EFFECT OF TREEFALL GAPS ON THE PATCHINESS AND SPECIES RICHNESS OF NEOTROPICAL ANT ASSEMBLAGES

Natural formation of treefall gaps plays an integral role in the ecolo gical and evolutionary dynamics of many tropical forests, affecting th e spatiotemporal distribution of plants and the animals that interact with them. This study examines the impact of treefall gaps on the spat ial and temporal patchiness of ant assemblages in a moist lowland fore st in Panama. Using pitfall traps and honey baits, we compared ant ass emblages in five 1 to 2-year-old treefall gaps (ca 100 m(2)) and five adjacent plots (ca 100 m2) in undisturbed forest understory at three d ifferent times of year (late wet season, late dry season, and early we t season). We found little evidence that ant assemblages respond drama tically to the formation of treefall gaps and the differences in habit at qualities they produce. Ant abundance, species richness, species co mposition, and rates of resource discovery did not differ between gaps and forest understory. However, we did find significant differences i n numerical abundance related to forest stratum (ground vs vegetation) and resource type in pitfall traps toil-cockroach vs honey), and sign ificant differences in ant species richness and rates of resource disc overy across seasons. While habitat effects by themselves were never s tatistically significant, habitat and seasonal differences in species richness interacted significantly to produce complex, season-dependent differences among gap and forest habitats. These results suggest that the formation of natural treefall gaps has less of an effect on Neotr opical ant assemblages compared to other groups of organisms (e.g., pl ants, birds) or other causes of patchiness (e.g., ant mosaics, moistur e availability, army ant predation). The results of our study also hav e important implica-tions for the underlying causes of habitat differe nces in the distribution of ant-defended plants.