Serviços ecossistêmicos de provisão prestados pela caatinga: uma análise do uso e cobertura da terra do município de Acari

Abstract

Over the last few decades, natural landscapes have undergone significant transformations through the process of human use and occupation which, as a consequence, cause negative impacts on the components of the natural framework, with an emphasis on the ecological processes provided by ecosystems. In this sense, geographic research seeks to analyze the dynamics and processes operating in the landscape, centralizing the focus on studies on the forms of land use and cover and its ecological processes. Therefore, in an attempt to understand the dynamics of caatinga vegetation cover and ecosystem services, this research has as its spatial focus the municipality of Acari, which, located in the interior of Rio Grande do Norte, currently forms part of the delimitation of the Seridó Desertification Center. The present work aims to evaluate how forms of land use and coverage influence the provision of ecosystem services provided by the caatinga in the municipality of Acari (RN). To this end, initially, land use and cover mapping was carried out using images from the Landsat 5 (TM sensor) and Landsat 9 (OLI/TIRS sensor) satellite, made available by the United States Geological Survey (USGS), for the years 1987 and 2022, which went through a pre-processing stage for atmospheric and reflectance correction for subsequent supervised classification. In addition, the Normalized Difference Vegetation Index (NDVI) and the Soil-Adjusted Vegetation Index (SAVI) were calculated. The characterization of the vegetation cover was based on data obtained from the Flora do Brasil 2020 (REFLORA) system and the provision ecosystem services were classified based on The Common International Classification of Ecosystem Services (CICES) – both stages and validation of the data obtained through of geotechnologies, occurred based on field activities. As a result of the mapping, through analysis, similar values were observed in relation to the size of the occupation classes, in both mapped years. However, greater fragmentation of the landscape was observed through areas of pasture and temporary agriculture, throughout the flattened area. In this way, the lowered erosion surface showed a high rate of environmental degradation which, despite presenting a relevant diversity of plant species, the levels of anthropogenic disturbances and reduction in the density of vegetation cover are relevant, as a result of the inadequate use and management of services provision (pasture, agriculture and biomass exploitation). Regarding areas with topographical elevation, which correspond to residual reliefs, these presented a higher level of conservation, density and biological richness, with a predominance of rare species, at risk of extinction and typical of humid areas, which are associated with microenvironments of higher humidity provided by geomorphological features. In this sense, it is concluded that the municipality of Acari has a relevant territorial extension with a high level of soil degradation, where, based on this, it is necessary to take measures to recover these degraded areas, to prevent future impacts and further fragmentation of the landscape. Conversely, the mountain areas presented relevant biological diversity and preserved remnants of caatinga, therefore, they have the potential to reinforce decision-making for environmental conservation in high-altitude environments, in favor of maintaining the services provided by the caatinga and preserving biotic and abiotic diversity.