Análise de Atributos Fisiográficos em Ambientes Litorâneos da Planície Costeira do Nordeste Paraense

Abstract

The coastal plain of northeastern Pará, located between the Marajó Bay (0° 30'S and 48° 00' W Gr.) and the Gurupi river bay (0°30'S and 46° 00' W Gr. ) is about 500 km long, with a variety of ecosystems, such as restingas and mangroves, ecotones between continental and marine environments, and is integrated by physiographic elements such as watershed geometry, different geological substrates, topography, landforms, soil composition, and vegetation formations. The study is based on the landscape ecology approach that presents three basic characteristics for ecosystem studies with different spatial representations: 1) structure, which is the product of spatial relationships between distinct ecosystems, 2) function, which represents the interactions between spatial elements, and 3) change/change, resulting from alteration in the structure and function of the environmental/ecological mosaic over time. The ecosystems studied are then described and characterized from their characteristic physiographic elements, such as geological substratum, morphology, sediment type, soil type, and associated vegetation cover, existing in publications, maps, and photographs. Field trips, important for the knowledge of the structural and spatial elements that compose the landscape units, facilitate the understanding of the conceptual basis and the interaction of the different landscape elements in its multiple spatial scales, from the field work to its cartographic representation (thematic map). The survey of the elements that constitute the coastal landscape allows the ordering of its physiographic elements in a representative matrix of the study area. The coastal landscape units represented in the matrix are the mangroves and the restingas, followed by the continental terra firme. The restingas have 6 other subunits, which do not occur in the whole study area. The Landscape Ecology approach, generating landscape units at different geographical scales, ordered and integrated in a physiographic matrix is useful for a planning of use/preservation/conservation of coastal ecosystems, allowing their comparison and the definition of their multiple spatial scales and structures.