Fitoecologia de bacias hidrográficas semiáridas: experiência a partir da cobertura da terra e morfoestrutura do relevo

Abstract

The landscape is a system formed by the trinomial: natural landscape, social landscape and cultural landscape. It is a category of the geosystem, the result of the relationships and integration of elements, man-society, biota-environment, among others that form this system. In this way, the delimitation of these landscape units contributes to the management of areas, helping to understand the functioning of the systems, pointing out weaknesses and environmental potential. Natural resources, in particular water, have suffered throughout the history of civilizations, great conflicts and pressures, being exploited with intensities that vary according to the historical, economic and technological context. In this context, the modeling of scenarios comprises projection tools that represent the changes occurring on the earth's surface, resulting from anthropogenic derivations on natural components, portraying the functioning of the landscape. In order to elucidate the issues mentioned above, the general objective is to understand the phytoecology of semi-arid watersheds: an experience based on land cover and relief morphostructure. Bearing in mind the hydrographic basin as a system, the methodological orientation of systemic analysis of the landscape will be used. Thus, system, the methodological orientation of systemic analysis of the landscape will be used. Thus, a survey of the physical and environmental aspects of the Seridó River Basin was carried out, analyzing information on the climate, geology, soil types, relief, hydrography, vegetation cover and later a cartographic base of the study area was produced. In summary, the methodological procedures of this scientific research were divided into three stages, which include the acquisition of materials (remote sensing images and cartographic material), the methods that will be worked on (in the field and in the laboratory) to obtain the respective results. Based on the assessment of the land cover, it can be seen that the BHRS is in a process of severe degradation. Where the conditions of severe land use over time alter the dynamics of the Caatinga, promoting the loss of native vegetation cover as well as water bodies. Affecting approximately 30% of the original vegetation cover of this Basin. Thus, the use of vegetation indices applied to satellite images proved to be relevant tools in the study of land cover for the study area. What makes it necessary, more studies that comprise quantitative surveys of the landscape at different levels and heterogeneity of scales, monitoring trends of changes in ecosystems. However, this study confirms the potential of using remote sensing images as a valuable method for determining the change in extent and distribution of land cover over time. Thus supporting the high demand for a more detailed representation of the Earth's surface, which is essential for mapping and developing a region. Using land cover analysis, as well as hypsometric data, we found that there is a considerable relationship between vegetation and each geomorphological unit. And for that, the systemic analysis of the results proved to be quite satisfactory in understanding the area of study. In this way, it is understood that the results obtained can help in the management and environmental planning of the Hydrographic Basin, since these constitute tools that offer subsidies based on the physical elements, being important with regard to the resolution of socio-environmental problems. It is worth mentioning that studies on vegetational aspects of the Caatinga are still incipient, and in this way, we hope that the description of each phytoecological unit and the explanations about the conditions that determine the distribution of each one will broaden the understanding of students and researchers about biogeography and encourage new research on the regional environment.