Identifying variables that predict hedgehog presence across urban gradients

By Belinda Kooman

Abstract
This study evaluates the role of urban gradients – such as city layout, impervious surface area and nearby land use characteristics – on behavior of urban hedgehogs. Urban hedgehog numbers have declined since the late 20th century for reasons that remain uncertain, and since the majority of hedgehog populations in western Europe now reside in urban environments, this could be devastating to the species. The animals are difficult to study due to their nocturnal lifestyle and common residence in gardens, which are private property; hence, their interaction with the urban environment remains poorly understood.

To help fill this knowledge gap, this research focuses on data collected from camera traps in approximately a thousand gardens, covering thirty municipalities throughout the Netherlands over the span of several years. The data includes animal observations from a great variety of species, including the European hedgehog and others it interacts with, such as the Eurasian badger, the common weasel, the red fox, and many more. Additionally, each garden has environmental data describing its immediate and surrounding environmental factors, as well as characteristics designating it to one of three urban gradients.

Results indicate that suburban gradients are preferred over urban and rural ones, though not significantly. Supplementary feeding and human litter attracts hedgehogs due to ease of access, but cats are heavy competitors for this resource; areas with a balanced tradeoff between human food leftovers and macroinvertebrate food sources therefore appear to be favored. Trees in the vicinity are important for nesting material, animal houses for shelter, and holes in fences for connectivity. Heavy traffic and train tracks instill stress and deter hedgehogs. Ultimately, local variety within rather than between urban gradients appears to be decisive.