The fox and the beach: Coastal landscape topography and urbanisation predict the distribution of carnivores at the edge of the sea

Abstract

Mitigating the impact of invasive species is a global conservation challenge, which requires an understanding of the factors that drive the distribution, abundance, and ecological interactions of invaders. Red foxes (Vulpes vulpes) are a widespread and abundant invasive omnivore in Australia. They are common in dunes and coastal areas that abut marine shorelines, which provide abundant food resources in the form of carrion. They are considered a key threatening process to Australia's biodiversity. The global literature posits that foxes use a broad mix of habitats, leading to an expectation of few consistent associations of foxes with landscape attributes and human uses of beaches and coastal dunes – this is the fundamental hypothesis tested here. Fox distribution was comprehensively mapped in Eastern Australia (108 km of shoreline, 192 sites, 6900 h of wildlife camera footage) and related (general additive models) to a range of potential drivers (e.g. topographic features, habitat types, urbanisation, connectivity, dogs, fox removal) on ocean beaches. Notwithstanding the catholic nature of red foxes elsewhere, here we show that habitat use by red foxes along ocean beaches is not indiscriminate: more foxes occur on beaches backed by high dunes and large expanses of natural vegetation. Conversely, significantly fewer foxes occur where natural dune habitats have been lost to urban areas. Fox removal did not affect fox distributions. Foxes are functionally important carnivores in coastal landscapes, and their disjunct distribution demonstrated by us suggests a spatially heterogeneous functional signal in coastal food-webs. More broadly, sandy beach ecosystems, interspersed by urban development, dominate many coasts, offering a rich bio-geographic tapestry to test how models of fox habitat choice articulate into invasive species management and food-web interactions.