Conserving biogeographical units of endemic amphibians in the megadiverse Atlantic Forest

The initial step in many biogeography approaches involves identifying biogeographical units, which serve as fundamental building blocks for understanding biodiversity patterns and guiding conservation efforts. We aimed to analyse the conservation of biogeographical units of an endangered biodiversity hotspot by: (i) detecting clusters of endemic frog species; (ii) testing predictions of vicariance model; (iii) evaluating the conservation of the patterns based on protected areas and habitat loss; and (iv) highlighting priority biogeographical units for conservation. Biogeographical units were identified via Biotic Elements analysis, using range polygons for 381 endemic frogs. We tested two predictions of vicariance model: (i) the occurrence of non-random patterns, forming clusters of co-occurring species (Biotic Elements, BEs); and (ii) the occurrence of closely related species in distinct BEs. We calculated the percentage of forest remnants in each BE and their overlap with protected areas. We highlighted those with high degrees of irreplaceability and/or vulnerability as priority BEs for conservation. We recovered 21 Biotic Elements. Both predictions of the vicariance model were validated. On average, BEs presented 28% of forest remnants, but only 12% of their total areas were protected. Mountain ranges of central Atlantic Forest harbour most of BEs, emphasizing the importance of safeguarding these regions.