多时空尺度下典型堰塞湖和构造湖流域土地利用与水质变化的关系对比研究OACHSSCD

To investigate the relationship between land use and water quality variations in different lake types,this study employed redundancy analysis(RDA)to quantitatively reveal the differential responses of water quality characteristics to land use patterns in barrier lakes(Mahu Lake)and tectonic lakes(Qionghai Lake)in southwestern China,utilizing multi-spatiotemporal scale land use and water quality monitoring data.The results demonstrated that:(1)Both watersheds were predominantly characterized by forestland and construction land,with Mahu Lake exhibiting higher forest coverage while Qionghai Lake was dominated by construction land.The Qionghai watershed displayed greater land use diversity compared to Mahu Lake.Spatial scale expansion enhanced patch adhesion and stability with increased shape complexity in Mahu Lake,whereas Qionghai's dominant construction land patches showed reduced dominance,reaching maximum aggregation at the 300 m riparian buffer scale.(2)Both lakes exhibited superior water quality during dry seasons(Class II standards)compared to wet seasons(predominantly Class III standards),with Qionghai Lake demonstrating significantly higher water hardness,salinity,and dissolved solids content exceeding standard limits.(3)The interpretation rates of all axes of water quality in the two lakes showed a positive correlation with the spatial scale,and the interpretation rate was higher in the wet season than in the dry season,and the highest spatiotemporal scales of the interpretation rates in the two lake basins were the 500 m lakeshore buffer zone(Mahu)in the wet season and the 400 m lakeshore buffer zone(Qionghai)in the dry season,with the interpretation rates of 98.97%and 99.13%,respectively,The main explanatory variables of Mahu Lake are COHESION,grassland,and construction land,and the main explanatory variables of Qionghai are construction land,AI and LPI.(4)Forestland and grassland generally demonstrated negative correlations with total dissolved solids and sodium chloride concentrations while positively correlating with dissolved oxygen,indicating water purification functions.Conversely,construction land and cropland exhibited negative impacts through pollutant inputs and soluble solids accumulation,promoting eutrophication.Landscape complexity degraded water quality,particularly through construction land dominance in the Qionghai watershed.This comparative study elucidates differential mechanisms of land-water interactions in distinct lake types,providing theoretical foundations for optimizing land use configurations and implementing targeted ecological protection strategies in heterogeneous lake basins,thereby facilitating sustainable human-lake ecosystem co-development.