Wetland Evolution and Driving Force Analysis in the Qingtongxia Reservoir Area

Abstract

In recent years, the combination of river disruption and irrational human activities has caused serious damage to wetlands. Based on long-time-series remote-sensing images, this study applied the land use transfer matrix and landscape index method to investigate the dynamic evolution and driving forces of the Qingtongxia wetland in the upper reaches of the Yellow River from 1999 to 2020. The results show that the land use types of Qingtongxia wetland changed insignificantly from 1999 to 2020, with the area of water and grassland decreasing and the area of reed wetland, beach, farmland and forest increasing. The spatial changes in the watershed changed the distribution of other land uses within the wetland, with the watershed concentrating in a southwest–northeast direction and shrinking in the southwestern part of the wetland area between years. From 1999 to 2011, the wetlands were restored, the landscape became less fragmented and simpler in shape and the dominant species developed significantly. From 2010 to 2020, the wetlands were disturbed and, as a new tourist destination, the planning and renovation work increased fragmentation and the complexity of the patches. The complexity of the patch shape increased, and, at the same time, with the implementation of various conservation measures, the development of the dominant species within recovered. The drivers of change in the different land use areas within the wetlands of the Qingtongxia reservoir are dominated by flow, and the drivers of the evolution of landscape patterns within the wetlands are closely related to the population and gross regional product, in addition to being influenced by flow. In recent years, increased fragmentation has been the main reason for the decline in bird habitat quality. Maintaining bird diversity in the wetlands of the Qingtongxia reservoir can be based on rational planning of the proportion of different land uses within the wetlands, reducing landscape fragmentation by limiting human activities in the corresponding areas, as well as appropriate flow control measures. This study provides some reference for biodiversity conservation within wetlands.