Long-term ecological changes in China’s Ramsar sites

Abstract

Wetlands are globally critical for human survival and Earth's sustainable development. However, wetlands are experiencing rapid degradation and loss due to pollution, reclamation, climate change, invasions, etc. Ramsar sites are globally recognized as wetland hotspots that have been designated Wetlands of International Importance under the Ramsar Convention. However, the long-term trends of change that affect these sites remain unclear. This study explored the ecological changes and characteristics of Ramsar sites using 7 ecological indicators from three aspects: vegetation status, hydrological dynamics and anthropogenic disturbance, with the support of 36-year dense Landsat imagery and the trend and mutation analysis algorithms of Theil-Sen and BreakoutDetection. The results showed that (1) for the long-term trend, the ecological status of 55% of China's Ramsar sites experienced a trend of degradation, and the remaining Ramsar sites showed a trend of restoration in the past 36 years. (2) After the mutation was analysed, 47% of the Ramsar sites showed an environmental and ecological improvement trend in the recent period. (3) More than 50% of Ramsar sites were found to have ecological reversals in vegetation status and hydrological dynamics in the past 36 years.

Keywords

• Ramsar sites
• Time series analysis
• Ecological assessment
• Mutation analysis