Land Use/Cover and Naturalness Changes for Watershed Environmental Management (Southeastern Brazil)

Abstract

Driving forces on the landscape require regional management and/or local ac- tions, together with other external factors. To operationalize this approach, this paper carried out a comparative analysis of the naturalness dynamics of the Jacaré-Guaçu and Jacaré-Pepira watershed, based on land use/cover changes and a structural indicator of the landscape, over the 10-year (2004-2014), as support opportunities for improving its environmental plan- ning and management. Land use/cover dynamics were obtained based on screen digitizing of LandSat imagery, using polygon manual digitalization. Naturalness scenarios of the watersheds, over the 10-year (2004-2014), were obtained based on Urbanity Indicator, which evaluates how much the natural landscapes are dominated by altered systems. The total area of watersheds showed a predominantly scenario, induced by anthropogenic agricultural and non-agricultural expansion areas, mainly by conversion of other land use/cover types in sugarcane cultivation. Despite the increase in natural vegetation areas, over the 10-year (2004-2014), Jacaré-Guaçu and Jacaré-Pepira water- sheds are far from a sustainable condition. However Jacaré-Guaçu watershed presents a scenario of more committed naturalness due to the increase in Ur- banity Index values ≥ 0.7. The historical process of land use occupation for agricultural production remains the main driving force of naturalness changes, occupying more than 70% of the total area of watersheds. These re- sults have significant implications for fast urbanizing municipalities in pro- viding key information about long term land use impact on the watershed structure and function, making it possible for policy makers, scientists and R. T. Costa et al. stakeholders to identify land uses which are hindered or enhanced under var- ious scenarios of land use change over the time, and making it possible to ex- plore the trade-offs between them to improve watershed management.