<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Urbieta, Itziar R</style></author><author><style face="normal" font="default" size="100%">Garcia, Luis V</style></author><author><style face="normal" font="default" size="100%">Zavala, MIGUEL a</style></author><author><style face="normal" font="default" size="100%">Marañón, Teodoro</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Mediterranean pine and oak distribution in southern Spain: Is there a mismatch between regeneration and adult distribution?</style></title><secondary-title><style face="normal" font="default" size="100%">Journal of Vegetation Science</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Distribution range</style></keyword><keyword><style  face="normal" font="default" size="100%">Holm oak</style></keyword><keyword><style  face="normal" font="default" size="100%">mediterranean forest</style></keyword><keyword><style  face="normal" font="default" size="100%">Niche expansion</style></keyword><keyword><style  face="normal" font="default" size="100%">Pinus spp.</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus spp.</style></keyword><keyword><style  face="normal" font="default" size="100%">regeneration dynamics</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2011</style></year></dates><publisher><style face="normal" font="default" size="100%">Blackwell Publishing Ltd</style></publisher><volume><style face="normal" font="default" size="100%">22</style></volume><pages><style face="normal" font="default" size="100%">18-31</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Questions: What is the current distribution of pine and oak species along environmental gradients in southern Spain? Do pine and oak regeneration niches differ from the environmental niches of adults? Is oak species regeneration favoured under the canopy of pine forests? Location: Forest areas of Andalusia (∼87 600 km2, southern Spain). Methods: We compiled extensive forest inventory data to explore differences in abundance (basal area, m2 ha−1) patterns of adults (dbh &gt;7.4 cm) and regeneration (dbh ≤7.4 cm) of five pine and five oak species. Canonical correspondence analysis (CCA) and generalized linear models were applied to explore species–environment relationships along climatic, edaphic, topographic and fire-frequency gradients. Results: Both pines and oaks segregated along complex environmental gradients, with pines generally dominating in more severe (colder and drier) environments, while oaks dominated in milder, wetter winter areas. In 40-55% of mature pine stands there was a lack of regeneration in the understorey, while in two oak species (Q. suber and Q. canariensis) 70% of stands did not show regeneration. Pine recruits were found at a higher frequency and abundance under the canopy of their congeners, whereas some oaks (Q. ilex) had greater regeneration under mixed pine–oak canopies. Conclusions: Climatic limitations and soil properties partly explained the regional distribution of pines and oaks. We found evidence for an upward shift of Q. ilex recruits towards areas with colder conditions in pine forests, which could be explained by a possible facilitative effect of the pine canopy on seedling establishment.</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Escudero, A.</style></author><author><style face="normal" font="default" size="100%">Mediavilla, S.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Decline in photosynthetic nitrogen use efficiency with leaf age and nitrogen resorption as determinants of leaf life span</style></title><secondary-title><style face="normal" font="default" size="100%">Journal of Ecology</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">leaf life span</style></keyword><keyword><style  face="normal" font="default" size="100%">N resorption</style></keyword><keyword><style  face="normal" font="default" size="100%">photosynthetic nitrogen use efficiency</style></keyword><keyword><style  face="normal" font="default" size="100%">Pinus spp.</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus spp</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2003</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2003///</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://dx.doi.org/10.1046/j.1365-2745.2003.00818.x</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">91</style></volume><pages><style face="normal" font="default" size="100%">880 - 889</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">* 1Cost-benefit models predict that leaf life span depends on its initial photosynthetic rate and construction cost and on the rate of decline in photosynthesis with age. Leaf gas exchange rates and N contents were measured in nine woody evergreen Mediterranean species with different leaf life spans to determine the effects of leaf ageing on photosynthetic N use efficiency (PNUE). N costs of leaf construction were assumed to be in part dependent on N resorption from senescing leaves. * 2Leaf ageing had significant negative effects on photosynthetic rates per unit leaf area. As N content per unit leaf area did not decline until the end of leaf life, PNUE also decreased with age. PNUE generally declined faster in species with a shorter leaf life span. There were no significant interspecific differences in maximum CO2 assimilation rates per unit leaf area and in N resorption that could be related to differences in leaf life span. * 3As PNUE decreases with leaf age, shedding of the older leaves and retranslocation of N to the current year's leaf biomass would result in an increase in the mean instantaneous efficiency of use of the N retranslocated. However, total CO2 assimilation can be improved by such shedding only when the increase in the efficiency of use of the remobilized N compensates for the remaining N lost in the shed leaves. * 4The photosynthesis of the old leaf cohorts exceeded the increase in photosynthesis that would be obtained from the N retranslocated to the younger leaves, given the observed efficiencies of N resorption. The retention of old leaves thus resulted in a higher whole-canopy CO2 assimilation, despite their low PNUE.</style></abstract><issue><style face="normal" font="default" size="100%">5</style></issue><notes><style face="normal" font="default" size="100%">The following values have no corresponding Zotero field:&lt;br/&gt;publisher: Blackwell Science Ltd</style></notes></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Escudero, a</style></author><author><style face="normal" font="default" size="100%">Mediavilla, S</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Decline in photosynthetic nitrogen use efficiency with leaf age and nitrogen resorption as determinants of leaf life span</style></title><secondary-title><style face="normal" font="default" size="100%">Journal of Ecology</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">leaf life span</style></keyword><keyword><style  face="normal" font="default" size="100%">N resorption</style></keyword><keyword><style  face="normal" font="default" size="100%">photosynthetic nitrogen use efficiency</style></keyword><keyword><style  face="normal" font="default" size="100%">Pinus spp.</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus spp</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2003</style></year></dates><publisher><style face="normal" font="default" size="100%">Blackwell Science Ltd</style></publisher><volume><style face="normal" font="default" size="100%">91</style></volume><pages><style face="normal" font="default" size="100%">880-889</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">* 1Cost-benefit models predict that leaf life span depends on its initial photosynthetic rate and construction cost and on the rate of decline in photosynthesis with age. Leaf gas exchange rates and N contents were measured in nine woody evergreen Mediterranean species with different leaf life spans to determine the effects of leaf ageing on photosynthetic N use efficiency (PNUE). N costs of leaf construction were assumed to be in part dependent on N resorption from senescing leaves. * 2Leaf ageing had significant negative effects on photosynthetic rates per unit leaf area. As N content per unit leaf area did not decline until the end of leaf life, PNUE also decreased with age. PNUE generally declined faster in species with a shorter leaf life span. There were no significant interspecific differences in maximum CO2 assimilation rates per unit leaf area and in N resorption that could be related to differences in leaf life span. * 3As PNUE decreases with leaf age, shedding of the older leaves and retranslocation of N to the current year's leaf biomass would result in an increase in the mean instantaneous efficiency of use of the N retranslocated. However, total CO2 assimilation can be improved by such shedding only when the increase in the efficiency of use of the remobilized N compensates for the remaining N lost in the shed leaves. * 4The photosynthesis of the old leaf cohorts exceeded the increase in photosynthesis that would be obtained from the N retranslocated to the younger leaves, given the observed efficiencies of N resorption. The retention of old leaves thus resulted in a higher whole-canopy CO2 assimilation, despite their low PNUE.</style></abstract></record></records></xml>