Impact of landscape and habitat diversity on the diversity of diets of two omnivorous carnivores

The impact of landscape and habitat diversity on diets of invasive and native species is an important issue when planning management or conservation of wildlife. The aim of the present study was to examine the impact of the environment on the diets of invasive raccoon dogs Nyctereutes procyonoides and native badgers Meles meles in two spatial scales in southern Finland. We studied the relationship between habitat diversity and diet in several study areas in southern Finland (landscape scale) and the relationship between diet and different habitat patches around latrine sites in one study area (local scale). Diets of both species differed between the study areas. The higher was the diversity of habitats in the landscape, the higher was the diversity of diet. Diversity of diet of omnivorous carnivores may thus be used as an indicator of habitat diversity. Also, the higher was the proportion of gardens, the higher was the diversity of raccoon dog diet. Raccoon dog diet was in all areas more diverse than badger diet. Overlap of diets was the smallest in the most diverse area and highest in a managed area with fields and industrial forests. In local scale, positive relationships between habitat types and raccoon dog diet included those between birds and gardens, small mammals and spruce forest and meadows, and frogs and gardens and deciduous forests. The models for badgers included those between birds and reed beds, frogs and deciduous forests, and cereal and earthworms and fields.