Tongji University, Shanghai, China (People's Republic)
Abstract Submission: Due to the dual influence of natural and human activities, the landscape pattern of Dongting Lake wetland is undergoing accelerated evolution. In order to explore the trend of wetland ecological pattern evolution, 6 representative Landsat images from before and after the completion of the Three Gorges Project on the Yangtze River were selected for classification using Support Vector Machine (SVM), Maximum Likelihood (ML), and CART Decision Tree (DT) algorithms. The dynamic degree and transition matrix models were utilized to analyze the dynamic evolution characteristics of wetland patterns, leading to the construction of the Pressure-State-Response (PSR) model for ecological health assessment. The results showed that the CART decision tree algorithm exhibited high accuracy and stability. Dongting Lake wetland landscape was characterized by complex dynamics, increased fragmentation, and enhanced heterogeneity. The water area increased from 680.59 km² to 913.47 km², but due to the construction of the Three Gorges Dam, the area sharply decreased between 2001 and 2004. Sand mining in the lake area led to a reduction in mudflat area at a rate of -8.8 km²/a. The sedge and reed areas interconverted, and the woodland area significantly decreased after peaking in 2016. The ecological health values in 1995, 2001, 2004, 2010, 2016, and 2022 were 0.345, 0.635, 0.444, 0.661, 0.425, and 0.335, respectively, showing an overall fluctuation from “sub-healthy” to “very healthy” and back to “sub-healthy”. To address the natural-social drivers such as the impact of frequent extreme weather events and the construction of the Three Gorges Dam on wetland health, it is necessary to comprehensively consider the balance and coordination between socio-economic development and the natural environment. Strategies including optimizing water resource management, controlling human activity intensity, and increasing investment in wetland restoration have been proposed, providing scientific basis and practical guidance for wetland protection and management.
