Arthropod community composition in urban landscapes is shaped by both environmental filtering and dispersal limitation

Abstract

We assessed the relative importance of environmental filtering and dispersal limitation in structuring foliage- and ground-dwelling arthropod communities in central North Carolina. We hypothesized that both the local environment and the dispersal distance between sites would predict community composition, but that dispersal distance would be more important for ground arthropods than for foliage arthropods. In both groups, variation in habitat characteristics was important in structuring communities, and the role of dispersal in structuring communities was much greater after accounting for variation in landscape connectivity. Our results demonstrate the importance of both dispersal limitation and environmental filtering in shaping community composition and emphasize the importance of variation in the landscape for modeling these forces. Examining communities of multiple arthropod groups across the same spatial gradient highlights the scale-dependence of these processes and illustrates how variation in the environment can alter the relative abundance of specialist and generalist taxa.