Características ambientais de fragmentos da mata atlântica: sua relação com a estrutura de habitat e métricas de paisagem

Abstract

This dissertation consists of two articles. In the first, it was made a review about habitat structure. Searches were realized in the Scopus research base, with the help of keywords in English. The searches of bibliography took place over 12 months and the articles selected for reading were analyzed as to the methods used and results obtained. The habitat structure is fundamental for occurrence, establishing behavioral and social patterns of various species. It is still difficult to identify which structures are considered as a "key" for the occurrence of each Taxa due to the lack of repeatability of studies aimed at studying the relationships between the habitat structure and the patterns of each Taxa. Some structures deserve attention because they have been related to the increase in the occurrence of different species: forest cover, type of soil cover, soil properties, diversity of trees, average vegetation height, understory opening, canopy height, cover and burlap depth. Only a few structures have actually been identified as a key structure, which is the case of forest cover, in relation to the basic organization of the frugivory networks and richness of mammal species, as well as the forest stratification for the occurrence of temporary birds and swamps, for occurrence of various Taxon. In the second article, the relations between habitat structure and landscape metrics were tested. Areas of 60 m x 20 m were selected in 30 landscapes spread over Minas Gerais, São Paulo and Rio de Janeiro. In these areas, litter above the soil, soil samples for obtaining organic matter, opening the understory, opening and diversity of the litter, temperature and air humidity were collected. Mapbiomas' land use classification layers were used for the calculation of landscape metrics by the “Landscape” package, in Software R version 4.1. Using generalized linear models, the relations between habitat and landscape structure variables was tested. The increase in the number of fragments of natural forest tends to decrease the diversity of the litter and the organic matter found in a physical micro-habitat, because a bigger number of fragments means bigger fragmentation. This is corroborated by the result that shows that the central area of fragments of natural forest has a positive relation to the diversity of the litter and organic matter and negative to the minimum temperature, leaving the environment with more pleasant temperatures. The increase in the central and average area of planted forest fragments tends to have a greater amount of litter, this may be related to the type of species found in the fragment. The higher the average area and the perimeter-area ratio of fragments of natural forest, the maximum local humidity decreases because the greater concentration of trees together reduces exposure to high temperatures. These results are important to support the identification of important structures to generate environments conducive to the maintenance of local species, identification of the threshold of anthropic action on the habitat structure and assist the development of public policies and optimize the current methods of monitoring the conservation of fragmented areas.