<?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%">Madrigal-González, Jaime</style></author><author><style face="normal" font="default" size="100%">García-Rodríguez, José a.</style></author><author><style face="normal" font="default" size="100%">Zavala, Miguel A.</style></author></authors><secondary-authors><author><style face="normal" font="default" size="100%">Pugnaire, Francisco</style></author></secondary-authors></contributors><titles><title><style face="normal" font="default" size="100%">Shrub encroachment shifts the bioclimatic limit between marcescent and sclerophyllous oaks along an elevation gradient in west-central Spain</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%">Bioclimatic limit</style></keyword><keyword><style  face="normal" font="default" size="100%">Elevation gradient</style></keyword><keyword><style  face="normal" font="default" size="100%">Oak trees</style></keyword><keyword><style  face="normal" font="default" size="100%">Regeneration</style></keyword><keyword><style  face="normal" font="default" size="100%">Shrub encroachment</style></keyword><keyword><style  face="normal" font="default" size="100%">Species distribution</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2014</style></year></dates><volume><style face="normal" font="default" size="100%">25</style></volume><pages><style face="normal" font="default" size="100%">514-524</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Questions (1) Does shrub encroachment affect the regeneration of two contrasting species of oak along an elevation gradient in the west-central Iberian Peninsula? (2) Do different nurse shrubs have any relevant species-specific effects along the gradient? (3) Does shrub encroachment affect the location of the bioclimatic limit between these two oak species along the elevation gradient? Location Twelve sites distributed from the Arribes del Duero plains to the Sistema Central mountains (Salamanca province, Spain). Methods We measured the regeneration of two contrasting oak tree species (Quercus ilex subsp. ballota Samp - sclerophyllous, Q.pyrenaica Willd - marcescent) as the relative percentage cover of seedlings and saplings (&lt;1.3-m high) in plots 10m in diameter distributed in stands of different age. We fixed the bioclimatic limit at 50% relative proportion of species in each plot, i.e. whether one species was more abundant than the other in a plot. Shrub stand age was estimated by counting growth rings in the principal stems of the oldest shrubs in a plot. We fitted generalized linear mixed models to analyse the effects of elevation, specific nurse shrub and shrub stand age on regeneration and the probability of one species being more abundant than the other. Results The regeneration and relative proportion of Q.ilex (sclerophyllous) decreased with elevation. Regeneration did not vary with shrub encroachment, although the relative proportion increased notably in the youngest stands. In turn, regeneration and relative proportion of Q.pyrenaica (deciduous) significantly increased towards the upper sites and mature shrub stands. We found no evidence of specific nurse shrub effects on regeneration or the probability of one species being more abundant than the other in either of the two species of oak. Conclusions The bioclimatic limit between the two contrasting species of oak shifted with shrub stand age along the elevation gradient. Land practices preventing shrub encroachment can thus indirectly shift this limit towards higher elevations. The effects of shrubs may be critical in resolving the climatic and land-use effects on elevation shifts of species under changing conditions in bioclimatic transitions.</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%">Gómez-Aparicio, LORENA</style></author><author><style face="normal" font="default" size="100%">Zavala, Miguel A.</style></author><author><style face="normal" font="default" size="100%">Bonet, Francisco J.</style></author><author><style face="normal" font="default" size="100%">Zamora, Regino</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Are pine plantations valid tools for restoring Mediterranean forests? An assessment along abiotic and biotic gradients</style></title><secondary-title><style face="normal" font="default" size="100%">ECOLOGICAL APPLICATIONS</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">competition</style></keyword><keyword><style  face="normal" font="default" size="100%">environmental gradients</style></keyword><keyword><style  face="normal" font="default" size="100%">Facilitation</style></keyword><keyword><style  face="normal" font="default" size="100%">management strategy</style></keyword><keyword><style  face="normal" font="default" size="100%">Mediterranean forests</style></keyword><keyword><style  face="normal" font="default" size="100%">pine plantations</style></keyword><keyword><style  face="normal" font="default" size="100%">Regeneration</style></keyword><keyword><style  face="normal" font="default" size="100%">seed dispersal</style></keyword><keyword><style  face="normal" font="default" size="100%">species diversity</style></keyword><keyword><style  face="normal" font="default" size="100%">stand density</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2009</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2009///</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">19</style></volume><pages><style face="normal" font="default" size="100%">2124 - 2141</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The ecological impacts of forest plantations are a focus of intense debate, from studies that consider plantations as ``biological deserts{''} to studies showing positive effects on plant diversity and dynamics. This lack of consensus might be influenced by the scarcity of studies that examine how the ecological characteristics of plantations vary along abiotic and biotic gradients. Here we conducted a large-scale assessment of plant regeneration and diversity in plantations of southern Spain. Tree seedling and sapling density, plant species richness, and Shannon's (H') diversity index were analyzed in 442 pine plantation plots covering a wide gradient of climatic conditions, stand density, and distance to natural forests that act as seed sources. Pronounced variation in regeneration and diversity was found in plantation understories along the gradients explored. Low-to mid-altitude plantations showed a diverse and abundant seedling bank dominated by Quercus ilex, whereas high-altitude plantations showed a virtually monospecific seeding bank of Pinus sylvestris. Regeneration was null in plantations with stand densities exceeding 1500 pines/ha. Moderate plantation densities (500-1000 pines/ha) promoted recruitment in comparison to low or null canopy cover, suggesting the existence of facilitative interactions. Quercus ilex recruitment diminished exponentially with distance to the nearest Q. ilex forest. Richness and H' index values showed a hump-shaped distribution along the altitudinal and radiation gradients and decreased monotonically along the stand density gradient. From a management perspective, different strategies will be necessary depending on where a plantation lies along the gradients explored. Active management will be required in high-density plantations with arrested succession and low diversity. Thinning could redirect plantations toward more natural densities where facilitation predominates. Passive management might be recommended for low-to moderate-density plantations with active successional dynamics (e. g., toward oak or pine-oak forests at low to mid altitudes). Enrichment planting will be required to overcome seed limitation, especially in plantations far from natural forests. We conclude that plantations should be perceived as dynamic systems where successional trajectories and diversity levels are determined by abiotic constraints, complex balances of competitive and facilitative interactions, the spatial configuration of native seed sources, and species life-history traits.</style></abstract><issue><style face="normal" font="default" size="100%">8</style></issue><notes><style face="normal" font="default" size="100%">The following values have no corresponding Zotero field:&lt;br/&gt;pub-location: 1990 M STREET NW, STE 700, WASHINGTON, DC 20036 USA&lt;br/&gt;publisher: ECOLOGICAL SOC AMER</style></notes></record></records></xml>