Processes involved in species saturation of ground-dwelling ant communities (Hymenoptera, Formicidae)

The species saturation hypothesis in ground-dwelling ant communities was te sted, the relationship between local and regional species richness was stud ied and the possible processes involved in this relationship were evaluated in the present paper. To describe the relationship between local and regio nal species richness, the ground-dwelling ant fauna of 10 forest remnants w as sampled, using 10 l m(2) quadrats in each remnant. The ants were extract ed from the litter by using Winkler sacs. Using regression analyses, an asy mptotic pattern between local and regional species richness was detected. T his saturated pattern may be related to three processes: (i) high interspec ific competition; (ii) habitat species specialization; or (iii) stochastic equilibrium. It is concluded that non-interactive processes, such as stocha stic equilibrium and habitat specialization may act as factors regulating s pecies richness in this community. The predominance of locally restricted s pecies, in all sampled remnants, seems to indicate the occurrence of a high degree of habitat specialization by the ant species. This result is eviden ce for the hypothesis that community saturation has been generated by non-i nteractive processes. Although ants are frequently described as highly inte ractive, it is possible that interspecific competition is not important in the structuring of ground-dwelling ant communities.