Seasonal, Successional, and Vertical Segregation in a Maryland Ant Community

Ecological segregation was studied in a diverse ant community within the coastal plain province of Maryland, USA. Distributional data were obtained from yearround samples of species associated with the litter and low arboreal strata in three successional sites. Of 52 species which were encountered, 19 occurred commonly enough for quantitative niche analysis. Most local ant species are trophic generalists, but are specialized with respect to major habitat (e.g., old-field vs. forest). Additional differentiation is achieved by vertical segregation of foraging microhabitat and by dispersion of seasonal activity modes. Formal analysis of the components of diversity indicates that the independent contributions of three resource dimensions (successional habitat, vertical microhabitat, and seasonal activity) together account for about half of the observed total community diversity, while within-microhabitat overlap contributes an additional 37%. The remaining 13% of the observed community diversity is due to 2-way and 3-way interactions (i.e., redundancy) among the three resource axes. Niche breadth is shown to be correlated with overall abundance across all habitats, but local abundance within favored habitat-microhabitat combinations is largely independent of niche breadth.