Simulation of spatial distribution of china potential wetland

Abstract

Knowing the spatial distribution of potential wetlands is vital for improving wetland mapping accuracy, understanding the spatial evolution of wetlands, and making policies for wetland conservation and restoration. Topographic characteristics are key factors for wetland distribution. We first separated natural sinks from false sinks in DEM data by using window filtering, which proved to be more accurate than threshold approaches. We then developed the China CLTI (climato-topographic index) by combining the past 50 years’ average precipitation and evaporation data in China. A statistical method which was based on the relationship of wetland spatial distribution and CLTI distribution, was used to simulate the spatial distribution of China potential wetlands, and proved to be efficient and practical. This approach was simpler than approaches requiring the parameterization and solution of complicated hydrological models. The maximum distribution of Chinese wetlands, which was developed based on the union of four Chinese wetland maps (1978, 1990, 2000 and 2008), was input as the model main parameter. The distribution of simulated Chinese potential wetlands is consistent with the investigation of Chinese wetlands. Compared with previous studies, our simulated potential wetland spatial distribution has finer spatial resolution and high accuracy. According to the simulation, there are potentially about 325000 square kilometers of marshes and 256800 square kilometers of water bodies in China, mainly distributed in the northwest (mainly in Tibet, Qinghai, and Xinjiang), northeast (mainly in Inner Mongolia, Heilongjiang and Jilin), the North China Plain and the Yangtze River Basin. This research laid a foundation for modeling wetlands changes across China by using dynamic climatic variables and land cover and land use.