Formation- and Species-Level Responses of the Atlantic Forest to Climate Change

The hyper-diverse Atlantic Rainforest on the eastern coast of South America comprises deciduous, semideciduous, and evergreen forest formations. How these formations, both as communities and through their individual species, are responding to climate change remains elusive. Using habitat suitability modeling, we examine the effects of climate change on the distribution of the Atlantic Rainforest assessed both at the species level and the formation level. Additionally, we investigated whether mismatches between species- and formation-level trends are linked to the climatic affinities of species at the formations where they occur. We predicted a decrease in habitat suitability for all deciduous, semideciduous, and evergreen formations, based on individual species models, up to 2100. However, when considering species together as formations, we predicted expansions of deciduous and semideciduous formations and contractions of evergreen formations for the same period. The divergence between the synchronous and individual suitability models for deciduous and semideciduous formations suggests that climate-tolerant species will likely expand their range, replacing those with narrower climate tolerances. This shift may alter the structure and composition of these communities as currently known. Our findings provide valuable insights that can inform strategies for conserving the Atlantic Rainforest, including the development of new regulatory measures, the establishment of protected areas, and the formulation of effective forest management policies.