Multiple Factors at Regional, Landscape, and Local Scales Determine Spider Assemblage Composition in Pomegranate Orchards

Abstract

Orchards may support high spider diversity relative to annual crops due to their structural complexity and relative stability. Multiple environmental conditions at the landscape, regional, and local scales may influence the assemblage composition of spiders in orchards. We asked which environmental variables best explains spider assemblage composition and the similarity of the assemblages of pomegranate orchards located along a latitudinal gradient in Israel? Spiders were sampled from twelve pomegranate orchards along a climatic gradient from north to south. Orchards located at higher latitudes had richer assemblages than orchards located at lower latitudes. The assemblage composition was influenced at the large scale by latitude and annual crop cover in the surrounding landscape but not by local factors. By contrast, functional groups based on foraging strategies were affected by local scale factors, such as vegetation within the orchards. This study demonstrates the importance of considering environmental variables at different scales to understand the factors affecting the assemblage composition of naturally occurring predators in the orchard.