ENVIRONMENTAL AND GEOGRAPHIC FACTORS AFFECTING THE DISTRIBUTION OF SMALL MAMMALS IN AN ISOLATED MEDITERRANEAN MOUNTAIN

The distribution patterns of a small mammal community were studied at Montseny (Catalonia, NE Spain), a high and isolated Mediterranean moun tain that constitutes the southern Limit of mid-European vegetal and a nimal communities. We collected information on 25 localities (119-1140 m a.s.l.) and 16,916 small mammals in total (six Insectivora and ten Rodentia species) provided by the analysis of barn owl Tyto alba pelle ts. The relative abundance of the species was related to geographic (a ltitude, latitude and longitude) and environmental (rainfall and tempe rature) variables to establish patterns of distribution. Rainfall and temperature determined the distribution of most species. the former br ing inversely related to diversity, and being higher in lowland than i n highland communities. This diversity trend is contrary to that found in the Pyrenees, the nearest mountain range. Five species inhabiting Pyrenean highlands are not present in the Montseny, probably due to it s isolation and small area. This mountain range is the southern limit for the range of other five species. The interpretation of stepwise re gression and factorial analysis, and a correlation matrix among specie s, enabled us to delineate three groups of species: those inhabiting p referentially Mediterranean areas (S. etruscus, C. russula, E. quercin us, R. rattus, R. norvegicus, M. musculus, M. spretus, M. duodecimcost atus and R. sapidus). those inhabiting preferentially mid-European one s (T. europaea, S. minutus, S. araneus, A. sylvaticus, C. glareolus an d M. agrestis), and a single species with no clear preferences (N. ano malus).