Dynamic landscapes and the driving forces in the Yellow River Delta wetland region in the past four decades.

Wetlands provide a broad range of ecosystem services, such as flood control, groundwater replenishment, and water purification. These services are particularly important in the Yellow River Delta, one of four estuarine deltas in China. The aim of this study was to examine the patterns and drivers forces of wetland landscape in the Yellow River Delta. We analyzed the spatio-temporal characteristics of land use change and dynamic landscape patterns changes between 1980 and 2018, divided into eight periods, from land use and remote sensing data. We also analyzed data for annual precipitation, annual temperature, annual evapotranspiration, digital elevation, slope, distance from the main river, built-up land, GDP, and population with principal component analysis, to identify the main drivers behind the changes in the wetland landscape. The results showed that, from 1980 to 2018, the total area of wetland decreased first and then increased the total area of wetland increased and was 1172.73 km2 greater in 2018 than it was in 1980, and the types of wetland in the Yellow River Delta changed frequently. From 1980 to 2005, the area of wetland decreased and the landscape dominance and degree of fragmentation were relatively high. From 2006 to 2018, as environmental policies were implemented and wetland protection became more important, the rate of development of wetland areas increased in a north-south direction, the proportion of landscape types became more balanced, and the spatial distribution homogenized. The main drivers of change in the wetland landscapes were GDP, population, precipitation, and temperature which were included 81.852% of the original information. The findings from this study provide us with an improved understanding of how land use and wetland landscapes changed from 1980 and 2018 and may have implications for the protection of wetland ecosystems, species diversity, and sustainable development.