Da análise sistêmica à Serra de Martins: contribuição teórico-metodológica aos brejos de altitude

Abstract

Environmental systems must be understood as complex formed by its own elements (e.g., rocks, landform, soil, water bodies and land cover) and their processes and interactions, constantly driven by matter and energy flows. Thus, the present investigation used systemic metodologies aiming to identify and delimit the geoenvironmental units present at the Serra de Martins. This investigation is composed of six chapters, where at the first chapter it was established theoretical discussions of concepts designed in the light of systemic analysis, highlighting the theoretical and methodological evolution of the geosystemic theory. Furthermore, this chapter draw a discussion of the Brejo Forest at the Brazilian Northeast region. At the second chapter, it was characterized the climatic traits of the Serra de Martins region aiming to compare and differentiate it from the surrounding regions. For achieving that, it was used the the last 30 years historical series of the temperature and precipitation at the counties of Antônio Martins and Martins. These data provide support to a posteriori water balance analysis. As a result, it was established that the Serra de Martins exhibits climatic characteristics influenced by altitude. In the third chapter, it was characterized the geological and geomorphological aspects of the study area, based on a survey of secondary data, cartographic and field works. It allowed the observation that the Serra de Martins is built on crystalline soils of various lithologies with the occurrence of concentrated sediment capping the flat areas of the Chapada. It was further concluded that the landforms present in the area are subject to different lithostratigraphic units and are classified in denudational and agradacionais units. The fourth chapter provides a characterization of the study area soils, which was based on the physical and chemical analysis of samples collected in 20 points. Furthermore, clustering statistical analysis was used in order to provide the soil groups. Thus, the discussion of the results has established the pedological compartmentalization of the study area into three groups: Lownlands area, Slopes and Plateau. In the fifth chapter it was based how is the soil occupation at the Serra de Martins region, were the following land cover classes were identified: Semideciduous Seasonal Forest, Savannah-Estépica Forested, Savannah-Estépica Tree, Permanent Agriculture, Temporary Agriculture, Bare Soil, Urban area and water bodies. The above chapters were of fundamental importance to the development of the last chapter where geoenvironmental compartmentalization of the area was attempted and anchored in multivariate data analysis. Thus, in the study area, the following environmental units have been identified: facies 1: recessed surfaces Relief Plan Gentle Undulating in the Crystalline Basement with Savannah-Estépica Tree on Luvisols; facies 2: Lowered Surface Busy relief in the Crystalline Basement with savannah-Estépica Tree on Acrisols Red Yellow Eutrophic; facies 3: Escarpment Serranas of Busy relief in the Crystalline Basement with savannah-Estépica Forest on Leptosols; facies 4: Tabular Surfaces Plan Relief in Basement Sedimentary with semideciduous forest on Ferralsols Yellow Dystrophic; facies 5: Escarpment Serranas with relief Gentle Undulating in the Crystalline Basement with Savannah-Estépica Forested in Leptosols; facies 6: Escarpment Erosive of Busy relief in the Crystalline Basement and Sedimentary Cover with semideciduous forest on Ferralsols Yellow Dystrophic. Thus, based on the perspective of Brejo Forest and taking in consideration the constituent elements and their interactions, it was possible to identify the facies 4 of the Serra de Martins must be understood and termed as Chapada de Martins Altitude Swamps.