Caves’ environmental stability shaping subterranean biodiversity in the neotropics

Abstract

Caves, once thought to be isolated ecosystems", are now understood to have intricate connections with surface environments, particularly evident at their entrances. These connections can significantly affect the microclimate within caves, leading to varying degrees of environmental stability. Our research explores the impact of microclimate conditions, specifically related to cave environmental stability, on biodiversity changes. We surveyed subterranean invertebrates during two different seasonal periods in 17 limestone caves in three karst regions in southeastern Brazil. Our analysis aimed to understand how environmental stability influences the overall richness of cave invertebrates and troglobitic species richness (restricted to subterranean habitats). We hypothesized that more stable caves would experience less fluctuation in relative species richness and lower turnover between seasons. Additionally, we anticipated that caves with greater environmental stability would harbor a higher richness of cave-restricted species in the function of their length. Our findings support these hypotheses, revealing a significant positive correlation between cave environmental stability and species richness. Caves with higher environmental stability demonstrated lower species turnover rates between seasons, indicating enhanced community stability. While environmental stability significantly affected species richness, its influence on cave-restricted species was comparatively less pronounced. This suggests a complex interplay of factors shaping the unique fauna of caves. Nonetheless, the implications of climate change underscore the importance of preserving the environmental stability of these ecosystems. Using environmental stability as a guide can help protect cave biodiversity from the adverse effects of climate change, contributing to broader conservation efforts for these unique habitats.