Effects of agricultural land use and climate change on abundance and demography differ between two common small mammal species

Changes in land use and climate can have important consequences for natural environments, operating as multilevel processes affecting population dynamics, demography and spatial activity of small mammals, potentially leading to cascading ecosystems effects. In a large-scale replicated field study, the response of small mammals to two climate conditions (ambient versus temperature and precipitation expected for the end of the century) and five land use types (conventional farming, organic farming, intensive meadow, extensive meadow and extensive pasture) was studied. For two years, small mammals were live-trapped monthly throughout the breeding season in open plots, individually marked and species, body measures, sex and reproductive status recorded. Common voles (Microtus arvalis; 74%) and wood mice (Apodemus sylvaticus; 22%) dominated. The effects of climate manipulation were sparse, restricted to 14% higher residency in common voles in autumn and more than doubling abundance of wood mice in spring and summer. Common voles seasonally preferred (extensive) land use with little disturbance (at least doubling abundance and increasing residency 39-128%). Seasonally, reproductive activity in common voles was twice as high in grassland than in croplands but in wood mice 5.2-9.5-fold higher in conventional farming than in extensive meadow and organic farming. Common voles were clearly affected by land use while in wood mice climate seemed to matter more. Habitat effects seemed to override climate effects in common voles indicating only marginal changes in habitat use at future climate conditions. However, seasonally there could be larger resident populations of common voles and higher wood mouse abundance that may cause damage in agriculture and/or forestry, affect food webs and pathogen transmission patterns.