Cave lithology effect on subterranean biodiversity: a case study in quartzite and granitoid caves

Abstract

Physical features and lithology variations contribute to promoting changes in faunal composition and richness between caves in Neotropics. Cave lithology effects on biodiversity were reported to iron ore caves in Brazil, however, it is less clear to granitoid and quartzite caves. Hence, based on these two kinds of rocks we correlate invertebrates species richness and composition with some cave features (lithology, the distance between caves, cave extension, number of entrances, entrance size, environmental stability, and altitude). Overall, 1,027 invertebrate species were recorded in 50 sampled caves. From this total, 11 obligate cave species were found. Invertebrate assemblages showed considerable turnover between caves and rock types with a strong contribution of replacement component of beta diversity. Replacement influence was greatest in quartzite caves mainly because of altitude and distance among caves. Furthermore, richness was determined by cave extension in both lithotypes, although this relationship was much more pronounced for the granitoid caves, which contradicts previous studies. The granitoid caves studied here are predominantly structured by stacked blocks with macro and meso anastomosed subterranean spaces that provide an extensive network of interstices with structural characteristics similar to shallow subterranean habitats that may increase in habitat availability and species richness. The study highlight that the lithology-mediated effects of cave extension on richness must be considered for quartzite and granitoid in the ecological and conservational proposal. Furthermore, altitude and distance among caves were important elements determining invertebrate composition.