Modeling the wetland restorability based on natural and anthropogenic impacts in Sanjiang Plain, China

Wetlands are reducing dramatically due to rapid agricultural occupation and urbanization, resulting in severe ecosystem degradation and environmental deterioration. Comprehensive wetland restoration planning that fully considers ecosystem-level processes has the potential to improve restoration efficiency and regional sustainability. Most evaluating criteria of restorability are confined to the natural impacts on the suitability of successful wetland restoration. However, anthropogenic impacts received little attention; especially in areas where most wetlands had been encroached by intensively used farmlands. Utilization intensity is also an important factor that influences the restorability of wetlands. Here, we propose a GIS-based Restorability Index (RESI) model to evaluate the wetland restorability of the Sanjiang Plain, which is the largest marsh area of China as well as the largest grain production base. In the first step, eight criteria including natural conditions (stream order, overland flow length, saturation index, and soil characteristics) and anthropogenic impacts (land use, reclamation history, density of grain yield, and power density of agricultural machinery) were selected as influence factors of wetland restoration. For the second step, the RESI value was calculated for each grid cell via integration of spatially quantified criteria and these RESI values were classified into five levels to prioritize wetland restoration implementation. Finally, we designed a restoration plan according to the results of our restorability analysis and the requirements of regional sustainable development. This model offers a valuable tool for priority ranking of wetland restoration implementations in the agricultural landscape in a spatially explicit way.