Winter habitat selection and partitioning in two sympatric farmland small mammals: Apodemus sylvaticus and Mus spretus

Abstract

Patterns of small mammal habitat selection vary according to scale, although there are discrepancies about the importance of macro and micro-scale factors in rodent community assembly. We assess whether differences in their micro and macrohabitat selection patterns explain the coexistence of two sympatric rodents, Mus spretus and Apodemus sylvaticus, in an agricultural area of central Spain. We trapped mice in uncultivated and crop fields using a grid of Sherman traps. Food availability and vegetation structure (microhabitat) and landscape composition variables (macrohabitat) were measured in each plot. We used GLMs to determine the scale predictors related to specific abundance. The importance of each scale in the assemblage was assessed by a variance partitioning procedure. At microhabitat scale, A. sylvaticus was positively related to shrub cover and M. spretus to seed availability. At macrohabitat scale, A. sylvaticus was negatively associated with distance to the nearest tree, whereas M. spretus was positively associated with this variable. Macrohabitat explained 39 % and microhabitat 8 % of the variance in the assemblage. Results suggest a relative segregation of food preferences at microhabitat scale, and a habitat partitioning at macrohabitat scale, which may allow spatial coexistence of both species, according to community assembly theory. This study shows the importance of both micro and macrohabitat in the configuration of rodent assemblages.