Flora cavernícola: diversidade e ecologia das comunidades vegetais em cavernas

Abstract

Cave ecosystems, with their specific environmental conditions, harbor unique biodiversity characterized by distinctive evolutionary and adaptive traits. Despite their significance, research on cave flora, especially in tropical ecosystems, is scarce. This thesis investigates the ecology of cave flora, focusing on the factors influencing the distribution, richness, and composition of plant communities along the light gradient at cave entrances in a neotropical montane ecosystem. The aim is to understand the ecological patterns of cave-dwelling plants, contributing to closing this knowledge gap and promoting conservation strategies. We conducted sampling at cave entrances in Ibitipoca State Park (PEIB) in Minas Gerais, Brazil, a protected area known for its diverse vegetation and numerous quartzite caves. Using a luxmeter, we defined zones of light up to the dark penumbra region and analyzed vegetation structure, soil and environmental variables. Our results revealed 134 plant species, with angiosperms being the most diverse group in photic zones and bryophytes in dysphotic zones. Species richness decreased with depth, and significant differences in composition were observed among caves, entrances, and light zones. Soil analysis identified key variables influencing plant community structure. Additionally, we deepened our understanding of the bryoflora associated with Brazilian caves, examining how geomorphological features, altitude, and distance between entrances affect bryophyte diversity. In thirteen cave entrances within PEIB, we identified 70 species of bryophytes, including 14 new records for the area. The most common life forms were leafy forms, followed by mat, tuft, and weft forms. Our research highlighted that geographic proximity influenced phylogenetic similarity among bryophyte communities, with larger cave entrances supporting greater diversity. Zeta diversity analysis revealed that rare species drive turnover in communities, emphasizing the importance of caves as genetic reservoirs and potential refuges for rare species. These findings underscore the ecological significance and diversity of cave flora in the Neotropics, highlighting the need for conservation strategies that include subterranean plant communities.