A influência de gradientes ambientais e da radiação ultravioleta sobre comunidades de anuros do extremo sul da Mata Atlântica

Abstract

Amphibians are among the most threatened vertebrate groups on the planet, mainly due to anthropic activity and the side effects of these activities. Thus, in the present work we evaluated how the modification of the landscape affects the communities of anurans in a region that historically undergoes habitat conversion pressure of forest into agricultural landscape. We evaluated how UVA and UVB radiation affects the survival and mortality rates of an endemic species of the Atlantic Forest. We carried laboratory tests replicating daily doses of naturally received ultraviolet radiation , such as the doses simulating the increased incidence of the same. We demonstrated that the increase, even a small, of the radiation on the spawning is able to induce death and mutations in the anurans. In addition, we also evaluated how the anuran communities, in ponds both inside the preserved forest and in the agricultural matrix, are structured, using a nesting analysis and beta diversity partition approaches. In this way, we demonstrate through the community that there is a species substitution along the gradient studied. Within the same gradient, we tested how the functional diversity of the larval stages of the anurans behaves according increase the distance between breeding ponds and the agricultural activity. Thus, we show that although they are in a conservation unit, the larval stages of anurans of the Parque Estadual do Turvo present a low number of functional groups, which endangers the conservation of the present species. We also tested how the functional, taxonomic and phylogenetic diversity of the communities can change in this gradient, analyzing four data matrices, containing functional traits, environmental data, abundance data and a phylogenetic matrix. In this way, we recorded that the loss of species is responsible for the increase of phylogenetic diversity within agricultural matrix, a pattern that does not occur within the preserved forest. The present work shows that even the protected areas suffer the direct and indirect effects of the anthropic activity that occurs in the surroundings, besides, it makes evident that the flexibilization of the environmental laws that are being proposed can cause severe negative impacts on the fauna and the stability ecosystems.