<?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></contributors><titles><title><style face="normal" font="default" size="100%">Contrasting effects of climate change along life stages of a dominant tree species: the importance of soil–climate interactions</style></title><secondary-title><style face="normal" font="default" size="100%">Diversity and Distributions</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2014</style></year></dates><pages><style face="normal" font="default" size="100%">n/a--n/a</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Aim For tree species, adult survival and seedling and sapling recruitment dynamics are the main processes that determine forest structure and composition. Thus, studying how these two life stages may be affected by climate change in the context of other abiotic and biotic variables is critical to understand future population trends. The aim of this study was to assess the sustainability of cork oak (Quercus suber) forests at the core of its distributional range under future climatic conditions. Location Southern Spain. Methods Using forest inventory data collected at two periods 10 years apart, we performed a comprehensive analysis to evaluate the role of different abiotic and biotic factors on adult survival and recruitment patterns. Results We found that both life stages were influenced by climatic conditions, but in different ways. Adult tree survival was negatively impacted by warmer spring temperatures, while recruitment was positively affected by warmer winter temperatures. Our results also revealed the importance of soil texture as a modulator of winter precipitation effects on adult survival. With higher winter precipitation, adult survival increased in sandy soils and decreased in clayish soils. Therefore, under predicted future climate scenarios of wetter winters and warmer temperatures, the presence of cork oaks is more likely to occur in sandy soils vs. clayish soils. Biotic conditions also affected these life stages. We found a negative effect of heterospecific but not conspecific trees on both adult survival and seedling recruitment. Main conclusions Overall, the sustainability of the studied forests will be highly dependent not only on future climatic trends, but also on their interaction with other key factors – soil properties in particular – that modulate the effects of climate on demographic rates.</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%">Ibáñez, Beatriz</style></author><author><style face="normal" font="default" size="100%">Serrano, María S.</style></author><author><style face="normal" font="default" size="100%">De Vita, Paolo</style></author><author><style face="normal" font="default" size="100%">Avila, José M.</style></author><author><style face="normal" font="default" size="100%">Pérez-Ramos, Ignacio M.</style></author><author><style face="normal" font="default" size="100%">García, Luis V.</style></author><author><style face="normal" font="default" size="100%">Esperanza Sánchez, M.</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%">Spatial patterns of soil pathogens in declining Mediterranean forests: implications for tree species regeneration.</style></title><secondary-title><style face="normal" font="default" size="100%">The New phytologist</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Biological</style></keyword><keyword><style  face="normal" font="default" size="100%">Forest decline</style></keyword><keyword><style  face="normal" font="default" size="100%">Host-Pathogen Interactions</style></keyword><keyword><style  face="normal" font="default" size="100%">Mediterranean Region</style></keyword><keyword><style  face="normal" font="default" size="100%">Models</style></keyword><keyword><style  face="normal" font="default" size="100%">neighborhood models</style></keyword><keyword><style  face="normal" font="default" size="100%">Phytophthora</style></keyword><keyword><style  face="normal" font="default" size="100%">Phytophthora: physiology</style></keyword><keyword><style  face="normal" font="default" size="100%">Pythium</style></keyword><keyword><style  face="normal" font="default" size="100%">Pythium: physiology</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus suber</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus: microbiology</style></keyword><keyword><style  face="normal" font="default" size="100%">regeneration dynamics</style></keyword><keyword><style  face="normal" font="default" size="100%">Seedling</style></keyword><keyword><style  face="normal" font="default" size="100%">Seedling: microbiology</style></keyword><keyword><style  face="normal" font="default" size="100%">Soil Microbiology</style></keyword><keyword><style  face="normal" font="default" size="100%">soil texture</style></keyword><keyword><style  face="normal" font="default" size="100%">soil-borne pathogens</style></keyword><keyword><style  face="normal" font="default" size="100%">species coexistence</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2012</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2012///</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/22428751</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">194</style></volume><pages><style face="normal" font="default" size="100%">1014 - 1024</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Soil-borne pathogens are a key component of the belowground community because of the significance of their ecological and socio-economic impacts. However, very little is known about the complexity of their distribution patterns in natural systems. Here, we explored the patterns, causes and ecological consequences of spatial variability in pathogen abundance in Mediterranean forests affected by oak decline. We used spatially explicit neighborhood models to predict the abundance of soil-borne pathogen species (Phytophthora cinnamomi, Pythium spiculum and Pythium spp.) as a function of local abiotic conditions (soil texture) and the characteristics of the tree and shrub neighborhoods (species composition, size and health status). The implications of pathogen abundance for tree seedling performance were explored by conducting a sowing experiment in the same locations in which pathogen abundance was quantified. Pathogen abundance in the forest soil was not randomly distributed, but exhibited spatially predictable patterns influenced by both abiotic and, particularly, biotic factors (tree and shrub species). Pathogen abundance reduced seedling emergence and survival, but not in all sites or tree species. Our findings suggest that heterogeneous spatial patterns of pathogen abundance at fine spatial scale can be important for the dynamics and restoration of declining Mediterranean forests.</style></abstract><issue><style face="normal" font="default" size="100%">4</style></issue><notes><style face="normal" font="default" size="100%">The following values have no corresponding Zotero field:&lt;br/&gt;accession-num: 22428751</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%">Gómez-Aparicio, LORENA</style></author><author><style face="normal" font="default" size="100%">GARCÍA-VALDÉS, Raúl</style></author><author><style face="normal" font="default" size="100%">Ruíz-Benito, PALOMA</style></author><author><style face="normal" font="default" size="100%">Zavala, MIGUEL a</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Disentangling the relative importance of climate, size and competition on tree growth in Iberian forests: implications for forest management under global change</style></title><secondary-title><style face="normal" font="default" size="100%">Global Change Biology</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">2 march 2011</style></keyword><keyword><style  face="normal" font="default" size="100%">climate change</style></keyword><keyword><style  face="normal" font="default" size="100%">competitive effect</style></keyword><keyword><style  face="normal" font="default" size="100%">competitive response</style></keyword><keyword><style  face="normal" font="default" size="100%">Forests</style></keyword><keyword><style  face="normal" font="default" size="100%">iberian peninsula</style></keyword><keyword><style  face="normal" font="default" size="100%">march 2011 and accepted</style></keyword><keyword><style  face="normal" font="default" size="100%">maximum likelihood</style></keyword><keyword><style  face="normal" font="default" size="100%">Mediterranean</style></keyword><keyword><style  face="normal" font="default" size="100%">Mediterranean forests</style></keyword><keyword><style  face="normal" font="default" size="100%">neighhorbood models</style></keyword><keyword><style  face="normal" font="default" size="100%">received 21 october 2010</style></keyword><keyword><style  face="normal" font="default" size="100%">revised version received 1</style></keyword><keyword><style  face="normal" font="default" size="100%">species rank reversals</style></keyword><keyword><style  face="normal" font="default" size="100%">tree coexistence</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2011</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2011///</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://dx.doi.org/10.1111/j.1365-2486.2011.02421.xhttp://doi.wiley.com/10.1111/j.1365-2486.2011.02421.x</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">17</style></volume><pages><style face="normal" font="default" size="100%">2400 - 2414</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Most large-scale multispecies studies of tree growth have been conducted in tropical and cool temperate forests, whereas Mediterranean water-limited ecosystems have received much less attention. This limits our understanding of how growth of coexisting tree species varies along environmental gradients in these forests, and the implications for species interactions and community assembly under current and future climatic conditions. Here, we quantify the absolute effect and relative importance of climate, tree size and competition as determinants of tree growth patterns in Iberian forests, and explore interspecific differences in the two components of competitive ability (competitive response and effect) along climatic and size gradients. Spatially explicit neighborhood models were developed to predict tree growth for the 15 most abundant Iberian tree species using permanent-plot data from the Spanish Second and Third National Forest Inventory (IFN). Our neighborhood analyses showed a climatic and size effect on tree growth, but also revealed that competition from neighbors has a comparatively much larger impact on growth in Iberian forests. Moreover, the sensitivity to competition (i.e. competitive response) of target trees varied markedly along climatic gradients causing significant rank reversals in species performance, particularly under xeric conditions. We also found compelling evidence for strong species-specific competitive effects in these forests. Altogether, these results constitute critical new information which not only furthers our understanding of important theoretical questions about the assembly of Mediterranean forests, but will also be of help in developing new guidelines for adapting forests in this climatic boundary to global change. If we consider the climatic gradients of this study as a surrogate for future climatic conditions, then we should expect absolute growth rates to decrease and sensitivity to competition to increase in most forests of the Iberian Peninsula (in all but the northern Atlantic forests), making these management considerations even more important in the future.</style></abstract><issue><style face="normal" font="default" size="100%">7</style></issue><notes><style face="normal" font="default" size="100%">The following values have no corresponding Zotero field:&lt;br/&gt;publisher: Blackwell Publishing 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%">García, Luis V.</style></author><author><style face="normal" font="default" size="100%">Ramo, Cristina</style></author><author><style face="normal" font="default" size="100%">Aponte, Cristina</style></author><author><style face="normal" font="default" size="100%">Moreno, Adela</style></author><author><style face="normal" font="default" size="100%">Domínguez, María T.</style></author><author><style face="normal" font="default" size="100%">Gómez-Aparicio, LORENA</style></author><author><style face="normal" font="default" size="100%">Redondo, Ramón</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%">Protected wading bird species threaten relict centenarian cork oaks in a Mediterranean Biosphere Reserve: A conservation management conflict</style></title><secondary-title><style face="normal" font="default" size="100%">Biological Conservation</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Colonial waterbirds</style></keyword><keyword><style  face="normal" font="default" size="100%">d13C</style></keyword><keyword><style  face="normal" font="default" size="100%">d15N</style></keyword><keyword><style  face="normal" font="default" size="100%">Doñana</style></keyword><keyword><style  face="normal" font="default" size="100%">Heronry</style></keyword><keyword><style  face="normal" font="default" size="100%">Indirect effects</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus suber</style></keyword><keyword><style  face="normal" font="default" size="100%">Stable isotopes</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2011</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2011///</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://linkinghub.elsevier.com/retrieve/pii/S000632071000474X</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">144</style></volume><pages><style face="normal" font="default" size="100%">764 - 771</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Conservation management conﬂicts frequently arise when an overpopulation of a protected organism has negative effects on other valuable elements in the same ecosystem. We studied the interactions between a colony of protected tree-nesting wading birds and a remnant population of centenarian cork oaks that was part of the formerly dominant forests in the Doñana Biological Reserve (SW Spain). A signiﬁcant increase in the tree mortality rates has been recorded in areas that are yearly inﬂuenced by the bird colony. We analysed a cohort of surviving trees using a gradient of nesting bird inﬂuence. Tree-nesting history, bird isotopic signature (d 15 N), tree health-related parameters (defoliation, d 13 C and leaf surface coverage by faeces) and several soil variables were evaluated. Bird inﬂuence was related to increased soil salinity. This increase correlated to increased water-use efﬁciency for the leaves and to crown defoliation, suggesting that the heavily occupied trees are under higher stress and in poorer health condition than the unoccupied ones. We tested structural equations models (SEM) that were based on hypothesised bird effects on the health of the trees. Soil-mediated effects of the nesting birds best explained the symptoms of the declining health of the trees, whereas the percent of leaves’ surface that was covered by faeces did not improve the ﬁtted SEM model. For the reserve’s managers, a challenging trade-off exists between preserving the relict trees, which have a high genetic diversity and a key ecological role in these savannah-like ecosystems, and maintaining the current nesting area for these protected, but expanding, wading birds.</style></abstract><issue><style face="normal" font="default" size="100%">2</style></issue></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors></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><dates><year><style  face="normal" font="default" size="100%">2009</style></year></dates><publisher><style face="normal" font="default" size="100%">ECOLOGICAL SOC AMER</style></publisher><pub-location><style face="normal" font="default" size="100%">1990 M STREET NW, STE 700, WASHINGTON, DC 20036 USA</style></pub-location><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></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><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors></contributors><titles><title><style face="normal" font="default" size="100%">Differential light responses of Mediterranean tree saplings: linking ecophysiology with regeneration niche in four co-occurring species</style></title><secondary-title><style face="normal" font="default" size="100%">Tree Physiology</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2006</style></year></dates><volume><style face="normal" font="default" size="100%">26</style></volume><pages><style face="normal" font="default" size="100%">947-958</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The ecophysiological mechanisms underlying plant–plant interactions and forest regeneration processes in Mediterranean ecosystems are poorly understood, and the experimental evidence for the role of light availability in these processes is particularly scant. We analyzed the effects of high and low irradiances on 31 ecological, morphological and physiological variables in saplings of four late-successional Mediterranean trees, two deciduous (Acer opalus subsp. granatense (Boiss.) Font Quer &amp; Rothm. and Quercus pyrenaica Willd.) and two evergreen (Pinus nigra Arnold subsp. salzmannii (Dunal) Franco and Quercus ilex L.), which coexist in mature montane forests. Species differed in both their capacity to withstand high radiation and in their shade tolerance. The two deciduous species were the least tolerant to high radiation, exhibiting both dynamic and chronic photoinhibition in full sunlight, with severe implications for gas exchange and photosynthetic performance. Excess light severely limited the survival of A. opalus subsp. granatense, even minor reductions of excessive radiation (from full sunlight to 80% sunlight) being crucial for sapling survival. Among species, P. nigra was the most tolerant of high irradiances but showed the poorest shade acclimation. Interspecific differences in the mechanisms of response to light provide a partial explanation of the differential regeneration patterns previously reported for these species, with shade-tolerant plants (i.e., deciduous broadleaf species) benefiting the most from associations with nurse plants. We conclude that light availability is an important environmental factor defining the regeneration niche of Mediterranean woody species.</style></abstract><notes><style face="normal" font="default" size="100%">10.1093/treephys/26.7.947</style></notes><research-notes><style face="normal" font="default" size="100%">10.1093/treephys/26.7.947</style></research-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%">Gómez-Aparicio, LORENA</style></author><author><style face="normal" font="default" size="100%">Gómez, Jose M.</style></author><author><style face="normal" font="default" size="100%">Zamora, Regino</style></author><author><style face="normal" font="default" size="100%">Boettinger, Janis L.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Canopy vs. soil effects of shrubs facilitating tree seedlings in Mediterranean montane ecosystems</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%">Nurse shrub</style></keyword><keyword><style  face="normal" font="default" size="100%">Positive interaction</style></keyword><keyword><style  face="normal" font="default" size="100%">Potassium</style></keyword><keyword><style  face="normal" font="default" size="100%">Removal experiment</style></keyword><keyword><style  face="normal" font="default" size="100%">shade</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2005</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2005///</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://dx.doi.org/10.1111/j.1654-1103.2005.tb02355.x</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">16</style></volume><pages><style face="normal" font="default" size="100%">191 - 198</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Abstract. Question: Is the facilitative effect of nurse shrubs on early recruitment of trees mediated by a ‘canopy effect’(microclimate amelioration and protection from herbivores), a ‘soil effect’(modification of soil properties), or both? Location: Two successional montane shrublands at the Sierra Nevada Protected Area, SE Spain. Method: Seedlings of Quercus and Pinus species were planted in four experimental treatments: (1) under shrubs; (2) in open interspaces without vegetation; (3) under shrubs where the canopies were removed; (4) in open interspaces but covering seedlings with branches, mimicking a shrub canopy. Results: Both effects benefited seedling performance. However, microclimatic amelioration due to canopy shading had the strongest effect, which was particularly pronounced in the drier site. Below-ground, shrubs did not modify soil physical characteristics, organic matter, total N and P, or water content, but significantly increased available K, which has been shown to improve seedling water-use efficiency under drought conditions. Conclusions: We propose that in Mediterranean montane ecosystems, characterised by a severe summer drought, pioneer shrubs represent a major safe site for tree early recruitment during secondary succession, improving seedling survival during summer by the modification of both the above-and below-ground environment.</style></abstract><issue><style face="normal" font="default" size="100%">2</style></issue><notes><style face="normal" font="default" size="100%">The following values have no corresponding Zotero field:&lt;br/&gt;publisher: Blackwell Publishing Ltd</style></notes></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors></contributors><titles><title><style face="normal" font="default" size="100%">Response of tree seedlings to the abiotic heterogeneity generated by nurse shrubs: an experimental approach at different scales</style></title><secondary-title><style face="normal" font="default" size="100%">Ecography</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2005</style></year></dates><publisher><style face="normal" font="default" size="100%">Munksgaard International Publishers</style></publisher><volume><style face="normal" font="default" size="100%">28</style></volume><pages><style face="normal" font="default" size="100%">757-768</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Spatial heterogeneity of abiotic factors influences patterns of seedling establishment at different scales. In stress-prone ecosystems such as Mediterranean ones, heterogeneity generated by shrubs has been shown to facilitate the establishment of tree species. However, how this facilitation is affected by spatial scale remains poorly understood. We have experimentally analysed the consequences of the abiotic heterogeneity generated by pioneer shrubs on survival, growth and physiology of seedlings of three important tree species from Mediterranean mountains (Acer opalus ssp. granatense, Quercus pyrenaica and Quercus ilex). Patterns of abiotic heterogeneity and seedling performance were studied at two scales differing in grain: 1) the microhabitat scale, by using open interspaces as controls of the effect of different shrub species, and 2) the microsite scale, analysing the effects of fine-grain heterogeneity (within-microhabitat heterogeneity). Results showed that, at the microhabitat scale, seedling establishment of the three tree species significantly benefited from the modification of the abiotic environment by nurse shrubs. However, we found shrub-seedling interactions to be species-specific, due to differential modification of both aboveground (light availability) and belowground (soil compaction, water content, and fertility) abiotic factors by nurse shrub species. Heterogeneity at the within-microhabitat scale was rather high, although it did not significantly affect seedling performance of any of the tree species. The study demonstrates that the effects of the abiotic heterogeneity generated by shrubs are not consistent across the range of spatial scales considered. The regeneration niche of tree species becomes very complex at fine spatial scales, and thereby estimators of abiotic heterogeneity are valuable descriptors of spatial patterns of seedling establishment only when microsite “noise” is averaged out at greater scales.</style></abstract></record></records></xml>