Seasonal variation of ground and arboreal ants in forest fragments in the highly-threatened Cerrado-Amazon transition

An understanding of the spatiotemporal patterns of species distribution is a major goal in community ecology. This understanding is particularly challenging for highly seasonal and diverse habitats, such as transition zones between major biomes, like the Cerrado-Amazon transition (CAT). Within the CAT, there are many kinds of vegetation, including the ecotonal forests, marked by a high seasonality and floristic elements belonging to both surrounding biomes. Here, our primary goal is to examine the temporal variation of ant communities in ecotonal forest fragments of the CAT. More specifically, we assessed whether arboreal ants and ground-dwelling ants responded differently to seasonality. Thus, we sampled ants in the arboreal and ground strata, across the dry and wet season, in six ecotonal forest fragments in the CAT. We found that the seasonal variation was higher for ground-dwelling than arboreal ant communities, and only ground-dwelling ants differed in species richness between dry and wet seasons. Implications for conservation Our results show that ground-dwelling ant communities are more sensitive to seasonal variation than are arboreal ants. These ants often represent the bulk of ant diversity in tropical forests, and the current climate change scenario can be particularly harmful to them. Therefore, future conservation practices need to give special attention to ground-dwelling ants, especially in the CAT, facing increasing anthropogenic pressure.