Space Use of an Expanding Generalist Predator Is Shaped by Human, Marine and Seasonal Effects on Arctic Tundra.

Generalist species that benefit from human impacts on terrestrial ecosystems and expand their distribution range can threaten biodiversity by outcompeting or predating on native specialists. This is exemplified by the northward expansion of the red fox onto the arctic tundra where this mesopredator threatens endemic arctic fox and ground-nesting bird populations. Here, effective management efforts to control the expansion depend on understanding the spatiotemporal scales of red fox movement within the tundra, and on identifying habitats that provide food resources to red foxes. We addressed these needs by studying the geographic space use and habitat selection of 14 red foxes on the low Arctic tundra of Varanger Peninsula in Norway by means of GPS telemetry. Red foxes used large home ranges and were especially mobile during winter, partly owing to occasional movements beyond home range boundaries. Home ranges were significantly smaller near the marine coastline and at higher human land use intensities, likely owing to higher food availability. These habitat features were also selected for within individual home ranges, confirming the importance of these habitats to red foxes on the tundra. High mobility necessitates large-scale culling efforts aimed at achieving long-term reductions in red fox densities. However, localised and temporary effects may be achieved by aligning culling with periods of reduced red fox movement and breeding of vulnerable species in late spring and summer. Additionally, reducing food subsidies associated with human land use could mitigate the underlying drivers of red fox expansion, offering a more sustainable approach to management.