Patrones de uso del espacio del topillo nival Chionomys nivalis (Martins, 1842)

Abstract

There can be major intersexual differences among small mammals in their degree of territoriality, giving rise to a great variety of spatial organization systems which manifest at the interspecific and intraspecific levels. At the intraspecies level, this variety is seen not only between populations, but also within single populations whose spatial organization system changes over time according to the local environmental and social conditions. Taking into account such phenotypic flexibility in microtine social organization patterns, our aim was to study spatial patterns among the snow vole Chionomys nivalis (Martins, 1842) in two study colonies, located in the Sierra Nevada (Andalusia) and Peñalara (Madrid), respectively. We used radiotracking techniques to study snow vole home ranges. Animals were monitored in August 2005 in the Sierra Nevada and in August 2006 in Peñalara. Home range estimates were based on a kernel application since it provided the model best fitted to the particular set of snow vole locations. We observed clear spatial segregation of individuals with a varying degree of overlap between their home ranges in both localities. Nevertheless, there were also differences between the two populations which suggest that the space use pattern in the Sierra Nevada is related to poorer habitat resources (e.g. food and mates) than is the case in Peñalara. Finally, we discuss the most probable mating system in Peñalara based on the characteristics of the space use pattern observed.