The Effects of Treefall Gap Disturbances on Litter Ant Assemblages in a Tropical Montane Cloud Forest

In this study, we considered the effects of treefall gap disturbances on leaf litter ant assemblages in a Neotropical montane cloud forest. We asked a series of questions: (1) Do species richness, number of workers, and assemblage composition of leaf litter ants differ between treefall gaps and adjacent intact forests? (2) Do leaf litter ant assemblages become more similar to the assemblages in adjacent forest as gaps age? (3) What abiotic and biotic factors are correlated with ant species richness, and does the relative importance of these factors differ between gap and intact forest sites? To address these questions we sampled leaf litter ant assemblages and estimated a suite of abiotic parameters in 12 large (> 80-m²) treefall gaps across a chronosequence and in 12 paired adjacent intact forest sites in the Monteverde Cloud Forest Preserve in Costa Rica. Estimated species richness was higher in gap sites than in intact forest sites, but worker abundance and assemblage composition did not differ significantly between habitats. Ant assemblages in gap sites did not become more similar to those in adjacent intact sites as gaps aged. Our study demonstrates that ant assemblages in the Monteverde Cloud Forest Preserve are weakly affected by the formation of treefall gaps. However, variation in local assemblage structure appears to be influenced by landscape-level processes, which operate at larger spatial scales than those occurring between treefall gaps and intact forest sites.