Forest edge effects on termites in a neotropical rainforest

Termites are dominant arthropods in tropical forests, where they play a major role in organic matter decomposition. However, their activity may be reduced by habitat degradation, to which soil-dwelling species are especially sensitive. Nowadays, one of the major threats affecting tropical forests is fragmentation, through two concurring effects: a reduction in area of the forested zones, and an increase in the length of forest edges. These effects are hard to disentangle. In this study, we took advantage of a powerline clearing to evaluate edge effects on the termite fauna of an otherwise continuous rainforest in French Guiana. No edge effect was detected 100--300 m into the interior. Soil feeders were not significantly less present at the forest edge although they have an allegedly thinner skeleton and a need for moist and soft soil. Finally, no increase in beta diversity near the edge was found either. Overall, it seems that termites are resilient insects against forest edges as long as the fragment size stays large enough. However, a 3-fold larger presence of an opportunistic and pest species (Heterotermes tenuis) was found at the forest edge. We hypothesize that H. tenuis good adaptability and dispersibility may have allowed it to quickly colonize and dominate this new environment before more cryptic species, as it has been shown for ants.