鄱阳湖典型洪泛湿地生态系统时空尺度分析

[Objective] The Poyang Lake floodplain wetland ecosystem plays an irreplaceable role in regulating the hydrology of the Yangtze River Basin and maintaining biodiversity. However, due to the combined effects of climate change and human activities, problems such as water quality deterioration and vegetation community degradation have become increasingly prominent, highlighting the urgent need for systematic investigation. This study aims to address two core scientific questions by constructing a multi-element collaborative analytical framework: (1) to reveal the spatiotemporal change patterns and driving mechanisms of wetland water quality under the dual stress of climate change and human activities; (2) to analyze the combined impact of hydrological regime shifts and land use pattern changes on vegetation community structure and benthic species communities. [Methods] This study integrated multi-source data fusion and spatiotemporal coupling analysis techniques. Six typical monitoring sites were selected, covering three types of habitats: dish-shaped lake areas, tailing areas, and flood detention areas. Water quality parameters (e.g., DO and TP, six indicators in total) and benthic species data were obtained through continuous observations during three hydrological periods (normal, flood, and dry seasons) in 2024. Remote sensing image interpretation was used to obtain land use changes and vegetation conditions. Based on water quality index (WQI), Pinkas’ index of relative importance (IRI), and other methods, the spatiotemporal change characteristics of the wetland ecosystems were systematically analyzed. [Results] (1) The WQI of the Poyang Lake floodplain wetlands was influenced by both temporal and spatial scales. Temporally, it exhibited a migration pattern of pollutants characterized by “dilution in the flood season and enrichment in the dry season”. Spatially, it exhibited a gradient pattern of “poorer conditions in the upper and middle reaches and better conditions in the lower reaches”, with the best water quality observed in the dish-shaped lake areas, while the overall wetland water quality reached the “good” level (60[Conclusion] This study identifies three types of ecological problems in the Poyang Lake floodplain wetlands. The first is the “water quality imbalance under the combined effects of hydrological regimes and human activities”, characterized by significant seasonal variations in pollutants, following a pattern of “dilution in the flood season and enrichment in the dry season”. The second is “degradation of biological community structure and decline in ecological functions”, characterized by deterioration of vegetation community structure, disappearance of high-density areas, reduction of medium-density areas, and lower biomass of benthic species in areas with frequent human activities compared with natural ecological areas. The third is “conflict between land use and ecological functions”, characterized by adverse changes in land cover, forming a positive feedback chain of “farmland encroachment-non-point source pollution-vegetation degradation”. A coordinated governance system of “hydrological regulation-ecological restoration-social participation” is proposed to address these three types of problems. In future, the monitoring scope can be further expanded, and long-term research on the response of wetland ecology to climate change can be strengthened to provide more comprehensive scientific support for sustainable wetland management in the context of the Yangtze River protection strategy.