Species persistence and climatic stability have shaped plant communities of the Atlantic forest biodiversity hotspot

BackgroundThe remarkable floristic diversity of the Atlantic Forest is partly related to the diversity of environmental conditions across its vast geographic extent that has resulted in distinct plant communities. Four areas (Pernambuco, Bahia and Northern Esp & iacute;rito Santo, S & atilde;o Paulo, and Araguaia-Tocantins refugia) have been hypothesised to have particularly high modern diversity due to their being located in areas of multi-millennial climate stability.AimsTo test if species persistence and climatic stability over the last 21,000 years can predict hypothesised refugia in the Atlantic Forest domain.MethodsWe modelled the distributions of 282 tree species from various habitats and projected them using eight past climate scenarios in the last c. 21000 years. Based on the spatial overlaps among these projections, we inferred three types of refugia: species persistence refugium based on probability of occurrence, climatic stability refugium based on climate suitability and bioclimatic refugium based on the intersection of the previous two. We validated model projections with fossil pollen data.ResultsWe identified five potential bioclimatic refugia (Bahia and Northern Esp & iacute;rito Santo, S & atilde;o Paulo, Parana & iacute;ba, Serra do Espinha & ccedil;o and Subtropical Serra do Mar) and one climatic stability refugium (Pernambuco).ConclusionsWe validated three of four previously hypothesised refugia and detected two additional ones by considering both species persistence and climatic stability as key determinants of refugia. Conservation policies are needed to protect areas of refugia in the Brazilian Atlantic Forest, named: (1) Pernambuco bioclimatic refugium, (2) Bahia and Northern Esp & iacute;rito Santo bioclimatic refugium, (3) S & atilde;o Paulo bioclimatic refugium, (4) Paranaiba bioclimatic refugium, (5) Serra do Espinha & ccedil;o bioclimatic refugium and (6) Subtropical Serra do Mar bioclimatic refugium;Financing studies with focus in determining refugia extension and understanding the region's dynamics is key to promote the sustainability of ecosystem services in face of climate change;Promoting restoration strategies in regions considered as refugia can help sustain habitats.