Spider Community Composition and Structure in a Shrub-Steppe Ecosystem: The Effects of Prey Availability and Shrub Architecture

Habitat structure is cited as an important factor influencing organisms, but few studies investigate whether habitat structure interacts with other environmental variables to affect community dynamics. The purpose of this study was to determine, using field experiments, the importance of prey availability and shrub architecture on a spider community in northern Utah, USA. We were also interested in determining whether surrounding shrub architectures influence spider and prey responses. Our results suggest that spider distribution, abundance, and biodiversity are influenced by shrub architecture. Shrub architecture influenced spiders both directly and indirectly via associated changes in prey availability. Spiders were also directly influenced by prey availability. Further, spider and prey responses were affected by surrounding shrub architectures, but they type of prey present on shrubs of different foliage types varied only when surrounding shrub architectures were also manipulated. Therefore, the importance of shrub architecture depends on the spatial scale to which organisms respond most strongly