Driving forces of changes in China’s wetland area from the first (1999–2001) to second (2009–2011) National Inventory of Wetland Resources

Based on the wetland areas recorded in the First National Inventory of Wetland Resources (FNIWR; 1999–2001) and the Second National Inventory of Wetland Resources (SNIWR; 2009–2011), as well as regional environmental parameters including meteorological conditions and land-use structure, the driving forces of changes in China’s wetland area from the FNIWR to the SNIWR were investigated. The total area of China’s wetlands larger than 1 km2 decreased from 384.8 × 103 km2 in the FNIWR to 350.8 × 103 km2 in the SNIWR. Natural wetland areas, including marshes, rivers, lakes, and coastal wetlands, decreased by 33.8 × 103 km2 over the study period, accounting for 99.4% of the decrease in the wetland area. Regions with decreased marsh and reservoir wetland areas were located mainly in Central and Eastern China, and those with increased river and lake wetland areas were located in Western China. There were no significant regression coefficients between the percentages of change in marsh and lake wetland areas and environmental parameters. However, changes in river wetland areas were positively regressed with changes in forest areas, mean annual temperature, and extreme minimum temperature, and changes in reservoir wetland areas were positively regressed with changes in city construction areas and mean annual temperature. Therefore, it seems that increased forest area and regional temperature alleviated the degradation of river wetland areas, while increased city construction areas and regional temperature alleviated the degradation of reservoir areas.