Small parks in residential neighborhoods as habitats for ground-dwelling beetles, spiders, and ants

In residential landscapes, small neighborhood parks account for a considerable share of urban greenspaces. However, information on their significance for biodiversity conservation is limited. To determine the role of small neighborhood parks as habitat for ground-dwelling arthropods, we evaluated the effects of local and landscape factors on the diversity and traits of carabid beetles, spiders, and ants in small neighborhood parks in Niigata, Japan. Urbanization decreased carabid species richness and abundance, and it altered the species composition of carabids and spiders. The arthropods in urbanized sites were characterized by small-bodied, web-building, highly dispersive spiders, and possibly non-predatory carabids. In contrast, urbanization did not influence any diversity metrics of ants. At the local scale, ground cover, soil moisture, and park border permeability were the major drivers of arthropod diversity. Ground coverage with leaf litter was positively associated with ant occurrence. Soil moisture negatively affected carabid species richness and abundance, whereas it positively affected spider richness. Parks with humid soil conditions favored hunting, low-dispersive spiders. The low permeability of park borders decreased spider richness and altered community structure, which was characterized by highly dispersive, ballooning species. We conclude that small neighborhood parks support numerous species of habitat-generalist arthropods that are adapted to dry and open environments. These parks thus represent an important component of habitat networks in residential landscapes. Managing open environments, protecting litter layers, reducing artificial borders, and retaining other open greenspaces in the surrounding matrix can promote diverse arthropod communities. Such strategies are worth considering during urban planning.