Do different relevance attributes indicate the same conservation priorities? A case study in caves of southeastern Brazil

In the last decade, the scientific community brought to the debate gaps that slow down the advance of knowledge regarding global biodiversity. More recently, this discussion has reached subterranean environments, where these gaps are even more dramatic due to the relict and vulnerable nature of their species. In this context, we tested ecological metrics related to some of these gaps, checking if the biological relevance of the caves would change depending on ecological attributes related to each metric. The study was carried out in caves from southeastern Brazil, located in a region presenting a high richness of troglobitic species restricted to a narrow geographical extent. Thus, we verified: (a) the cave invertebrate communities’ vulnerability with the Vulnerability Index and the Importance Value for Cave Conservation; (b) the distribution and endemicity of the troglobitic species with the Endemicity Index; (c) the phylogenetic diversity of the troglobitic species considering the average taxonomic distinction (∆+), their richness and evenness. We observed a considerable change in the ordering of the caves’ biological relevance according to each tested attribute (index). We discussed how each of these metrics and their attributes indirectly relate to: (a) the preservation and maintenance of the phylogenetic diversity of subterranean communities; (b) the spatial restrictions of different groups, where the greater their restrictions, the greater their vulnerability; (c) the preservation of caves with high biological relevance considering these different attributes together. Thus, we recommend the use of different metrics so that different ecological attributes can be considered, supporting actions that aim to preserve caves in highly altered regions. Finally, we find that the most biologically important cave in the region is not protected (Gruta da Morena cave). We warn that this cave needs to be contemplated by a conservation unit in the region urgently.