Fauna terrestre da maior cavidade em granito do Hemisfério Sul, sudeste do Brasil: um habitat negligenciado

Studies focusing cave fauna on granitic caves are relatively rare when compared to carbonatic ones and no one considered replicas in the sampling to test fauna distribution patterns. We describe the terrestrial fauna of Riacho Subterrâneo cave through four sampling occasions (replicas) in different seasons. We analyzed seasonality and substrate preference of terrestrial invertebrates and discussed the importance of this neglected habitat as a refuge for fauna. Furthermore, we stressed the importance of the replicas in order to detect subterranean biodiversity patterns. The cave represents the greatest richness considering igneous rocks in Brazil (199 taxa) and has an important role as refuge for epigean fauna, besides the maintenance of troglophilic and trogloxene populations.Keywords: subterranean microhabitats, igneous rock, Neotropical Region, seasonality, refuge.Estudos com foco em fauna de cavidades graníticas são relativamente raros comparados àqueles em rochas carbonáticas, e nenhum deles considerou a realização de réplicas para teste de padrões de distribuição da fauna. Descrevemos a fauna terrestre da Gruta do Riacho Subterrâneo por meio de quatro ocasiões de amostragem (réplicas) em diferentes estações do ano. Analisamos a influência da sazonalidade e a preferência por substratos da comunidade de invertebrados terrestres e discutimos a importância deste habitat negligenciado como refúgio para a fauna. Ainda, discutimos a importância da realização de réplicas para detectar padrões de biodiversidade subterrânea. A cavidade apresenta a maior riqueza biológica dentre as cavidades em rochas ígneas no Brasil (199 táxons) e desempenha um papel importante como refúgio para fauna epígea, além de manutenção de populações troglófilas e trogloxenas.Palavras-chave: micro-habitats subterrâneos, rocha ígnea, Região Neotropical, sazonalidade, refúgio

Brazilian obligatory subterranean fauna and threats to the hypogean environment

The subterranean environment harbors species that are not capable of establishing populations in the epigean environment, i.e., the obligatory subterranean species. These organisms live in a unique selective regime in permanent darkness and usually low food availability, high air humidity in terrestrial habitats, and low temperature range allied to other unique conditions related to lithologies and past climatic influences. The pressure to increase Brazil’s economic growth relies on agricultural/pastoral industries and exporting of raw materials such as iron, limestone, ethanol, soybean, cotton, and meat, as well as huge reservoir constructions to generate electricity. Mining (even on a small scale), agricultural expansion, and hydroelectric projects are extremely harmful to subterranean biodiversity, via the modification and even destruction of hypogean habitats. The Brazilian subterranean species were analyzed with respect to their distributions, presence on the IUCN Red List, and current and potential threats to hypogean habitats. A map and three lists are presented, one with the described obligatory subterranean species, one with undescribed taxa, and one with the current and potential threats to the hypogean environment. To date, 150 obligatory subterranean species have been recorded in Brazil, plus at least 156 undescribed troglomorphic taxa, totaling 306 Brazilian troglobites/obligatory cave fauna. We also analyzed the current and potential cave threats and the conservation actions that are underway to attempt to compensate for loss of these habitats. In according to the Brazilian legislation (Decree 6640) only caves of maximum relevance are fully protected. One strategy to protect the subterranean fauna of Brazil is the inclusion of these species in the IUCN Red List (one of attributes that determines maximum relevance for caves); however, one of the IUCN assumptions is that the taxa must be formally described. It is clear that the description and proposed protection of Brazilian subterranean biodiversity depends on more systematics studies

Taxonomic distinctness and conservation of a new high biodiversity subterranean area in Brazil

Subterranean environments, even though they do not possess a primary production (photosynthesis), may present high biodiversity, faunistic originality, endemism, phylogenetic isolations and unique ecological and/or evolution events, in addition to rare taxa. Studies investigating the biological diversity in Neotropical caves are relatively rare and recent, and most of them have been conducted in Brazil. We sampled caves from the state of Bahia, northeastern Brazil, and through sampling sufficiency tests and richness estimators, we demonstrate that the normatization for the Brazilian cave laws is not adequate for its conservation and that only α diversity index is not enough to verify faunistic patterns. We suggest that a phylogenetic diversity index be more robust and accurate for conservation purposes, particularly the Taxonomic Distinctness index. Moreover, we propose that the sandstone complex caves from Chapada Diamantina National Park need to be classified as being of high subterranean biodiversity in a global scope