<?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%">Barba, Josep</style></author><author><style face="normal" font="default" size="100%">Yuste, Jorge Curiel</style></author><author><style face="normal" font="default" size="100%">Martínez-Vilalta, Jordi</style></author><author><style face="normal" font="default" size="100%">Lloret, Francisco</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Drought-induced tree species replacement is reflected in the spatial variability of soil respiration in a mixed Mediterranean forest</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%">Forest dieback</style></keyword><keyword><style  face="normal" font="default" size="100%">Mediterranean ecosystem</style></keyword><keyword><style  face="normal" font="default" size="100%">Pinus sylvestris</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus ilex</style></keyword><keyword><style  face="normal" font="default" size="100%">Soil CO2 efflux</style></keyword><keyword><style  face="normal" font="default" size="100%">Spatial variability</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2013</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2013///</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://www.sciencedirect.com/science/article/pii/S0378112713003939</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">306</style></volume><pages><style face="normal" font="default" size="100%">79 - 87</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">As episodes of drought-induced forest mortality are being increasingly reported worldwide and may become more frequent in the future as a result of climate change, it is essential to characterize their functional implications in terms of ecosystem carbon and water fluxes. We investigated the spatial variability of soil respiration in a mixed Mediterranean forest located on rugged terrain, where Scots pine (Pinus sylvestris) is affected by drought-induced dieback and appears to have been replaced by Holm oak (Quercus ilex) as the dominant tree species. Soil respiration was measured in spring 2010 on two plots (16.2 × 16.2 m) using a static closed chamber method (soda lime technique) and a systematic sampling (1.8-m grid) including 100 points per plot. Biotic and abiotic variables, such as soil moisture, soil temperature, soil organic matter content, stoniness, pH, fine root C:N ratio and biomass, tree basal area and tree species and health condition of nearest neighbouring tree were also recorded. Our results showed that the spatial variability of soil respiration under optimal environmental conditions (spring) was high and showed no spatial autocorrelation on the scale studied (1–18 m). A mixed-effects model applied to explain the spatial variability of soil respiration indicated that only the variables related to forest structure (i.e., health condition and basal area) explained any of the observed variability of soil respiration (R2 = 0.45). Our model revealed that soil respiration was highest in soils close to dead pines and under Holm oak trees, suggesting that tree mortality and species replacement of pine trees by Holm oak may lead to higher soil respiration fluxes. The direct effect of tree mortality on soil respiration may be a transitory response caused by fine root mortality. Furthermore, the fact that tree species replacement as a result of drought-induced die-off is accompanied by concomitant changes in soil respiration has important implications for soil and ecosystem carbon balance</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%">Galiano, Lucía</style></author><author><style face="normal" font="default" size="100%">Martínez-Vilalta, Jordi</style></author><author><style face="normal" font="default" size="100%">Eugenio, Màrcia</style></author><author><style face="normal" font="default" size="100%">Granzow-de la Cerda, Íñigo</style></author><author><style face="normal" font="default" size="100%">Lloret, Francisco</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Seedling emergence and growth of Quercus spp. following severe drought effects on a Pinus sylvestris canopy</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%">Canopy gap</style></keyword><keyword><style  face="normal" font="default" size="100%">Extreme climatic episode</style></keyword><keyword><style  face="normal" font="default" size="100%">Pinus sylvestris</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus humilis</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus ilex</style></keyword><keyword><style  face="normal" font="default" size="100%">seedling growth</style></keyword><keyword><style  face="normal" font="default" size="100%">Seedling recruitment</style></keyword><keyword><style  face="normal" font="default" size="100%">tree mortality</style></keyword><keyword><style  face="normal" font="default" size="100%">Vegetation shift</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://dx.doi.org/10.1111/j.1654-1103.2012.01485.x</style></url></web-urls></urls><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%">Questions We addressed the following questions: (1) did defoliation and die-off of the dominant Pinus sylvestris, induced by an extreme drought episode, favour emergence of other tree species; (2) did the defoliated canopies of P. sylvestris resulting from drought promote radial growth among other pre-existing tree species seedlings under them? Location P. sylvestris forest in Central Pyrenees (NE Spain) affected by a severe drought in 2004–2005. Methods Despite increased focus on climate-related forest die-off, studies of the effects on regeneration processes following extreme drought remain scarce. We analysed whether an episode of drought-induced mortality on the dominant P. sylvestris L. may act as a driver of vegetation shift. Seedlings of Quercus humilis Mill. and Q. ilex L. from 27 plots were sampled under P. sylvestris canopies with &lt;50% and ≥50% defoliation (standing dead trees included) to determine age distribution and radial growth using a retrospective, dendrochronological approach. Results Drought-induced canopy losses appear not to be compensated by regeneration of P. sylvestris. Recruitment of below-canopy tree species (specifically Q. humilis and Q. ilex) that could potentially become dominant was high in the entire studied area. However, the spatial patterns of Quercus spp. regeneration following the 2004–2005 drought were complex. While the emergence of new Quercus spp. seedlings was reduced under open, drought-induced canopies, growth of seedlings already established was favoured in open-canopy conditions. Conclusions Although the effects of extreme drought events may disfavour the establishment of new recruits, enhanced growth responses of a pre-established seedling bank could still contribute to accelerate forest dynamics under drier conditions. Because of the predicted increases in intensity and frequency of extreme droughts, monitoring studies are key to elucidate whether the initial patterns observed will be maintained in the long term, eventually leading to a vegetation shift.</style></abstract></record></records></xml>