Carbon-diversity hotspots and their owners in Brazilian southeastern Savanna, Atlantic Forest and Semi-Arid Woodland domains

Tropical vegetation provides a myriad of ecosystem services and at the same time is highly threatened. This creates a demand for more efficient conservation strategies that focus on multiple benefits at once. For instance, conservation actions that deliver returns for both aboveground carbon (AGC) and tree species diversity (TSD) would be an advance when compared to carbon-focused initiatives. Here we address this issue by identifying AGC-TSD hotspots in Savanna, Atlantic Forest and Semi-Arid Woodland vegetation domains in southeast Brazil. We modelled Fisher's alpha as an indicator of TSD, using remote sensing, climate and terrain-related data to train the random forests algorithm. We thus defined, mapped and characterized the areas that deliver returns for both AGC and TSD (“hotspots”), identifying the hotspots owners (whether within public or private lands). Our results suggest that among the group of predictor variables, precipitation, valley depth, Normalized Difference Vegetation Index (NDVI) and tree cover percent, are the main indicators of diversity across the state. The spatial patterns of carbon and diversity roughly coincide and indicate that Atlantic Forest has higher values for both indicators. AGC and TSD are weak related, so there is a potential risk for biodiversity if only a carbon-focused conservation approaches are considered across the studied domains. We estimate that 61% of the hotspots are located in unprotected areas within private properties making them highly susceptible to loss. Together, these hotspots account for 6,131,453 Mg of AGC and show mean values of Fisheŕs alpha of approximately 26. Our study reinforces the need to select natural areas on private lands to be considered as priority areas for protection.