Análise integrada da paisagem e processos de erosão costeira na ilha de Atalaia, Salinópolis, Pará

Abstract

The study aims to analyze the landscape and erosion susceptibility processes on Atalaia Island, Salinópolis, Pará, as a basis for coastal management policies. The objective unfolds in examining the coastline position between 2002 and 2022, identifying coastal dynamics through geoindicators, analyzing landscape units, and the degree of susceptibility to erosion on the island. To achieve the objectives, the study area was divided into three sectors: Espadarte, Atalaia, and Sofia. The materials and methods used include satellite images for a twenty-year multi-temporal analysis, with polygon change analysis techniques, areal and linear rates. For this assessment of coastal changes, the Digital Shoreline Analysis System (DSAS) plugin was used in the Geographic Information System environment of ArcMap 10.5. The use of geoindicators was granted through field sheets with the identification of natural or anthropogenic elements that pointed to the movement of the coastline. For the landscape analysis, the theoretical basis of landscape geoecology and the use of geoprocessing to generate a map of landscape units were used. The study revealed areas of high susceptibility with 47,798m², mainly in sector A, in this sector, geoindicators such as the front strip of vegetation modified by erosion (44) and the presence of retaining walls and other constructions in contact with the beach arch or on the surface of estirance (64) stand out. The areas of moderate susceptibility were present, prominently in Sector B, with an area of 66,950m², in this sector, the geoindicators of water/sewage piping or energy poles, located on the beach arch in a situation of destruction by physical agents (54) and the presence of retaining walls and other constructions in contact with the beach arch or on the surface of estirance (62) stand out. The areas of low susceptibility to erosion were present, most evidently, in Sector C, with an area of 341,274.1m², in this sector, the geoindicator related to the width of the post-beach/sandy berm surface (70) stands out. The results of the landscape analysis allowed the understanding of the structure and functioning of the fluvio-marine plain, urban areas, open areas, moving dunes, and beach and post-beach. The investigation offers a dynamic perspective on the erosion processes of Atalaia Island from the employed methodology, thereby, the results indicate the need for more effective coastal management strategies, underlining the importance of an integrated approach that considers both physical and socioeconomic aspects to mitigate adverse impacts on local communities and the ecosystem.