Efeito da qualidade do habitat sobre a estrutura da comunidade de pequenos mamíferos não-voadores no Triângulo Mineiro – MG, Brasil

Abstract

Biotic depletion is occurring on a global scale, mainly as a consequence of anthropic activities, which lead to habitat loss, fragmentation, and degradation and are considered major threats to biodiversity, additionally, their effects differ between species. Biotic homogenization is an ecological process occurring both between and within biological communities, in which they tend to become more similar at the taxonomic, functional, or genetic level. Due to the large number of small remnants of vegetation varying in structure, the Cerrado becomes the appropriate landscape model to test hypotheses associated with the effect of habitat quality on small non-flying mammal communities. In this context, I investigated the occurrence of the process of biotic homogenization due to changes in habitat quality in fragments of the Cerrado biome. In the present study the following hypotheses were tested: (i) patch size and habitat quality influence community structure, in a sense that smaller patches or patches with lower quality should have lower species richness and diversity (alpha and functional); (ii) changes in land use would alter the structure of the small mammal communities, thus, managed habitats should have lower richness and diversity (alpha and beta) than fragments of native vegetation; and (iii) changes in land use cause functional homogenization of the small mammal communities. We sampled five fragments of native vegetation, with semi-deciduous forest and four areas of agricultural cultivation, all located in the Triangulo Mineiro region, Minas Gerais state using Sherman-type traps. In sum, the sampling effort was 10800 trap nights, resulting in 539 captures of 282 individuals, wich belonged to 12 species: 2 marsupials (Gracilinanus agilis and Didelphis albiventris) and 10 rodents (Akodon montensis, Oligoryzomys spp, Rattus rattus, Rhipidomys macrurus, Oecomys cleberi, Hylaeamys megacephalus, Calomys spp. and 3 other rodent morphospecies. The proposed hypotheses were partially supported. It was expected that there would be an influence of habitat size and quality on local or functional richness and diversity, which was not proven. However, there is a process of taxonomic and functional homogenization in the agricultural cultivated areas, and the managed areas showed a loss of species and fauna restricted to species that tend to proliferate in disturbed environments. Thus, we emphasize the importance of better understanding the influence of human activities in the process of biodiversity degradation for its conservation.