Leaf litter ant (Hymenoptera: Formicidae) species richness and composition along an urbanized forest edge

The effects of forest edge on ant richness and community structure was examined within an urbanized area of northeast Ohio. Leaf litter ant faunas were inventoried in three deciduous forest fragments that have resulted from human disturbance. Each differed in their size and proximity to the urban core. Within each fragment surveys involved leaf litter extraction and sucrose solution baiting along a 150m transect. We collected 4670 ants, belonging to 14 genera and 29 species. Edge samples accumulated more species and at a higher rate than samples located in the forest interior. Sample-based rarefaction revealed increased, but not significantly, species richness and species density along the forest edge. The higher ant diversity along the edge can be explained by the intrusion of open area species able to penetrate the boundary between the two habitats. Edges appear as potential stepping stones for ant colonization of forest remnants. Although most of the common and abundant ant species were equally recorded at the edge and the forest interior, others changed in their relative abundance and frequency of occurrence along the edge. The latter, combined with the presence of “edge” species resulted in a different community structure between the edge and the forest interior, as confirmed by the greater species overlap along the edge compared to the forest core. Small remnants appear more easily colonized, as evidenced by the finding of open area species deeper into their core, and the more homogeneous species makeup compared to that of large fragments.