Changes in the home range sizes of terrestrial vertebrates in response to urban disturbance: a meta-analysis

Abstract

The unprecedented growth rate in human population and the increasing movement of people to urban areas is causing a rapid increase in urbanisation globally. Urban environments may restrict or affect the behaviour of many animal species. Importantly, urban populations may change their spatial movement, particularly decreasing their home ranges in response to habitat fragmentation, the presence of landscape barriers and the availability and density of resources. Several species-specific studies suggest that urban animals decrease their home ranges compared with their non-urban counterparts; however, it remained unclear whether this pattern is widespread across taxa or is instead restricted to specific taxonomic groups. Consequently, we conducted a meta-analysis, collecting 41 sets of data comparing home ranges in both natural and urban environments in 32 species of reptiles, birds and mammals. We calculated effect sizes as the difference in animal home range sizes between natural and urban environments. We found that the home ranges were smaller in urban environments compared with natural environments (mean effect size = -0.844), and we observed a similar result when considering birds and mammals separately. We also found that home range sizes were not significantly affected when disturbance in urban areas was minimal, which suggests that many species may be able to tolerate low levels of disturbance without changing their movement patterns. Our study thus indicates that increasing levels of urbanisation restrict the spatial movement of species across taxa; this information is relevant for ecological studies of further urban species as well as for the development of management strategies for urban populations.