Conservação e manejo da diversidade de invertebrados em cavidades artificiais

Abstract

Artificial cavities, despite of having a different genesis (by anthropic activities), are also hipogean environments and can present environmental characteristics similar to those found in caves such as absence of light, more stable temperature comparing to external ones, beyond high humidity and oligotrophic tendencies. In Minas Gerais state the presence of artificial cavities is common due to the mining activities developed since 18th century. These cavities represent shelters for some animal groups. Therefore this work aimed to evaluate their use and invertebrate diversity in artificial cavities, also suggesting a use of these systems as elements in the planning of management actions in natural cavities and/or mining extraction areas and touristic cavities. In this study physical, trophic and biological characteristics and anthropic changes observed in these cavities were evaluated. Invertebrates were collected manually, in 110 artificial cavities distributed in 12 municipalities of Minas Gerais by active search and sketch ploting. Parameters like richness, ecological complexity, species dominance, diversity and similarity were related to the present impacts at epigean environment and to characteristics of hipogean environment (e.g. linear extension, photic zone percentage and geographic distance). In order to evaluate tourism effects under artificial cavities, environmental (temperature and humidity) and biological parameters (composition and structure of invertebrate communities) were observed and monitored previously and posteriorly to anthropic activities in the systems. A total of 594 invertebrate species were found. Trails, deforestation and extractive activities were the most observed impacts. Species richness and biological complexity were lower in artificial cavities than in natural ones. Higher differences of species composition were observed in farther systems. In touristic systems invertebrates tend to search for shelter more in adjacent zones than in those used as touristic route. The presence of artificial lighting and people passing on artificial cavities change temperature and humidity, besides modifying available access to resources to the hypogean invertebrate fauna. Underground artificial systems are important sites for establishment of experiments that can improve management actions applied on caves. The great diversity of species found in underground artificial systems, mainly ombrophilous invertebrates, demonstrate the potential of these habitats as sites that can improve and maintain species richness in sites where natural vegetation was removed.