Influência da matriz adjacente na diversidade e funções ecológicas de besouros escarabeíneos em fragmentos de Mata Atlântica

Abstract

Abstract: Habitat loss and fragmentation are among the main threats to biodiversity conservation and associated ecosystem services. Loss of area, increased isolation, and increased exposure to adjacent matrix disturbances promote changes with serious consequences for the structure and function of forest fragments. The role of the adjacent matrix, both the habitat and the effects of its management on the remaining natural areas remain poorly understood. Dung beetles (Coleoptera: Scarabaeidae, Scarabaeinae) compose an important group of insects, well represented in tropical regions and are very sensitive to changes in environmental conditions and habitat structure. These dung beetles can be used to evaluate natural or anthropogenic impacts on tropical forests. They perform important ecological functions by participating in key processes in ecosystems, such as nutrient cycling, aeration and soil aggregation, secondary seed dispersal, and control of vertebrate parasites. In this thesis, we evaluated the influence of the matrix adjacent to forest remnants on the dung beetles community and the functions of fecal removal, bioturbation and secondary dispersion of small, medium and large seeds. We collected dung beetles in 13 remaining forest areas, with total area ranging from 8.46ha to 49259.25ha. We selected seven of these areas, where we evaluated ecological functions. We conducted the survey of the canopy opening, slope, texture and chemical characterization of the soil, besides the landscape indexes, describing the size, isolation, and perimeter/area ratio of each studied area. To characterize the adjacent matrix influence, we calculated the proportion of the fragment boundary composed by intensive agriculture and conventional pasture. We collected 914 individuals, distributed in ten species, six genera and four tribes. We found from 73% to 100% of the wealth expected by the estimators for each area. The most abundant species was Canthon staigi (Pereira, 1953), with 669 individuals, occurring in 11 of the remnants studied. The increase in forest areas that border on pasture and intensive agriculture negatively affected the richness, abundance and biomass of the dung beetles. The proportion of the limit with intensive agriculture negatively affected the rates of bioturbation. The abundance and biomass of rollers were responsible for most of the services except medium and large seed dispersal. The loss of ecological functions can promote changes in different components that regulate ecosystem services, leading to irreversible processes in the remaining areas. Thus, in addition to comparing different forms of land use, future studies should consider the management of the adjacent matrix in the evaluation of disturbances in remnant forest areas