Riparian zone transformation in South Africa: Evaluating changes, causes, and the role of legal frameworks

Abstract

• 30-year spatial analysis shows 35% rise in riparian land use. • Cultivation is main driver of riparian change, urban growth leads in Gauteng. • Recommends ILM and spatial policy alignment to strengthen governance. Riparian zones are important transitional ecosystems that exist between aquatic and terrestrial systems. These zones are rich in biodiversity and provide vital ecosystem goods and services to communities in South Africa and globally. Unfortunately, their ecological richness has exposed these systems to increasing degradation due to expanding anthropogenic pressures, notably agriculture and urbanisation. Using a mixed-methods approach, this study integrates a policy review with geospatial analysis using Land Use Land Cover (LULC) data and GIS-based mapping within a 50-meter riparian buffer in South Africa. Findings revealed a 35% increase in anthropogenic land use within riparian zones between 1990 and 2020, with cultivation accounting for over 90% of riparian land use nationally. Urban expansion was particularly intense in the Gauteng and North West provinces, elevating threats to water quality and biodiversity degradation within the riparian zone and broader riverine ecosystems. Despite multiple legal instruments acknowledging the ecological value of riparian zones, including the National Water Act and the National Environmental Management Act, their implementation remains fragmented. Most policies lack enforceable spatial thresholds or clear buffer guidelines, which may lead to unregulated encroachment. The absence of strong and coherent intergovernmental coordination undermines efforts to manage riparian zones effectively. This study underscores the need for more robust, spatially enforceable regulatory mechanisms, as GIS analysis revealed extensive anthropogenic encroachment into riparian zones. By linking observed land use changes to governance gaps, the findings support the adoption of Integrated Landscape Management (ILM) approaches, which can align sectoral mandates, guide spatial planning, and enhance the ecological integrity and long-term sustainability of riparian systems in South Africa.