Landscape evolution in ferruginous geosystems of the Iron Quadrangle, Brazil: a speleological approach in a biodiversity hotspot

Abstract

Natural subterranean caves represent a complex system, and studying them requires a holistic perspective considering their integration with the landscape. The vegetal cover around caves plays a key role in the energy input to the subterranean environment, mainly in caves associated with ferriferous formations, since the primary production by photosynthetic organisms is absent in such environments due to the permanent darkness. The current research aimed to characterize transitions in the composition of the surrounding landscape of a set of 235 ferruginous caves in the Iron Quadrangle, (Minas Gerais, Brazil) from 1984 to 2015, using information of remote sensors, geoprocessing techniques and concepts of landscape ecology. The analysis of landscape composition indicated a significant decrease in the conservation level of the study area (530 km2), which has lost 22.14% of the original vegetal cover. The conversion of native vegetation into anthropized areas in this period eliminated almost the entire protection radius of 15% of the caves known in the region, as well as committed the surrounding area of other 32%. This study demonstrated the need to develop scientific researches that relate the cave fauna and vegetal cover surrounding the caves, as well as the consequences that anthropic activities may cause to the subterranean environment.