Evaluation of alpine wetland ecological degradation based on alpine wetland degradation index: A case study in the first meander of the Yellow River

Abstract

The alpine wetlands are vital in regulating climate, maintaining biodiversity, stabilizing ecosystem balance, maintaining water resources and ecological security. However, influenced by extreme climate and human activities, the ecological degradation of alpine wetlands seriously threatens the sustainable development of the region. Nowadays, it is urgent to develop an ecological monitoring index suitable for high-altitude alpine wetlands, and timely carry out long-term remote sensing monitoring and evaluation on the ecological degradation and restoration of alpine wetlands. Based on Landsat images of Google Earth Engine (GEE) year by year, we constructed the Alpine Wetland Degradation Index (AWDI) and studied the ecological change process of alpine wetland in the first meander of the Yellow River during 1990–2022 with the help of the Unary linear regression, the Theil-Sen median and the Mann-Kendall test methods. In addition, we also discussed the main driving factors of ecological degradation of alpine wetlands with the help of the Pearson correlation analysis and Geodetector. Our research found that the AWDI based on long-time series MNDWI, NDVI, FVC and WET has significant accuracy in evaluating the ecological degradation of alpine wetlands (POA = 95.69 %, Kappa = 0.9460). In the past 33 years, the ecological situation of the alpine wetland in the first meander of the Yellow River has experienced a process of degradation first and then improvement. Precipitation is the main factor that affects the ecological change of the alpine wetland, and the role of human activities can not be ignored. Our AWDI can quickly and accurately reveal the ecological degradation process of alpine wetlands, and then provide a scientific basis and case reference for the evaluation, restoration, management and protection of alpine wetland degradation.