Name: Pinto T
Biodeserts supervisor: Santos X
Co-supervisor: Moreira B, Freitas H
Title: The response of reptile communities to wildfires in the Serra da Estrela Natural Park
Institution: University of Coimbra
There is an increasing recognition that fire is an important component of many ecosystems in the world, essential to understand the ecology and diversity of communities in fire-prone regions. It impacts fauna directly, through mortality, or indirectly by changing habitat structure and resources availability. In recent decades global warming, land abandonment and changes in traditional agricultural activities are driving changes in the frequency and extent of fires. In this context, to know the response of organisms to fire regimes is a conservation priority. Reptiles are a good model group to examine their responses to fire as they are ectothermic, sensible to modifications in habitat attributes such as vegetation structure and canopy closure, have low mobility and dispersal rates, and experience high rates of population declines and extinction. The purpose of this study is to evaluate the effects of fire on reptile assemblages at two geographic scales: at a worldwide scale, where I examined patterns of reptile responses to fire considering the time since fire effect with a meta-analysis methodology (Chapter 1); at a local scale, where I evaluated the effect of wildfires on the reptile communities of the Serra da Estrela Natural Park, namely on the population densities, species richness (Chapters 2) and examined how the trophic ecology and interspecific interactions varied with fire using the Psammodrome lizard as a model species (Chapter 3). For this, I used a set of proper methodologies in order to collect and analyze all the data needed to perform this study (search scientific data for a meta-analysis; transects for reptile surveys followed by vegetation and habitat structure characterization; fecal pellets analysis and network metrics for lizard‟s diet). At a worldwide scale, lizards‟ diversity (richness) but not abundance decreases immediately after fire (<1 year) but recovers quickly to pre-fire levels with increased abundance. Regarding snakes, diversity is not significantly affected by time-since-fire but abundance decreases in the latter stages of the post-fire succession. In Serra da Estrela Natural Park, reptile abundance decreases in the first 5 years of post-fire succession, but increases in the interval between 5-10 years. I also found that Psammodromus algirus is positively related with tree cover, and negatively related with herbaceous cover. Plant diversity is also a relevant parameter for reptiles, since its presence (abundance) is positively related with the diversity of plant species. Relatively to the diet, metrics of the bipartite network for lizards collected in unburned and burned habitats demonstrated that P. algirus presents more selective behaviors in unburned habitats, than in burned ones. I have also found differences between burned and unburned areas as regards availability of prey, being the burned area the one presenting the richest arthropod communities. My results suggest that immediately after fire there is a decrease in species richness but communities recover quickly and reptile abundance increases in early stages of post-fire succession (both globally, and also in Serra da Estrela Natural Park). Although reptiles present a close relation with habitat structure, they seem well adapted to areas with different time since fire and present stable abundances across the post-fire succession. Moreover, they have diet variation and are adapted to consume a large variety of preys when conditions are not suitable. In undisturbed areas, they may present a selective behavior.