This was done by referencing to a base level of aggregation bare soil aggregation . It was found that soil aggregates were more stable and were often coarser under vegetation, when compared to . their immediate surrounding bare areas. A similar, slightly less clear effect was noted on N-facing exposed slopes when compared to S-facing exposed slopes. Long-term changes were found by studying cultivated land, abandoned fields and land covered by semi-natural vegetation, on comparable substrate and comparable land units. It is clear that soil aggregation and aggregate stability increases with time years . It is argued that soil aggregation indices can be used as a key-indicator for . degradation processes at a fine scale with implications for runoff and sediment generating processes at the hillslope scale
Keywords: degradation; Soil; Vegetation

Deriving indicators of soil degradation from soil aggregation studies in southeastern Spain and southern France - Cammeraat, L. H.; Imeson, A. C. (Geomorphology, 1998)
Soil degradation is perceived as a major threat in the Mediterranean region due to changes in land-use and possible future climate change. Soil aggregation parameters are used here to demonstrate their potential as a key-indicator for land degradation studies. The monitoring of these indicators offers a means of establishing the vulnerability and resilience of geo-ecosystems. Soil aggregation stability and distribution were studied on soils with an open shrubby vegetation cover, from several places in southeastern Spain and southern France, by applying drop tests and determining aggregate size distributions. Aspect and vegetation cover were incorporated in the soil sampling. Several indices were derived from these analyses to indicate the degree of soil aggregation. This was done by referencing to a base level of aggregation bare soil aggregation . It was found that soil aggregates were more stable and were often coarser under vegetation, when compared to . their immediate surrounding bare areas. A similar, slightly less clear effect was noted on N-facing exposed slopes when compared to S-facing exposed slopes. Long-term changes were found by studying cultivated land, abandoned fields and land covered by semi-natural vegetation, on comparable substrate and comparable land units. It is clear that soil aggregation and aggregate stability increases with time years . It is argued that soil aggregation indices can be used as a key-indicator for . degradation processes at a fine scale with implications for runoff and sediment generating processes at the hillslope scale
Keywords: degradation; Soil; Vegetation

Detection of Cork Taint in Wine Using Automated Solid-Phase MicroExtraction in Combination with GC/MS-SIM - Butzke, Christian; Evans, Thomas; Ebeler, Susan (Chemistry of Wine Flavor, 1998)
Cork taint is a musty/moldy off-odor in wine. It is related to the cork stopper, a wine bottle closure made from the bark of the cork oak (Quercus suber). In a correlation between sensory evaluation and chemical analysis, 2,4,6-trichloroanisole (TCA) has been identified as a major impact component. In sensitivity tests of a group of trained wine judges, a geometric mean of the minimum detectable concentrations of TCA has been determined at 4.6 ng/L. Solid Phase MicroExtraction (SPME) is a solvent-free sample preparation method based on the adsorption of analytes directiy from an aqueous sample onto a coated fused-silica fiber. Headspace SPME was used in combination with gas chromatography-mass spectrometry/ selective ion monitoring (GC/MS-SIM) to analyze for TCA in wine. Wines were spiked with TCA, and its deuterated stable isotope, 2H5-TCA, was used as an internal standard. The extraction fiber of the SPME, coated with polymethylsiloxane, was exposed for 25 minutes in the headspace of the sample vial, and then injected into the injection port of the GC-MS by a Varian 8200 CX autosampler. Limit of quantification of this method was 5 ng/L. The method was linear from 5 to 250 ng/L with an overall coefficient of variation for replicate analyses of less than 13%.
doi:10.1021/bk-1998-0714.ch015
Keywords: Cork stoppers; Cork taint; SPME/GC-MS (voyant); TCA

Detection of Cork Taint in Wine Using Automated Solid-Phase MicroExtraction in Combination with GC/MS-SIM - Butzke, Christian; Evans, Thomas; Ebeler, Susan (Chemistry of Wine Flavor, 1998)
Cork taint is a musty/moldy off-odor in wine. It is related to the cork stopper, a wine bottle closure made from the bark of the cork oak (Quercus suber). In a correlation between sensory evaluation and chemical analysis, 2,4,6-trichloroanisole (TCA) has been identified as a major impact component. In sensitivity tests of a group of trained wine judges, a geometric mean of the minimum detectable concentrations of TCA has been determined at 4.6 ng/L. Solid Phase MicroExtraction (SPME) is a solvent-free sample preparation method based on the adsorption of analytes directiy from an aqueous sample onto a coated fused-silica fiber. Headspace SPME was used in combination with gas chromatography-mass spectrometry/ selective ion monitoring (GC/MS-SIM) to analyze for TCA in wine. Wines were spiked with TCA, and its deuterated stable isotope, 2H5-TCA, was used as an internal standard. The extraction fiber of the SPME, coated with polymethylsiloxane, was exposed for 25 minutes in the headspace of the sample vial, and then injected into the injection port of the GC-MS by a Varian 8200 CX autosampler. Limit of quantification of this method was 5 ng/L. The method was linear from 5 to 250 ng/L with an overall coefficient of variation for replicate analyses of less than 13%.
doi:10.1021/bk-1998-0714.ch015doi:10.1021/bk-1998-0714.ch015The following values have no corresponding Zotero field: periodical: Chemistry of Wine Flavor electronic-resource-num: doi:10.1021/bk-1998-0714.ch015
Keywords: Cork stoppers; Cork taint; SPME/GC-MS (voyant); TCA

Diet selection by sheep and goats on Mediterranean heath-woodland range - Bartolomé, J.; Franch, J.; Plaixats, J.; Seligman, N. G. (JOURNAL OF RANGE MANAGEMENT, 1998)
The study determined the species components of the diets of small ruminants grazing mountain ranges of the Montseny Biosphere Reserve (Catalunya, NE Spain). Three mixed flocks of sheep and goats, led by shepherds, were monitored for a year. Animals grazed a mountain rangeland composed of Qeurcus ilex woodland and Calluna-Erica heathland during the day and were returned to their corrals every night. Diet selection was estimated using fecal analysis. Of the 111 species that were identified, 71 were common to both sheep and goat. Of these, 23 were represented in proportions of more than 1% of the annual diet. Even though goats and sheep grazed together, their diets were significantly different (p < 0.0001), the animal factor accounting for 18% to 60% of the total variation among the main diet components. Variation between seasons was also a major (5% to 56%) highly significant factor, while differences between flocks accounted for a significant, but relatively small part (3% to 10%) of the total variation in diet. The outstanding difference was the avoidance of the tree, Quercus ilex, by the sheep while the goats selected it throughout the year. Sheep selected graminoids throughout the year while goats tended to avoid them. For the rest there.was substantial overlap in species composition between the diet of sheep and goats, especially when analysed over an entire cycle.
The following values have no corresponding Zotero field: pub-location: 445 UNION BLVD, STE 230, LAKEWOOD, CO 80228-1259 USA publisher: SOC RANGE MANAGEMENT
Keywords: calluna vulgaris; Erica arborea; fecal analysis; microhistological analysis; Quercus ilex

Diet selection by sheep and goats on Mediterranean heath-woodland range - Bartolomé, J; Franch, J; Plaixats, J; Seligman, N G (JOURNAL OF RANGE MANAGEMENT, 1998)
The study determined the species components of the diets of small ruminants grazing mountain ranges of the Montseny Biosphere Reserve (Catalunya, NE Spain). Three mixed flocks of sheep and goats, led by shepherds, were monitored for a year. Animals grazed a mountain rangeland composed of Qeurcus ilex woodland and Calluna-Erica heathland during the day and were returned to their corrals every night. Diet selection was estimated using fecal analysis. Of the 111 species that were identified, 71 were common to both sheep and goat. Of these, 23 were represented in proportions of more than 1% of the annual diet. Even though goats and sheep grazed together, their diets were significantly different (p < 0.0001), the animal factor accounting for 18% to 60% of the total variation among the main diet components. Variation between seasons was also a major (5% to 56%) highly significant factor, while differences between flocks accounted for a significant, but relatively small part (3% to 10%) of the total variation in diet. The outstanding difference was the avoidance of the tree, Quercus ilex, by the sheep while the goats selected it throughout the year. Sheep selected graminoids throughout the year while goats tended to avoid them. For the rest there.was substantial overlap in species composition between the diet of sheep and goats, especially when analysed over an entire cycle.
Keywords: calluna vulgaris; Erica arborea; fecal analysis; microhistological analysis; Quercus ilex

Differences in the response of carbon assimilation to summer stress (water deficits, high light and temperature) in four Mediterranean tree species - Faria, T; Silvério, D; Breia, E; Cabral, R; Abadía, A; Abadia, J; Pereira, J S; Chaves, M M (Physiologia Plantarum, 1998)
Daily changes in photoprotective mechanisms were studied in sun leaves of Quercus suber L., Quercus ilex L., Olea europaea L. and Eucalyptus globulus Labill. trees during the summer in Portugal. Even though stomatal closure explained most of the diurnal variation in carbon assimilation along the summer, a decline in the photochemical yield of photosystem II (F′v/F′m) also occurred, as a result of an excess of intercepted solar radiation when carbon assimilation is limited by stomatal closure due to high vapour pressure deficits and/or soil water deficits. These changes were accompanied by the conversion of violaxanthin to antheraxanthin and zeaxanthin which were correlated with thermal dissipation of excess photon energy. In spite of a common general response, differences between species were observed -Olea europaea, which is a slow-growing tree, had the lowest net photosynthetic rates, the highest proportion of carotenoids in relation to chlorophyll and the highest rates of de-epoxidation of violaxanthin. This enabled a large thermal dissipation of the excess intercepted radiation but led to rather small values of light utilisation for photochemistry (ca 20%). In contrast, in E. globulus, a fast-growing tree, photosynthetic rates were the highest, thermal dissipation of absorbed radiation the lowest and maximal values of light utilisation for photochemistry reached ca 50%. The two Quercus species exhibited an intermediate response. A high degree of co-ordination is apparent between stomatal behaviour, photosynthetic capacity and photoprotection mechanisms.
Keywords: Energy dissipation; Eucalyptus globulus; Olea europaea; photosynthesis; Quercus ilex; Quercus suber; xanthophyll cycle; zeaxanthin

The dispersal of a dry-fruited shrub by red deer in a Mediterranean ecosystem - Malo, Juan E; Suárez, Francisco (Ecography, 1998)
Seed dispersal of dry-fruited shrubs has received little attention in Mediterranean areas despite their frequency in the vegetation and the consideration given to the dispersal of fleshy-fruited shrubs in the area. Red deer faeces has recently been found to contain large numbers of seeds from one of the most common shrubs of this group, gum cistus Cistus ladanifer, although its importance in the reproduction of the species is unknown. This study examines the role of the red deer as an effective disperser of C. ladanifer. For this purpose, we quantify i) the C. ladanifer seed content in red deer dung over a year, ii) the seed shadow generated by the red deer wish their faeces during the same period, and iii) the ability of the dung-borne seeds to germinate and establish as seedlings under field conditions within five years following excretion. The results reveal an extremely high seed Content of the species in red deer dung (up to 80.5 ± 41.9 germinable seeds g-1), which is virtually confined to the summer (July–August), when we estimate that a red deer defecates up to 24 000 seeds of the species per day. Furthermore, red deer mainly deposit gum cistus seeds amongst plant formations lacking the species: over the year, red deer excrete <2600 seeds m-2 in C. ladanifer-dominated scrub and 7400–8800 seeds m-2 in other plant formations. Under natural conditions, the dung-borne seeds have a more sniggered among-years germination pattern than free seeds in the soil. Though no seedling survived its first summer drought, the survival of seedlings sprouted from dung was significantly longer than that of control seedlings in the first and third years after deposition, and indistinguishable from it the second, fourth and fifth years. This is the first quantification of the importance of red deer to C. ladanifer dispersal and establishment, and suggests that endozoochory by mammalian herbivores can be very valuable for dry-fruited shrubs in the Mediterranean region.
Keywords: endozoochory; red deer; seed dispersal; seedling establishment (PG)

The dispersal of a dry-fruited shrub by red deer in a Mediterranean ecosystem - Malo, Juan E.; Suárez, Francisco (Ecography, 1998)
Seed dispersal of dry-fruited shrubs has received little attention in Mediterranean areas despite their frequency in the vegetation and the consideration given to the dispersal of fleshy-fruited shrubs in the area. Red deer faeces has recently been found to contain large numbers of seeds from one of the most common shrubs of this group, gum cistus Cistus ladanifer, although its importance in the reproduction of the species is unknown. This study examines the role of the red deer as an effective disperser of C. ladanifer. For this purpose, we quantify i) the C. ladanifer seed content in red deer dung over a year, ii) the seed shadow generated by the red deer wish their faeces during the same period, and iii) the ability of the dung-borne seeds to germinate and establish as seedlings under field conditions within five years following excretion. The results reveal an extremely high seed Content of the species in red deer dung (up to 80.5 ± 41.9 germinable seeds g-1), which is virtually confined to the summer (July–August), when we estimate that a red deer defecates up to 24 000 seeds of the species per day. Furthermore, red deer mainly deposit gum cistus seeds amongst plant formations lacking the species: over the year, red deer excrete <2600 seeds m-2 in C. ladanifer-dominated scrub and 7400–8800 seeds m-2 in other plant formations. Under natural conditions, the dung-borne seeds have a more sniggered among-years germination pattern than free seeds in the soil. Though no seedling survived its first summer drought, the survival of seedlings sprouted from dung was significantly longer than that of control seedlings in the first and third years after deposition, and indistinguishable from it the second, fourth and fifth years. This is the first quantification of the importance of red deer to C. ladanifer dispersal and establishment, and suggests that endozoochory by mammalian herbivores can be very valuable for dry-fruited shrubs in the Mediterranean region.
The following values have no corresponding Zotero field: publisher: Blackwell Publishing Ltd
Keywords: endozoochory; red deer; seed dispersal; seedling establishment (PG)

Distribución de los macrolíquenes corticícolas y su relación con la vegetación en el Parque Natural de los Alcornocales (Cádiz, S de España) - HERNÁNDEZ GALLEGO, Y; DÍAZ ESPEJO, A; ROWE, J G (Acta botánica malacitana, 1998)
Bark macrolichens were studied in different vegetation communities: evergreen cork oak (Quercus suber L.) woodlands, semideciduous oak (Quercus canariensis Willd.) woodlands and wild olive trees (O/ea europaea L. var. oleaster DC.); the influence of lichen orientation on the composition and species number, as well as the effect of the phorophyte perimeter on the bark macrolichens diversity were studied. Semideciduous oak woodlands were found clearly different from the other groups of samples. Differences between north and south orientation in the group of plots of wild olive trees were detected. It was also observed that in the wild olive trees, the macrolichen diversity decreased when the phorophyte perimeter increased.
Keywords: bark macrolichens; distribution; Los Alcornocales Natural Park

Ecological food production from animal origin in the dehesa agrosystem of Andalucia and Extremadura - Mata, C.; Caballero, I.; Labrador, J.; Casco, J. M. G. (BASIS OF THE QUALITY OF TYPICAL MEDITERRANEAN ANIMAL PRODUCTS, 1998)
Andalucia and Extremadura gather certain advantages and conditions for the development of ecological stockbreeding which place them among the European territories of greatest potential in this sense. There are wide areas of high environmental balance, some of them declared as Natural Protected Areas-, with soils of only forestal and silvopastoral use, and with a lot of farms used for the traditional extensive stockbreeding. In this area the management is close to the ecological stockbreeding, and the location coincides with the one of dehesa farms. Most of these farms suffer problems derived from the pressure to which they are subjected because of a management towards greater intensification. Their functions are not valued properly. Many times their products are not competitive with the usual market prices. Being, however of greater organoleptic, sanitary, environmental quality and being even greater, their possibility of profitability. The conversion of extensive stockbreeding farms into a type of ecological production may provide solutions to these problems, favouring a consolidated development; and at the same time, it may encourage an action integrated with other agrarian farms, producing sites of pluriactivity and much more profitability. This work shows a description of the most relevant aspects of extensive stockbreeding productions in relation to its conversion into the ecological production.
The following values have no corresponding Zotero field: periodical: BASIS OF THE QUALITY OF TYPICAL MEDITERRANEAN ANIMAL PRODUCTS issue: 90 pub-location: POSTBUS 220, 6700 AE WAGENINGEN, NETHERLANDS
Keywords: animal ecological production; Dehesa

Ecological food production from animal origin in the dehesa agrosystem of Andalucia and Extremadura - Mata, C; Caballero, I; Labrador, J; Casco, J M G (BASIS OF THE QUALITY OF TYPICAL MEDITERRANEAN ANIMAL PRODUCTS, 1998)
Andalucia and Extremadura gather certain advantages and conditions for the development of ecological stockbreeding which place them among the European territories of greatest potential in this sense. There are wide areas of high environmental balance, some of them declared as Natural Protected Areas-, with soils of only forestal and silvopastoral use, and with a lot of farms used for the traditional extensive stockbreeding. In this area the management is close to the ecological stockbreeding, and the location coincides with the one of dehesa farms. Most of these farms suffer problems derived from the pressure to which they are subjected because of a management towards greater intensification. Their functions are not valued properly. Many times their products are not competitive with the usual market prices. Being, however of greater organoleptic, sanitary, environmental quality and being even greater, their possibility of profitability. The conversion of extensive stockbreeding farms into a type of ecological production may provide solutions to these problems, favouring a consolidated development; and at the same time, it may encourage an action integrated with other agrarian farms, producing sites of pluriactivity and much more profitability. This work shows a description of the most relevant aspects of extensive stockbreeding productions in relation to its conversion into the ecological production.
Keywords: animal ecological production; Dehesa

Ecology and history of a wooded landscape in southern Spain - MARAÑÓN, T; Ojeda, J F (ECOLOGICAL HISTORY OF EUROPEAN FORESTS, 1998)
An extensive oak woodland, of about 1000 km(2), dominated by evergreen cork oak (Quercus suber) and semideciduous Q. canariensis, is found in southern Spain, near the Strait of Gibraltar, and contrasts with the paradigm of deforested Mediterranean mountains. Several factors, ecological, geographical and historical, have contributed to the origin and maintenance of this forested landscape. The rough relief and the acidic, nutrient-poor soils (derived from Oligo-Miocene sandstone) made this area unsuitable for cultivation. The oceanic influence favours the growth of oak trees. In particular, the cork oak is well suited to acidic soils and the humid Mediterranean climate. Three historical milestones seem relevant to the preservation of this woodland. Its location at a frontier during medieval times (thirteenth to fifteenth centuries) discouraged villages and reduced human pressure on the woodland resources. The rise of the value of cork helped to preserve the cork oak woodland during early nineteenth. century industrial times. contemporary consciousness about the conservation of woodland landscapes (somewhat unusual in the Mediterranean region) led to their designation as Los Alcornocales (meaning `The cork oak woodlands') Natural Park, devoted to the eco-development of the region.
Keywords: Cork oak; forest landscape; human pressure; Mediterranean climate; Oak woodlands; Quercus canariensis; Quercus suber

The effect of drought on gas exchange and water potential in leaves of seven Mediterranean woody species - Gucci, R; Massai, R; Casano, S; Gravano, E; Lucchesini, M (IMPACTS OF GLOBAL CHANGE ON TREE PHYSIOLOGY AND FOREST ECOSYSTEMS, 1998)
The water relations and gas exchange parameters of Arbutus unedo, Cistus monspeliensis, Erica arborea, Myrtus communis, Phillyrea latifolia, Pistacia lentiscus, and Quercus ilex growing in the shrubland vegetation at the Parco Naturale della Maremma (Italy), were studied over two consecutive years. At high leaf water potentials, photosynthetic rates and stomatal conductance were relatively low in all species but C. monspeliensis. Stomatal conductance remained relatively high in C. monspeliensis leaves as soil moisture was depleted, whereas A. unedo, E. arborea, M. communis, and P. lentiscus were more conservative in water use. P. latifolia and Q. ilex showed a drought-tolerant behaviour.
Keywords: Drought tolerance; leaf water potential; Phenology; Stomatal conductance

Effects of elevated CO2 and decreased water availability on holm-oak seedlings in controlled environment chambers - López, B; Sabate, S; Ruiz, I; Gracia, C (IMPACTS OF GLOBAL CHANGE ON TREE PHYSIOLOGY AND FOREST ECOSYSTEMS, 1998)
In Mediterranean ecosystems, water is an important limiting factor for plant growth. In addition to the increase in atmospheric CO2, some models predict increased drought in Mediterranean areas as a consequence of global change. Thus, to determine how increased atmospheric CO2 interacts with increased water stress and affects Mediterranean plant growth is an important achievement. The present study analyses how helm oak (Quercus ilex L.) seedlings are affected by both elevated CO2 and increased water stress. The CO2 concentrations were supplied in controlled environment chambers (350 and 500 ppm CO2), and water stress was performed according to a Mediterranean pattern (Potential Evapotranspiration to Rainfall ratio). The increased water stress was attained by watering half of the Mediterranean reference pattern. Results show that the positive effects of elevated CO2 on photosynthesis and growth are counteracted by increased water stress.
Keywords: CO2; controlled environment chambers; Quercus ilex

Effects of long-term elevated CO2 on foliage characteristics of Quercus ilex L. and Juniperus communis L. - Verkaik, E; Bartelink, H H (IMPACTS OF GLOBAL CHANGE ON TREE PHYSIOLOGY AND FOREST ECOSYSTEMS, 1998)
To study the effects of long-term elevated CO2 on Quercus ilex and Juniperus communis, leaves from plants growing close to a natural CO2 spring and from plants at a control site were collected and analyzed. Starch concentrations in leaves were found to be higher for plants growing under high CO2. Nitrogen concentrations were lower, but only in Juniperus communis. No differences in stomatal densities were found. The results indicate that in a CO2 -elevated environment, growth of both species will be different: Quercus ilex will be able to take advantage of the higher CO2 levels in spring, whereas in both species limited sink availability in the middle of the growing season will result in increased starch concentrations.
Keywords: CO2-springs; nitrogen; starch; stomatal density

Environmental impact of neolithic and bronze age farming in the eastern Pyrenees forelands, based on multidisciplinary investigations at La Caune de Blesta (Blesta Cave), near Perpignan, France - Brochier, Jacques E; Claustre, Franoise; Heinz, Christine (Vegetation History and Archaeobotany, 1998)
Results of multidisciplinary studies, involving anthracology, archaeology and geoarchaeology, that have been carried out on Neolithic to Brenze Age depos- its from B61esta Cave, eastern Pyrenees, are reported. These show that the type of human activity, i.e. pastoral- ism alone or a more diversified farming economy, and continuity/discontinuity of occupation are the main fac- tors that determine the structure and evolution of the Holocene vegetation in the region. Neolithic pastoral ac- tivities were not continuous and so did not have an en- during influence on the natural environment. The more continuous and diversified exploitation associated with Bronze Age cultures was responsible for the develop- ment and maintenance of the low garrigues.
Keywords: Agro-pastoral system; Bronze Age; Eastern Pyrenees; Neolithic; Vegetation dynamic

Environmental impact of neolithic and bronze age farming in the eastern Pyrenees forelands, based on multidisciplinary investigations at La Caune de Blesta (Blesta Cave), near Perpignan, France - Brochier, Jacques E.; Claustre, Franoise; Heinz, Christine (Vegetation History and Archaeobotany, 1998)
Results of multidisciplinary studies, involving anthracology, archaeology and geoarchaeology, that have been carried out on Neolithic to Brenze Age depos- its from B61esta Cave, eastern Pyrenees, are reported. These show that the type of human activity, i.e. pastoral- ism alone or a more diversified farming economy, and continuity/discontinuity of occupation are the main fac- tors that determine the structure and evolution of the Holocene vegetation in the region. Neolithic pastoral ac- tivities were not continuous and so did not have an en- during influence on the natural environment. The more continuous and diversified exploitation associated with Bronze Age cultures was responsible for the develop- ment and maintenance of the low garrigues.
Keywords: Agro-pastoral system; Bronze Age; Eastern Pyrenees; Neolithic; Vegetation dynamic

The EU Habitats Directive in Spain: can it contribute effectively to the conservation of extensive agroâ€ecosystems? - Beaufoy, G (Journal of Applied Ecology, 1998)
1. By adopting the Habitats Directive (Directive 92/43 of 21 May 1992 on the con- servation of natural habitats and of wild fauna and flora) in 1992, the governments of the European Community committed themselves to the creation of the Natura 2000 ecological network, with the aim of conserving an extensive range of European habitat types and wildlife species. In doing so, they set in motion the most significant initiative for nature conservation in the history of Europe. 2. In Spain, Natura 2000 will have a considerable impact on the conservation of habitats and species, potentially increasing the percentage of national territory within protected areas from 6% to as much as 20%. 3. This paper aims to illustrate the importance of extensive farming systems to the maintenance of habitats within Natura 2000, and vice versa.
Keywords: Biodiversity; European policy; Extensive farming; policy instruments.

The EU Habitats Directive in Spain: can it contribute effectively to the conservation of extensive agroâ€ecosystems? - Beaufoy, G. (Journal of Applied Ecology, 1998)
1. By adopting the Habitats Directive (Directive 92/43 of 21 May 1992 on the con- servation of natural habitats and of wild fauna and flora) in 1992, the governments of the European Community committed themselves to the creation of the Natura 2000 ecological network, with the aim of conserving an extensive range of European habitat types and wildlife species. In doing so, they set in motion the most significant initiative for nature conservation in the history of Europe. 2. In Spain, Natura 2000 will have a considerable impact on the conservation of habitats and species, potentially increasing the percentage of national territory within protected areas from 6% to as much as 20%. 3. This paper aims to illustrate the importance of extensive farming systems to the maintenance of habitats within Natura 2000, and vice versa.
Keywords: Biodiversity; European policy; Extensive farming; policy instruments.

Evaluation of goat milk and cheese qualities and the influence of the livestock production system in the Mediterranean - Goby, J P; Rochon, J J (BASIS OF THE QUALITY OF TYPICAL MEDITERRANEAN ANIMAL PRODUCTS, 1998)
The herds of dairy goats using marginal areas of the French Mediterranean region have a double objective: milk production and maintenance of the natural environment in areas prone to fires. The association of rearing techniques adapted to the conservation of the natural environment and to quality milk production is a key factor in the survival of the systems. In the Eastern Pyrenees, milk quality in two goat systems is studied. A rangeland-based system: situated at the piedemont of the Alberes Massif, the site integrates a cork oak grove with a maquis-type cover of Erica arborea. The herd grazes in the maquis and also feed on hay and concentrate. A system based on forage: situated on the plains, the herd is fed in the stable. The first results of the rangeland system show a large evolution of the butyric acid levels and and inversion of these levels in the summer. Judging from the selection made by the goats, the supply of nutrients on the rangeland is less rich in fibre than the composition of shrubs would lead us to think.
Keywords: cheese; Goat; Mediterranean area; milk; Quality

Exchange of atmospheric formic and acetic acids with trees and crop plants under controlled chamber and purified air conditions - Kesselmeier, J; Bode, K; Gerlach, C; Jork, E.-M (Atmospheric Environment, 1998)
We investigated the exchange of formic and acetic acids between the atmosphere and various tree species such as beech (Fagus sylvatica L.), ash (Fraxinus excelsior L.), spruce (Picea abies L.) Karst, holm oak (Quercus ilex L.), and birch (Betula pendula L.). and some crop-plant species such as corn (Zea mays, var. Banjo), pea (Pisum sativum, var. Solara), barley (Hordeum vulgare, var. Igri) and oat (Avena sativa, var. Wiesel). All experiments were done with dynamic enclosures ßushed with puriÞed oxidant-free air, containing only low or controlled amounts of the two acids. SigniÞcant and light-triggered emission of both acids from all tree species was observed. For one tree species (ash) a seasonal large increase in fall due to early leaf decomposition was found. The standard emission factors (30¡C and PAR"1000 kmol m2 s~1) given as (nmol m~2 min~1) for acetic and formic acids, respectively, were 8.1 and 29.7 (ash, autumn), 1.0 and 3.3 (ash, summer), 0.9 and 1.4 (beech), 0.7 and 1.45 (spruce), 1.9 and 2.4 (Holm oak) and 1.7 and 6.7 (birch). Rough estimation of global annual emissions range between 20 and 130 Gmol formic acid and 10 and 33 Gmol acetic acid. These numbers reßect a 15Ð30% contribution by forest emissions to the continental organic acid budget. As compared to the global total NMHC emissions low molecular weight organic acids are of minor importance. In contrast to the trees, none of the crop-plant species investigated showed an emission, but always a clear deposition of both acids. Both emission from trees as well as uptake by the agricultural plants could be related to transpiration rates and leaf conductances
Keywords: acetic acid; assimilation; Atmosphere; crop plants; exchange of volatile organic compounds; formic acid; leaf conductance; organic acids; Plants; Transpiration; Trees

Experimental research in ageing holm oak (Quercus ilex L.) coppices: preliminary results - la Marca, Orazio; Marziliano A., Pasquale; Moretti, Nicola (Ann. For. Sci., 1998)
The initial data of a long-term research programme aimed at determining the silvicultural choices for management of ageing holm oak coppices are reported. The various treatments being tested are the following: treatments A and B, respectively, with 50 and 250 reserve trees per hectare, all of the same age; treatment C with 140 reserve trees per hectare, with three different ages; treatment D, conversion into high forest; and treatment E, natural evolution (the control). A total of 15 permanent plots were established (five treatments x three replicates) and the experimental design used is that of randomized blocks. The results presented regard the structural development of the coppice during the first 2 years after coppicing. Regeneration from seed showed a significant correlation with treatment. Data relative to the characteristics of the stands existing before the various interventions also are given. Such preliminary results need further periodical observations
Keywords: coppice; cutting method; Quercus ilex L.; Regeneration; snow breakage

Experimental research in ageing holm oak (Quercus ilex L.) coppices: preliminary results - la Marca, Orazio; Marziliano A., Pasquale; Moretti, Nicola (Ann. For. Sci., 1998)
The initial data of a long-term research programme aimed at determining the silvicultural choices for management of ageing holm oak coppices are reported. The various treatments being tested are the following: treatments A and B, respectively, with 50 and 250 reserve trees per hectare, all of the same age; treatment C with 140 reserve trees per hectare, with three different ages; treatment D, conversion into high forest; and treatment E, natural evolution (the control). A total of 15 permanent plots were established (five treatments x three replicates) and the experimental design used is that of randomized blocks. The results presented regard the structural development of the coppice during the first 2 years after coppicing. Regeneration from seed showed a significant correlation with treatment. Data relative to the characteristics of the stands existing before the various interventions also are given. Such preliminary results need further periodical observations
Keywords: coppice; cutting method; Quercus ilex L.; Regeneration; snow breakage

Factors affecting movements and home ranges in the jay (Garrulus glandarius) - Rolando, Antonio (Journal of Zoology, 1998)
The winter home ranges, movements and density of the jay Garrulus glandarius in the Maremma Natural Park (Tuscany, Italy) are presented, and compared with those already known for the other seasons. The movements of jays were studied for short periods over 6 years by radiotelemetric techniques (26 home ranges), direct observations of movements from vantage points, and transect counts. Summer and autumn ranges were much larger than spring and winter ones. Incremental area plots and auto-overlap analyses showed that, on average, spring ranges increased in area with time without shifting, whereas winter ranges were rather stable. In both periods, however, some birds moved as floaters since the degree of range auto-overlap decreased significantly with time. In winter and spring, range sizes of jays inhabiting different habitats were significantly different, being larger in sites with higher habitat heterogeneity. The structure of home ranges was variable in all seasons; birds showed jointed and disjointed ranges, with one or more activity centres, in all the possible combinations. In every season the average degree of range overlap between jays caught at the same site was rather high and overall actual overlap, when non-tagged birds were also considered, was even higher. No territorial behaviour was ever observed. During summer jays moved into the pinewood for the greater part of the day to collect cicadas, Cicada orni, and returned to the maquis in the evening. During autumn birds regularly moved within the maquis or from the maquis to the pinewood to cache oak (Quercus ilex) acorns. No regular long movements between habitats were observed during spring and winter. Direct observations and analyses of pellets suggested that food was abundant and highly diversified throughout the year. Thus, seasonal movements and home ranges were flexible and mainly controlled by food availability and its distribution in space and time.
Keywords: home range; jay; movements; radiotelemetry; Seasonality

Feeding preferences of the collembolan Onychiurus sinensis for fungi colonizing holm oak litter ( Quercus rotundifolia Lam.) - Sadaka-Laulan, N; Ponge, J F (European Journal of Soil Biology, 1998)
Ten fungi isolated from decaying holm oak leaves (Quercus rotundifolia Lam.) have been presented to the collembolan species Onychiurus sinensis (Hexapoda). The attractiveness and selectivity of the ten fungi was investigated taken into account the effect of the substrate on which the fungus was growing (malt-agar or litter) and the effect of fungal odour. Furthermore, moulting, growth, survival and reproduction of 0. sinensis in the presence of each of the ten test fungi were studied. Mucor plumbeus and Trichothecium roseum were the most preferred whatever the culture substrate and their odour was the most attractive. Two fungi (Penicillium spinulosum and the Basidiomycete S41) attracted Collembola by their odour but were not preferred as food sources. The animals could survive and reproduce on a mono-diet of several of our test fungi, but not on the Basidiomycete S41 and on Trichoderma polysporum.
Keywords: Collembola; feeding preferences; fungal odour; fungi; leaf litter