Estrutura e dinâmica atual das unidades de paisagem da bacia hidrográfica do Arroio Guaçu – Paraná

Abstract

The potential of ecosystem resources and services provided by landscapes fosters the development of socio-economic and socio-cultural activities in watersheds. However, insufficient understanding of the structure and dynamics of landscapes can lead to diverse socio-environmental impacts, threatening the dynamic equilibrium of this complex geographical entity that is the watershed. In this context, the objective is to analyze the structure and current dynamics of the landscape units in the Arroio Guaçu Watershed (BHAG), Paraná, Brazil. Additionally, the study aims to understand the socio-environmental impacts and transformations present in the identified natural and socio-natural units. The theoreticalmethodological framework focuses on: landscape and the geosystem analysis; landscape geoecology; landscape cartography; watersheds; and socio-environmental impacts and impact matrices. The theoretical guidelines enable the integration of natural and social variables that shape the landscapes analyzed in the BHAG. The methodology for mapping the landscape units adheres to the principles, methodological, and technical principles of landscape cartography, integrating geospatial elements into four taxonomic levels: 1st level – slope and hypsometry (morphometry); 2nd level – results of the 1st level combined with soil information; 3rd level – results of the 2nd level combined with phytogeography information (natural landscapes); 4th level – results of the 3rd level (or natural landscapes) combined with land use and land cover information (socio-natural/transformed landscapes). The mappings reveal 24 natural landscape units, which, when influenced by land use and land cover, are transform into 132 socio-natural landscape units, divided into three major geosystemic units: lower, middle and upper course. To understand the socio-environmental impacts and landscape transformations, impact matrices and geoecological profiles are used, interpreted through a geosystemic approach. Through geoprocessing, fieldwork, and the application of 67 socio-environmental impact matrices throughout the BHAG, it was possible to understand the current dynamics of the identified units and the transformative agents of these landscapes. The results indicate that socio-environmental impacts stem from multiple agents, with particular emphasis on extensive temporary crops, which have reduced native vegetation and enabled the establishment of other associated land uses, such as fish farming. These land uses have resulted in a weakened fauna, erosion-prone soils, and the proliferation of exotic fish species in artificial lakes in the lower slopes and tributaries of the Arroio Guaçu. It is believed that this research can support planning and management actions aimed at the proper management of the BHAG, with the identified and analyzed landscapes serving as a starting point.