Name: Lino S

Biodeserts supervisor: Santos X

Co-supervisor: Alvares F, Sillero N

Title: The impact of fire on mammal species: a meta-analysis and the particular case of the Iberian wolf (Canis lupus signatus) in Portugal

Institution: University of Porto

Status: Completed

Abstract

Wildfires are a fundamental factor for the functioning of most ecosystems throughout the globe. However, since fire regimes are predicted to immediately respond to climate change, large-scale changes in their frequency, seasonality and severity are expected. These altered fire regimes can greatly affect biodiversity and ecosystem functioning. Thus, knowing how fire impacts plant and animal communities is a subject of great interest for biodiversity conservation and management. Several studies have addressed this subject, for most animal groups, but there is still a great lack of information. Concerning mammals in particular, few studies have addressed fires’ effect on large carnivores, leaving a great gap of knowledge in relation to other trophic levels. This study aimed to analyse the effect of fires on mammal species by focusing on several scales. First, by means of a qualitative meta-analysis based on literature review, we evaluated patterns of response to fire on mammals in relation to biological traits and eco-geographical variables. A log-linear analysis showed that the variables that fitted the model did not interact with “Response to fire”, thus failing to illustrate any significant pattern. In conclusion, our results suggest that mammal’s responses to fire are complex and depend on inherent species traits, rather than on global patterns or environmental characteristics. Furthermore, it was possible to confirm that there is a great lack of studies concerning fires’ effect on large carnivores. We highlight the need for studies focusing on population trends and responses of large carnivores to fire disturbance. Thus, as second analysis, this study also evaluated fires’ effect on a large carnivore, the Iberian wolf (Canis lupus signatus), at both regional and local levels. At regional level, focused on the effects of fires on wolf range patterns, we analysed areas of wolf persistence and extinction in Portugal, considering available presence data from 1980 and 2003, in relation to variables related to fire-history, elevation and land cover. We conducted a t-test, followed by a logistic regression in which «Persistence» and «Extinction» were used as dependent binary variable. Results showed that wolf populations persisted in relatively more elevated and steeper areas, with less forest cover and more shrublands. Concerning fire patterns, wolf populations persisted in areas of high fire incidence (more than 263 000 hectares burned) mostly affected by recurrent medium (occurring every year) and large fires (occurring every four years). At local level, focused on the effects of fires on breeding patterns of wolf packs, we evaluated the effect of fire-history, elevation and land cover variables on breeding-site selection (in relation to the remain pack territory) and breeding-site use, by considering consecutive years of reproduction. To determine variables related to breeding-site selection we used the Wilcoxon’s matched-pairs test, comparing ecogeographic variables between 500 and 7000 meters radius circular buffers around each breeding site. Furthermore, we evaluated wolf behavioural response to fire in terms of breeding-site reuse, a year after fire disturbance, using a Generalized Linear Mixed Model. Results showed that reproductive cores of the breeding-sites (500m buffer) were located in extensive natural areas, at a higher altitude than the remaining pack territory (7000m buffer), but were also subjected to a higher proportion of burnt areas (a mean of 90 hectares burned). Results also showed that the packs reused their breeding-sites in consecutive years, in a similar proportion whether or not a fire event had occurred the year before. In conclusion, results suggest that wolves show a high resilience to fire, as fire events do not seem to have a major role in shaping Iberian wolf occurrence and breeding-site selection and reuse. Wolf populations in Portugal persist and reproduce in highly fire-prone areas, leading to changes in vegetation cover and refuge conditions that may promote behavioral responses and potential negative effects, especially in human-dominated landscapes, where wolves are heavily persecuted.