Análise Geossistêmica Aplicada ao Estudo da Fragilidade Ambiental na Bacia Hidrográfica do Rio São João de Tiba-BA

Abstract

The watershed is understood as a complex system that integrates elements natural, socioeconomics and cultural. The objective of research was to assess the anthropogenic changes in the dynamics of landscape the River Basin São João de Tiba-BA and its interference in the fragility of environmental systems. The basin of 178. 071 hectares, is inserted in the Region of Extreme South Bahia, which was incorporated into the "development" of economic and private megaprojects like cellulose of extensive territorial occupation that this region has experienced, resulting in severe exploitation of natural resources and intense changes in the landscape. Thus, to understand the natural dynamics and the processes of land use and occupation were performed analysis physiographic, morphometric, socioeconomic diagnosis and characterization of the evolution of the use of land, identifying the major impacts of space appropriation process. To meet the proposed objectives, was adopted the scale 1:100.000. The research involved the use of cartographic techniques and remote sensing, through GIS. For this, we used radar image (SRTM and ASTER), and satellite images Landsat TM 5, information collected in fieldwork, and data socioeconomic nature. The data generation and preparation of maps was performed in SIG ArcGIS 10. The integrated analysis of the environment can be inferred that the area is characterized, mostly by plan relief of the Coastal Tablelands of Barriers Group, which originated evolved soils as Yellow Latosols, naturally covered by a rainforest that were gradually replaced. The basin comprises nine different environmental systems. The geo-environmental characteristics of the area were attractive for the development of the main forms of anthropism that changed the landscape and turned it into two types of scenarios: the of pasture and of eucalyptus. The use of land for pasture concentrates most of the arable land, and what else disrespects environmental legislation. The plantation of eucalyptus is agricultural use with the highest growth in the period analyzed, meanwhile, the remaining forest areas were reduced by 63%. The forms of land use practiced in the basin contributed to the increase in environmental degradation processes and, consequently, increasing its Environmental Fragility. It is hoped that the research can collaborate with the area of systems analysis in watersheds as a subsidy to the Environmental Planning.