Ictiofauna da região da Serra da Canastra, Minas Gerais: cavernas são filtros ambientais considerando-se riqueza, diversidade e comportamento alimentar?

Abstract

The subterranean (or hypogean) environment is formed by interconnected spaces of the subsoil or subsurface filled with water or air and has a marked characteristic of darkness in deeper areas and little variation in abiotic conditions, such as high relative humidity and constant temperature. One of the characteristics observed in many caves and other subterranean habitats is the tendency for food scarcity, where most of the time the supply of food is by allochthon origin, thus influencing the richness and distribution of the fauna. These factors, among others, make the hypogean environment extremely fragile. This study aimed to present historical data for the ichthyofauna in the São Francisco basin and to compare them with data occurring in caves and epigeanl stretches of São Roque de Minas region, Minas Gerais state, in addition to verifying physico-chemical data, richness and diversity. Three collection occasions were carried out using combined methods. Historical data were also used to compare the subterranean ichthyofauna occuring in the São Francisco Basin. The rio São Francisco River basin presented 26 species in hypogean stretches of rivers, eight troglobitic restricted to subterranean habitats, most of which are found in the state of Bahia. For the São Roque de Minas region, 13 species were recorded, seven in hypogean stretches. Concomitantly, the data collected for the region were analyzed aiming at the diversity of the ichthyofauna, verifying similarity of species and degree of health, testing the hypothesis that the caves represent an environmental filter for the local ichthyofauna.