The degradation of the last remaining spawning grounds of the critically endangered Chinese sturgeon (Acipenser sinensis) exemplifies the global crisis of dam-induced riverine ecosystem degradation. By integrating geo-detector-weighted hydrodynamic parameters with landscape connectivity metrics, we develop a novel habitat suitability framework that quantifies previously overlooked mechanisms: First, hydrodynamic thresholds (e.g., turbulent intensity, depth, shear velocity) emerge as primary drivers of habitat selection, with parameter interactions amplifying explanation by 56.25% compared to single-factor assessments. Second, dam impoundment and channelization led to an 81.82% reduction in highly suitable habitat (2012 vs. 1999), driven by hydrological alteration, riverbed erosion and habitat fragmentation (patch density increased 91.50%, connectivity decreased 65.06%). These changes directly contributed to a 99.96% decline in egg density, forcing the species to shift to suboptimal upstream zones where reproduction ceased since 2013. To reverse these declines, we propose flow optimization (10,000-15,000 m³/s spawning season discharge) to manage turbulence thresholds and cobble rehabilitation to restore bathymetry conditions, strategies expected to restore 56.13-72.80% of Landscape-Integrated Geo-Detector Weighted Usable Area (WUA_GL). This study fills critical gaps in traditional habitat models and provides a replicable framework for conserving dam-affected freshwater ecosystems through actionable, threshold-based management.
 

sturgeon; Spawning ground; Eco-hydraulic modeling; Geo-detector approach; Landscape indices; Analytic hierarchy process; Habitat suitability model; Yangtze River