Spatial aspects of gardens drive ranging in urban foxes (Vulpes vulpes): the resource dispersion hypothesis revisited

Red foxes are a well-established species of urban ecosystems in the UK and worldwide. Understanding the spatial ecology of foxes in urban landscapes is important for enhancement of urban biodiversity and effective disease management. The Resource Dispersion Hypothesis (RDH) holds that territory (home range) size is linked to distribution and richness of habitat patches such that aggregation of rich resources should be negatively associated with range size. Here we tested the RDH on a sample of 20 red foxes (Vulpes vulpes) in the city of Brighton and Hove. We focused on residential garden areas as foxes were associated with these in previous studies. We equipped 12 male and 8 female foxes with GPS collars recording at 15 - minute intervals during discrete seasons over four years. We regressed fox core area size against garden size, number of garden patches and edge density within and between patches as extracted from GIS, in a series of bivariate linear mixed models. We found that foxes used smaller core areas where gardens were large and well-connected, and larger core areas where numerous, smaller gardens were fragmented by internal barriers (e.g. fences, walls) or bisected by other habitats such as managed grassland or built-up areas. Our findings confirm the RDH and help to inform future urban planning for wildlife.