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Factors influencing the distribution of the lusitanian and the mediterranean pine voles (Microtus lusitanicus and M. duodecimcostatus) in Portugal:a multiscale approach
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Resumo(s)
The main goal of this thesis was to determine the environmental factors influencingthe distribution of two closely related voles in Portugal. More specifically the aimwas to analyse and compare the environmental preferences of the Lusitanian pinevole (Microtus lusitanicus (Gerbe, 1879)) and the Mediterranean pine vole (Microtusduodecimcostatus Sélys-Longchamps, 1839), at different scales of analysis, andalso to quantify the importance of spatial autocorrelation component in speciesdistribution models.At a national level the distribution pattern of pine voles was associated with climatevariables, landscape units, and soil types. The environmental associations at alandscape scale reflected the importance of habitat connectivity and heterogeneityfor the Lusitanian pine vole, and of open areas, free of shrubs, for theMediterranean pine vole. At a local scale, the high importance of verges, especiallyfor the Lusitanian pine vole, highlights the several advantages of these particularvegetation structures for small mammals.The sympatric area of both pine voles was consistently narrow in national andregional distribution maps. Results indicated that the local coexistence of the twovoles should be a rare event.Vole distribution data were characterized by strong spatial autocorrelation evenafter accounting for several significant environmental effects. At the largest scalethe spatial effects were the most important. At a finer scale, these effects, althoughstill important, played a secondary role when explaining the species distributionsand segregation.Furthermore, novel information was provided on space use, social behaviour,activity patterns, and habitat selection of Lusitanian pine vole.The discrimination of the two species in the field, and in a potential sympatric area,was possible using presence signs, namely the proportion of burrow openings.Multiple factors may influence the distribution of pine voles in Portugal. Some ofthese factors gain importance at specific spatial scales and others can only bediscussed using more than one scale approach.
Descrição
Tese de doutoramento, Biologia (Ecologia), 2010, Universidade de Lisboa, Faculdade de Ciências
Palavras-chave
Rato cego Modelos de distribuição Utilização do espaço Ecossistemas Teses de doutoramento