Strategies for cave prospecting and non-troglobitic biodiversity surveys in Brazil

Subterranean environments are distributed across diverse environmental and geographical landscapes. In this study, we assume that cave occurrences areas in Brazil occupy a multidimensional large-scale space and apply a site selection model that integrates environmental and geographical factors to identify distinct locations for speleological studies. Our approach combines these findings with existing knowledge on the distribution of Brazilian caves. The results reveal 45 unique environmental-geographic sites across five biomes and 19 Brazilian states. Our findings show that when both geographical and environmental heterogeneity are considered, the current knowledge of cave distribution in Brazil remains fragmentary, with particularly evident gaps in the Cerrado, Amazon rainforest, and Caatinga Biomes. These deficiencies almost certainly extend to the documentation of subterranean biodiversity. Most of the sites highlighted by the model contain few or no recorded caves in their surroundings, emphasizing the urgent need for systematic prospecting and biodiversity surveys in these underrepresented regions. Moreover, the lack of a publicly accessible, standardized database compiling primary records of cave biodiversity represents a major limitation for large-scale analyses. This shortcoming likely contributes to the repeated documentation of species within a narrow set of geographical and environmental contexts, thereby restricting comprehensive assessments of subterranean biodiversity across Brazil.