GLOBAL CHANGES AND THE FUTURE OF THE CAATINGA DRY FOREST: LESSONS FROM ANTS

Despite the remarkable diversity and ecological importance of ants in most terrestrial ecosystems, our understanding of ant communities in the Caatinga dry forest remains limited. This chapter provides a comprehensive synthesis of Caatinga ant communities, emphasizing their biogeographic connections to the Cerrado and their relatively low diversity. It also examines how anthropogenic disturbances—including chronic pressures (e.g., extensive grazing and resource extraction) and acute events (e.g., slash-and-burn agriculture)—as well as climate change, particularly increasing aridity, reshape ant communities and affect ecosystem functions mediated by ants. These disturbances drive changes in ant morphology and behavior, reduce functional and phylogenetic diversity, and often favor generalist and disturbance-adapted species, leading to biotic homogenization. This, in turn, disrupts critical functions such as seed dispersal (mediated by key species like Dinoponera quadriceps) and plant protection against herbivores. Furthermore, aridity can amplify the negative effects of anthropogenic disturbances. However, ground-foraging ant communities exhibit relatively rapid regeneration, driven by increases in plant biomass, and the ecosystem functions they support also recovering quickly. However, the proliferation of leaf-cutting ants (Atta and Acromyrmex spp.) in disturbed areas presents a significant challenge to vegetation regeneration by depleting seed banks, reducing seedling survival, and altering nutrient dynamics. As human activities and climate change continue to intensify, the future of the Caatinga remains uncertain. However, as key ecological players, ants offer important insights into these changes, highlighting both the vulnerabilities and resilience of this dry forest. Their responses to ongoing disturbances provide valuable lessons for biodiversity conservation and ecosystem restoration.