<?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%">Puerta-Piñero, Carolina</style></author><author><style face="normal" font="default" size="100%">Gómez, Jose M.</style></author><author><style face="normal" font="default" size="100%">Valladares, Fernando</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Irradiance and oak seedling survival and growth in a heterogeneous environment</style></title><secondary-title><style face="normal" font="default" size="100%">Forest Ecology and Management</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">light environment</style></keyword><keyword><style  face="normal" font="default" size="100%">Mediterranean Region</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus ilex</style></keyword><keyword><style  face="normal" font="default" size="100%">seedling performance</style></keyword><keyword><style  face="normal" font="default" size="100%">spatial heterogeneity</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2007</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2007///</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://linkinghub.elsevier.com/retrieve/pii/S0378112707000874</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">242</style></volume><pages><style face="normal" font="default" size="100%">462 - 469</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The Mediterranean region emerges highly heterogeneous at every spatio-temporal scale. Key species shape a mosaic of patches (landscape units) composed of different microhabitats. Within these ecosystems irradiance appears as one of the most changing factors affecting communities’ dynamic. However, the impact of irradiance on the species performance is still poorly known. In this study, we intended to explore whether irradiance heterogeneity inﬂuences early recruitment. We chose a patchy Mediterranean site. During 2001, 2002 and 2003 we marked naturally Quercus ilex emerged seedlings. We distinguished three landscape units (Q. ilex woodlands, shrublands and afforestations) and six microhabitats (oak, broom, tall shrub, subshrub, pine and open). For each seedling, we measured (1) irradiance as global site factor (GSF); (2) acorn presence; (3) acorn depth; (4) burial layer; (5) distance to the nearest co-speciﬁc adult. As estimates of seedling performance, we measured seedling survival and height. Estimates of seedling performance were higher in 2001 and 2002 than in 2003. Oak or pine microhabitats achieved higher survival rates than brooms or open areas whilst under oaks, brooms or in open areas seedling height was lower than under tall shrubs. Irradiance signiﬁcantly affected seedling survival and growth. The lower the irradiance, the higher the survival. Maximal growth was found at intermediate irradiance, indicating that, in this system, moderate shade is crucial for Q. ilex seedling recruitment. Some microhabitats provide intermediate irradiance that combines positive effects on survival and growth. As a ﬁnal point, dispersers’ activity creates a heterogeneous distribution of acorn deposition ﬁltering out part of the total irradiance present in the study site.</style></abstract><issue><style face="normal" font="default" size="100%">2-3</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%">Irradiance and oak seedling survival and growth in a heterogeneous environment</style></title><secondary-title><style face="normal" font="default" size="100%">Forest Ecology and Management</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2007</style></year></dates><volume><style face="normal" font="default" size="100%">242</style></volume><pages><style face="normal" font="default" size="100%">462-469</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The Mediterranean region emerges highly heterogeneous at every spatio-temporal scale. Key species shape a mosaic of patches (landscape units) composed of different microhabitats. Within these ecosystems irradiance appears as one of the most changing factors affecting communities’ dynamic. However, the impact of irradiance on the species performance is still poorly known. In this study, we intended to explore whether irradiance heterogeneity inﬂuences early recruitment. We chose a patchy Mediterranean site. During 2001, 2002 and 2003 we marked naturally Quercus ilex emerged seedlings. We distinguished three landscape units (Q. ilex woodlands, shrublands and afforestations) and six microhabitats (oak, broom, tall shrub, subshrub, pine and open). For each seedling, we measured (1) irradiance as global site factor (GSF); (2) acorn presence; (3) acorn depth; (4) burial layer; (5) distance to the nearest co-speciﬁc adult. As estimates of seedling performance, we measured seedling survival and height. Estimates of seedling performance were higher in 2001 and 2002 than in 2003. Oak or pine microhabitats achieved higher survival rates than brooms or open areas whilst under oaks, brooms or in open areas seedling height was lower than under tall shrubs. Irradiance signiﬁcantly affected seedling survival and growth. The lower the irradiance, the higher the survival. Maximal growth was found at intermediate irradiance, indicating that, in this system, moderate shade is crucial for Q. ilex seedling recruitment. Some microhabitats provide intermediate irradiance that combines positive effects on survival and growth. As a ﬁnal point, dispersers’ activity creates a heterogeneous distribution of acorn deposition ﬁltering out part of the total irradiance present in the study site.</style></abstract></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>