Patch and landscape-scale variables influence the taxonomic and functional composition of beetles in urban greenspaces

Abstract

Urbanization is a leading cause of species extinction; however, interest in urban greenspaces as sites for conservation has grown considerably in recent decades, raising questions about the ability of these habitats to support desired wildlife. Our goal was to determine how distinct forms of urban greenspace and their landscape context influenced the species composition of ground-dwelling beetle communities. We examined the taxonomic and functional composition of Carabidae and Staphylinidae in urban vacant lots, urban farms, and planted urban prairies within the City of Cleveland, Ohio. Beetles were collected using pitfall traps across 23 sites. We found that the three habitats examined varied significantly in beetle composition, with several unique species found within each type of greenspace. Carabidae abundance and richness were greater in urban prairies and urban farms relative to vacant lots. The abundance and taxonomic richness of Staphylinidae were highest within urban farms. Canonical correspondence analysis (CCA) and partial CCA revealed that both local features and landscape variables influenced beetle community assembly. Most beetle taxa were negatively associated with buildings within the surrounding 1-km landscape, whereas grass was the most important local habitat feature. Additionally, we found variation in the distribution of species traits among habitats; ecological traits such as moisture tolerance and dispersal capacity differed significantly among urban greenspaces. Most interesting from a conservation perspective was a greater abundance of brachypterous carabids found in urban prairies, which suggests that these habitats provide overwintering and breeding habitat for some beetle species. Our findings demonstrate that urban greenspaces play important roles in shaping arthropod diversity in cities, and maintaining habitats that vary in design and management is important for their conservation.