How historical and present climat conditions affected the distribution of the mediterranean whter shrew?:a phylogeographical and ecological approach

Tese de doutoramento, Biologia (Biologia Evolutiva), Universidade de Lisboa, Faculdade de Ciências, 2014

The Mediterranean water shrew (Neomys anomalus) is a semi-aquatic species with a wide but fragmented distribution across southern and center Europe and Asia Minor. This species is one of the least studied small mammal species not only of the Portuguese but also of the whole European fauna. As such, it is still unclear what are the major factors determining the fragmentation of the Mediterranean water shrew populations. The present work intended to better understand the influence of climate and other ecological factors on the distribution of the Mediterranean water shrew by following a time-scaled multidisciplinary approach, that included: i) the study of the evolutionary history of the species; ii) the analysis of ecological and behavioural aspects determining its current niche space; and iii) the determination of the effects of future climate changes on the species’ distribution. Two factors were identified as significantly contributing to the current distribution pattern of the Mediterranean water shrew: severe climatic alterations, that were extremely important in the evolutionary history of the species and that are also projected to have a significant impact in its future distribution, and the interspecific competition with a congeneric species, which is one of the main factors regulating the current habitat preferences of the Mediterranean water shrew. The followed multidisciplinary and time-scaled approach provided relevant insights on the ecological factors determining the presence of the Mediterranean water shrew, ultimately defining its geographical distribution. It also highlighted the need to clarify the taxonomic status of the Iberian populations of this species. The detection of a unique genetic lineage in this region makes the reported findings highly relevant from an evolutionary perspective, and extremely significant for its conservation.

Fundação para a Ciência e a Tecnologia (FCT, SFRH/BD/31602/2006); CESAM - Centre for Environmental and Marine Studies