<?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%">Abades, R</style></author><author><style face="normal" font="default" size="100%">Gaxiola, Aurora</style></author><author><style face="normal" font="default" size="100%">Marquet, Pablo A</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Fire , percolation thresholds and the savanna forest transition : a neutral model approach</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%">fire</style></keyword><keyword><style  face="normal" font="default" size="100%">neutral model</style></keyword><keyword><style  face="normal" font="default" size="100%">percolation</style></keyword><keyword><style  face="normal" font="default" size="100%">plant population and community dynamics</style></keyword><keyword><style  face="normal" font="default" size="100%">savanna forest transition</style></keyword><keyword><style  face="normal" font="default" size="100%">threshold</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2014</style></year></dates><pages><style face="normal" font="default" size="100%">1386-1393</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">1. Recent empirical and theoretical analyses have suggested that biomes could correspond to alterna- tive equilibrium states; one such example is the transition between forest, savanna and treeless states. 2. Fire supposes to be a key functional component of savanna ecosystems and is a powerful predic- tor of tree cover that can differentiate between forest and savanna ecosystems. Interestingly, empiri- cal evidence suggests that fire occurrence drops at a threshold tree cover near 40%. Since savannas are ecosystems characterized by a discontinuous tree canopy cover immersed in a continuous grass layer a 40% of tree cover implies around 60% cover of grasses, which are the flammable component of this ecosystem. 3. In this article, we hypothesize that the observed common pattern of 40% tree cover versus 60% in grass cover often reported for savanna ecosystems is the outcome of a spatial phase transition associated with the existence of a critical percolation threshold for fire spread. 4. To test this hypothesis, we developed a spatially explicit neutral metacommunity model to explore the relationship between species cover and the emergence of percolation patterns. The model is intended to emulate savanna dynamics under neutrality assumptions. 5. Using a statistical mechanical approach, we show that a second-order phase transition behaviour is observed for the probability that a grass species develops a percolating cluster. Using a simple finite size scaling analysis, the percolation threshold pc for our model was estimated to be in the range of 0.53–0.62. 6. Synthesis. Our results point out that the emergence of a spatial phase transition associated with percolation is a robust result of neutral metacommunity dynamics with a critical threshold of space occupancy close to pc ~ 0.6, which supports our hypothesis that the empirically observed 40% tree cover (60% grass cover) is associated with a percolation threshold for C4 grasses that in turn imply the existence of a spatially connected or spanning cluster of grass cover over which fire can spread.</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%">GARCÍA-VALDÉS, Raúl</style></author><author><style face="normal" font="default" size="100%">Zavala, Miguel A.</style></author><author><style face="normal" font="default" size="100%">Araújo, Miguel B.</style></author><author><style face="normal" font="default" size="100%">Purves, Drew W.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Chasing a moving target: projecting climate change-induced shifts in non-equilibrial tree species distributions</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%">Bayesian statistics</style></keyword><keyword><style  face="normal" font="default" size="100%">Iberian forests</style></keyword><keyword><style  face="normal" font="default" size="100%">local colonization and extinction rates</style></keyword><keyword><style  face="normal" font="default" size="100%">MCMC</style></keyword><keyword><style  face="normal" font="default" size="100%">metapopulation model</style></keyword><keyword><style  face="normal" font="default" size="100%">plant population and community dynamics</style></keyword><keyword><style  face="normal" font="default" size="100%">plant–climate interactions</style></keyword><keyword><style  face="normal" font="default" size="100%">seed dispersal</style></keyword><keyword><style  face="normal" font="default" size="100%">species distribution models</style></keyword><keyword><style  face="normal" font="default" size="100%">stochastic patch occupancy models</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://dx.doi.org/10.1111/1365-2745.12049</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%">* The geographic distributions of plant species show marked correlations with the current climate, suggesting that they are likely to shift if climate changes. However, before projecting any such shifts, it is important to establish whether distributions are at equilibrium with the current climate. If they are not, distributional shifts could occur even without climate change, making it difficult to tease apart climate-induced shifts from shifts occurring naturally without climate change. * We forecast the geographical distributions of the 10 most common trees occurring in the Iberian Peninsula using a new method that relaxes the species–climate equilibrium assumption implicit in most species distributions models. For each species, we developed a spatially explicit patch occupancy model (SPOM) with climate-dependent extinction rates and with colonization rates that depend on both climate and local seed dispersal. Bayesian methods were used to estimate the colonization, extinction and seed dispersal functions against observed colonization and extinction events recorded in repeat surveys of 46 596 forest plots in the Spanish Forest Inventories (1986–96 and 1997–2007). We then simulated distributional changes between the years 2000–2100. * Without climate change, 9 of the 10 species substantially increased in regional frequency. These increases occurred primarily within current ranges, although some species also expanded across their range edges. With climate change, one temperate conifer species and two sub-Mediterranean species would reduce their frequency of occurrence across the studied region, whereas temperate broad-leaved species were unaffected and Mediterranean species were either unaffected or increased their frequency of occurrence. * Synthesis. The analysis suggests that these species are substantially out of equilibrium, such that abundances and ranges would increase without climate change. Climate change may increase, decrease, stabilize or shift distributions, in a way that can only be understood by comparing predictions against baseline scenarios that account for these non-equilibrium range dynamics.</style></abstract></record></records></xml>