Ecosystem Health Assessment of the Liaohe Estuary Suaeda heteroptera Wetland Based on a Coupled PSR–Entropy Weight–PLSR Model

The Suaeda heteroptera wetland in the Liaohe Estuary is a typical coastal wetland in northern China. This study presents a coupled PSR–entropy–PLSR model to assess ecosystem health and its driving factors, using long-term Landsat data from 1995 to 2024. The results show that the Ecosystem Health Index (EHI) dropped from 0.61 in 1995 to 0.20 in 2010, and then rebounded to 0.66 in 2024. The PLSR analysis identified four key drivers: Suaeda heteroptera carbon storage, mean patch area, aquaculture development intensity, and vegetation recovery rate. The simplified PLSR model constructed using these indicators achieved a cross-validation R2 of 0.967. This coupled model provides a simple, efficient, and reliable method for the rapid assessment and long-term monitoring of coastal wetland ecosystem health.