Analysis of Hydrological Connectivity Dynamic and Important Patches in the Zoige Wetland

Hydrological connectivity plays an important role in the structure and function of wetland ecosystems. In recent years, the Zoige Wetland has experienced varying degrees of degradation due to human activities and climate change, significantly altering its hydrological connectivity. To quantify changes in hydrological connectivity and identify key wetland patches in the Zoige Wetland, we collected Landsat remote sensing data from 1977 to 2020 and utilized the supervised classification method to extract its wetland patches and analyze their area changes. Also, we employed the landscape connectivity index based on the graph theory to analyze the dynamic changes in hydrological connectivity from 1977 to 2020, and the importance index to identify key wetland patches. The results show a reduction of 10.60% in the Zoige Wetland area from 2 660.50 km² in 1977 to 2 378.53 km² in 2016. However, from 2016 to 2020, the wetland area gradually recovered to 90.78% of its extent in 1977. The structural and functional connectivity of the Zoige Wetland exhibited a temporal pattern of initial decline followed by subsequent recovery. In 2016, the structural and functional connectivity were 65.51% and 60.73% of its extent in 1977, respectively, and recovered to 70.23% and 72.39% by 2020. Notably, key wetland patches are primarily located within the protected area, suggesting that the ongoing wetland conservation and restoration measures play an important role in restoring the hydrological connectivity of wetlands.