Mapeamento e diagnóstico da vulnerabilidade ambiental da Serra de Santana, região do Seridó-RN

Abstract

Environmental planning and management in this century are important issues for society. The study of environmental vulnerability aims to indicate the potential and limitations of land use in the face of anthropogenic pressures on environmental systems and to contribute to an understanding of spatial reality in order to direct land management and planning. Historically, the Santana mountain range has been occupied by agricultural practices, but in recent years its spatial dynamics have undergone significant changes, with the advance of urbanization and anthropisation of this humid enclave, leading to the degradation of native vegetation and changes in land use. The aim of this research is to map and diagnose the environmental vulnerability of the Serra de Santana, in the Seridó region of Rio Grande do Norte, based on a systemic analysis of environmental variables and multi-criteria analysis using map algebra. To this end, maps of the study area's environmental variables were generated: Relief Dissection Index (RDI), Declivity, Geology, Vegetation, Pedology and Rainfall. In addition, temporal mapping of Land Use was carried out to analyze and quantify the changes resulting from use/cover and the mapping of Landscape Environmental Systems, based on an integrated analysis of the environmental components, to support the diagnosis of the systems mapped for the Santana mountain range. The results of the Land Use Mapping showed that its spatial distribution has undergone significant changes over the years, especially with the increase in wind farms, areas of degraded caatinga and exposed soil, with a consequent reduction in dense vegetation, which corroborates the anthropogenic influence on the systems, as the results indicate significant environmental degradation in these areas. Seven classes of environmental systems were mapped for the study area. Of these systems, the Residual Crests and Abrupt Escarpments, Dissected Eastern Slope and Subhumid Western Slope classes were more susceptible to degradation, with a moderate to high degree of environmental vulnerability. On the other hand, the Serrano Plateau and River Plains and Alluvial Tablelands environmental systems were moderately stable to moderately stable/vulnerable, configuring transitional environments with a tendency towards stability. The Environmental Vulnerability Mapping showed five vulnerability classes for the study area: Stable, Moderately Stable, Moderately Stable/Vulnerable, Moderately Vulnerable and Vulnerable. The Stable and Moderately Stable classes occur to a greater extent in the plateau areas, the edges of the relief that are more preserved in terms of land use, being on favorable relief over stable lithologies and soils. However, the Vulnerable class was classified in areas of steep relief, with a high level of dissection and in areas dominated by anthropogenic activity. The map of environmental systems corroborates the territory's environmental vulnerability, in which there are classes with a high potential for ecodynamic fragility and systems with medium to moderate vulnerability. It is therefore hoped that this research will contribute to understanding the environmental dynamics of the landscape in this area of significant landscape/ecosystem interest, and that it will help in the management and planning of these areas with a view to conservation and the sustainable development of the territory.