Environmental zoning of the Formoso river watershed, Bonito – Mato Grosso do Sul/Brazil

Abstract

Study karst landscapes involves engaging with systems that remain underexplored from an environmental perspective and are increasingly subjected to intensive human activity. These landscapes have been progressively fragmented by monoculture practices, primarily due to the natural fertility associated with limestone-rich soils and the flat terrain that facilitates agricultural expansion. This research proposes an environmental zoning model based on the analysis of landscape units, water quality, and the karst system, aiming to improve watershed management and offer a framework applicable to other karst regions, using as a pilot area that of the Formoso River Watershed (FRW), located in the municipality of Bonito, Brazil, taking into account key landscape components such as lithology, precipitation, topography, soil characteristics, land use and land cover, and water resources. To achieve this, Geographic Information Systems (GIS) were utilized—specifically, ArcGIS 10^® and Spring 5.2.7—for the collection and spatial analysis of environmental indicators. Field surveys were conducted to complement and validate the mapped data, enabling a more detailed and accurate representation of the study area. The results revealed the spatial heterogeneity of the FRW landscape, allowing for the identification of five primary zoning categories: Permanent Preservation Zones, Recovery and Rehabilitation Zones, Special Management Zones, Sustainable Use or Maintenance Zones, and Urban Zones, along with ten subzones. Each of these zones offers a framework for physical-territorial planning in a context marked by rapid land occupation and use, particularly the expansion of soybean cultivation in karst environments. The environmental zoning proposed in this study serves not only as a tool to guide public policy and land management decisions, but also as a contribution to the broader understanding of karst systems. It underscores their environmental fragility and structural complexity, especially under mounting agricultural pressure, and reinforces the need for targeted mitigation strategies and further scientific investigation.