Análise da Dinâmica do Uso e Ocupação do Solo da Bacia Hidrográfica do Rio Mearim

Abstract

RESUMO As bacias hidrográficas são unidades territoriais para a aplicação da Política Nacional de Recursos Hídricos, sendo analisadas como unidades de gerenciamento e planejamento. A bacia do rio Mearim é a maior do Maranhão, com uma área de 99.058 km² - equivalente a 29,84% do território maranhense, ela tem suas nascentes e foz localizadas dentro do Estado. Este trabalho teve por objetivo avaliar as alterações no uso e ocupação do solo que ocorreram sobre a área da bacia hidrográfica do rio Mearim. Foram utilizados dados da coleção de imagens 5.0 do projeto Mapbiomas referente ao período de 1985 - 2019 através de análises e procedimentos feitos em ambiente SIG, utilizando o software livre QGIS 3.16.3 – Hannover, que resultaram em mapas, gráficos e tabelas que expuseram a dinâmica espaço-temporal na bacia do Mearim, constatando se as perdas de habitats naturais tanto em quantidade como em qualidade, que reconfiguraram negativamente a paisagem natural da região. Com destaque para as áreas de vegetação natural - em que nota-se a maior perda na classe de formação floresta; e também o aumento exponencial das áreas destinadas ás pastagens. A bacia mostrou-se muito antropizada, revelando crescimento progressivo e desordenado, por esse motivo, o presente estudo proporciona suporte para tomada de decisões em políticas públicas que poderá colaborar para um melhor planejamento voltado a gestão ambiental.__ABSTRACT: The hydrographic basins are territorial units for the application of the National Policy of Water Resources, being analyzed as management and planning units. The Mearim river basin is the largest in Maranhão, with an area of ​​99,058 km² - equivalent to 29.84% of the territory of Maranhão, it has its sources and mouth located within the state. This study aimed to evaluate changes in the use and land occupation that occurred over the Mearim river basin area. Data from the 5.0 image collection of the Mapbiomas project referring to the period 1985 - 2019 through analyzes and procedures carried out in a GIS environment, using the free software QGIS 3.16.3 – Hannover, which resulted in maps, graphics and tables that exposed the spatio-temporal dynamics in the Mearim basin, verifying whether the losses of natural habitats in both quantity and quality, which negatively reconfigured the natural landscape of the region. With emphasis on the areas of natural vegetation - in which there is the greatest loss in the formation class forest; and also the exponential increase of areas destined to pastures. the basin showed to be very anthropized, revealing a progressive and disordered growth, due to For this reason, the present study provides support for decision making in public policies that can collaborate for a better planning focused on the management environmental.___SUMMARY The hydrographic basins are territorial units for the application of the National Policy of Water Resources, being analyzed as management and planning units. The Mearim river basin is the largest in Maranhão, with an area of ​​99,058 km² - equivalent to 29.84% of the territory of Maranhão, it has its sources and mouth located within the state. This study aimed to evaluate changes in the use and land occupation that occurred over the Mearim river basin area. Data from the 5.0 image collection of the Mapbiomas project referring to the period 1985 - 2019 through analyzes and procedures carried out in a GIS environment, using the free software QGIS 3.16.3 – Hannover, which resulted in maps, graphics and tables that exposed the spatio-temporal dynamics in the Mearim basin, verifying whether the losses of natural habitats in both quantity and quality, which negatively reconfigured the natural landscape of the region. With emphasis on the areas of natural vegetation - in which there is the greatest loss in the formation class forest; and also the exponential increase of areas destined to pastures. the basin showed to be very anthropized, revealing a progressive and disordered growth, due to For this reason, the present study provides support for decision making in public policies that can collaborate for a better planning focused on the management environmental.