Urbanization affects the behavior of a predator-free ungulate in protected lands

Abstract

Natural habitats have been converted to urban areas across the globe such that many landscapes now represent matrices of developed and protected lands. As urbanization continues to expand, associated pressures on wildlife will increase, including effects on animals in adjacent protected habitats. For prey species (e.g., ungulates), an understanding of the ecological impacts of urbanization is typically confounded by coincident effects from co-occurring predators. Yet, understanding how urbanization affects prey behaviors in the absence of predators is becoming increasingly relevant as many top predators face extirpation. We placed camera traps at varying distances from urban areas within protected areas in the Florida Keys, USA, to evaluate the influence of urbanization on the behavior of the key deer (Odocoileus virginianus clavium), an endangered species that has been without non-human mammalian predators for ∼ 4000 years. We predicted that as distance to urban areas decreased, key deer would use sites at the same rate, exhibit bigger group sizes, and shift activity patterns to be more nocturnal. Our results indicate that intensity of site use decreased with proximity to urban areas, potentially reflecting human avoidance. Group size increased closer to urban areas, consistent with other studies relating this behavior to anthropogenic subsidies and vigilance for humans. Activity patterns changed but did not become more nocturnal near urban areas as predicted by global analyses relating human disturbance to wildlife nocturnality. Our results have important implications for ungulate behavioral ecology and, taken together, suggest that influences on protected species from adjacent land uses are an important consideration when planning land use and designing protected areas.