Use of Multi-Source Remote Sensing Data to Understand Long-Term Wetland Dynamics and Water Environment Responses in the Chaohu Lake Basin

Abstract

Wetland ecosystems in large lake basins play a critical role in maintaining regional water security and ecological balance. Despite their importance, the long-term spatiotemporal dynamics of basin wetlands and their effects on lake water quality under intensive human disturbance remain elusive. This study leveraged multi-source satellite archives from 1986 to 2025 to construct a framework for extracting and classifying potential wetlands in the Chaohu Lake basin, Anhui province, China, and examined its evolution and its relationship with water quality. The resulting wetland maps are highly reliable, with overall accuracy ranging from 81.63% to 94.22% and precision approaching 99%, effectively addressing spectral confusion and boundary instability caused by hydrological fluctuations. In total, the basin contains approximately 2139.9 km2 of potential wetlands (16%), which are spatially concentrated along the lake and river corridors. Over the 36-year period, wetlands underwent distinct phases of “relative stability—rapid decline—Emerging recovery,” with shrinkage primarily in the west and relative stability in the east, while ponds and paddy fields experienced the most frequent conversions. In recent years (2010–2025), changes in the water environment of Lake Chaohu showed strong spatiotemporal consistency with wetland dynamics. As partial wetland recovery emerged after 2015, concentrations of total nitrogen (TN), total phosphorus (TP), and chlorophyll-a (Chla) declined and stabilized, and the area affected by cyanobacterial blooms decreased by 46%, suggesting a potential role of wetland recovery in improving water quality and mitigating non-point-source pollution. This study provides a comprehensive characterization of wetland dynamics and their influence on water quality, offering valuable data and guidance for wetland conservation, ecological restoration, and integrated lake management in the Chaohu Lake Basin.