Anthropogenic disturbance changes the structure of arboreal tropical ant communities

We investigated the influence of anthropogenic disturbance on the structure of arboreal Formicidae communities in SE Asian lowland forests. Included w ere a primary forest and three disturbed forests which had been cut for cro p planting and abandoned 5, 15, and 40 yr after agricultural use for natura l regeneration. Ant communities of at least 10 individuals of one tree spec ies were sampled from each forest type by fogging. Diversity and community structure differed clearly among forest types. During the course of forest regeneration ant communities became more and more similar to those of the p rimary forest. A surrogate analysis shows that ant communities of the prima ry forest cannot be distinguished from randomly composed communities. This is in contrast to the theoretical expectations according to which ant commu nities should be structured by interspecific competition that lead to a lar ge degree of predictability. However, a deterministic pattern of ant commun ities is found in the disturbed forest. This indicates that human disturban ce not only changes the faunistic composition of ant communities but could also change the dynamics of the whole system. The transition from stochasti c to deterministic communities might be of general importance for understan ding the mechanisms structuring communities in disturbed habitats.