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iForest -Biogeosciences and Forestry
IntroductionFire is recognized as the most important natural disturbance in Mediterranean ecosystems (Trabaud 1994, Whelan 1995. In the Mediterranean basin, given the long historical human impact on ecosystems, the incidence of fire has always been particularly high (Le Houérou 1987, Trabaud 1987a. In addition to natural causes of ignition, burning was one of the management tools commonly used by man (Naveh 1975, Lloret & Marí 2001. Fire thus acted as a fundamental factor on ecosystem functioning and as a major ecological driver of vegetation changes (Attiwill 1994, Moreno & Oechel 1994, Lavorel et al. 1998, by modeling landscapes (Gillson 2009) and contributing to maintain habitat heterogeneity and biological diversity (Moreira et al. 2001, Blondel et al. 2010.Even though fires have been a major factor in Mediterranean ecosystems for millennia, the general trend in number of fires and area burned in European Mediterranean areas has dramatically increased during the last decades, principally due to land-use and climatic changes (Piñol et al. 1998, Lloret & Marí 2001, Mouillot et al. 2002, González & Pukkala 2007, Pausas & Fernández-Muñoz 2012. According to the predicted climate change scenarios for the Mediterranean region, further increases in wildfire frequency and burned areas are expected (Carvalho et al. 2008, Good et al. 2008.Although Mediterranean vegetation is able to cope with fire (Trabaud 1987a, Pausas 1999a, alterations in the fire regime (in terms for instance of higher fire recurrence or incidence of large events) can generate important consequences for Mediterranean ecosystems (Zedler et al. 1983, Vázquez & Moreno 2001 and their plant diversity. Given the very strong effect of fire on vegetation, plant distribution and ecosystem function could likely be more heavily affected by the ongoing modifications in fire regime consequent to global changes than by the direct effect of climate changes (Pausas & Fernández-Muñoz 2012). Moreover, the combined impact of these fire regime changes and enlarged environmental limitations for post-fire tree recruitment could deeply affect the species composition of Mediterranean forests (Peñuelas & Filella 2001, Peñuelas et al. 2002, Lloret et al. 2004, 2009.It is well documented that Mediterranean ecosystems recover readily after fire through an autosuccessional process (Hanes 1971, Trabaud 1994) based on efficient regeneration strategies. Post-fire recovery is usually realized by direct regeneration, i.e., the fast recovery of a plant community made up by the same species pool that existed before the disturbance (Rodrigo et al. 2004). Two main plant regeneration strategies conferring resilience to Mediterranean ecosystems are the capacity to resprout after fire (resprouter species), and the stimulation of the recruitment by fire (seeder species -Bond & van Wilgen 1996, Verdú et al. 2007). In several fire-prone communities varying proportions of woody sprouters and seeders are included (Hodgkinson 1998. Fire regime may influenc...