Priorities for cave fauna conservation in the Iuiú karst landscape, northeastern Brazil: a threatened spot of troglobitic species diversity

Abstract

The definition of priority for conservation becomes an emergency because habitat loss and degradation are among the main impacts on karst landscapes. In this sense, the present study aimed to evaluate the priorities for cave conservation through the combination of indexes that use species richness, species distribution, and proportion of the deforested area (PDA). The caves presented 287 non-troglobitic species and 37 species (11.7 %) with troglomorphic traits that are distributed in 50 % of the caves. The caves also present a high phylogenetic and functional diversity of terrestrial, aquatic, and amphibious cave-restricted species, including many predators, scavengers, and one phytophagous species, most of them presenting remarkable specialized traits and restrict distribution in a few caves and in specific biotopes. The PDA were positively related to the distance from the limestone outcrop, because of the restrictive landforms for agropastoral activities. At least two caves present extremely high priority for conservation (Baixão and Baixa da Fortuna caves), while four caves present high priority, and almost all others require at least a conservation action. Suggestively, in this specific case, a coherent strategy was shown to maintain the preserved vegetation around the caves, improving the restoration of small fragments and minimizing alterations. Despite the results of the indices, the singularity of the area regarding the taxonomic and functional diversity of troglobites also reinforces the urgent need for conservation actions.