Anthropogenic disturbances caused declines in the wetland area and carbon pool in China during the last four decades

Wetlands are among the natural ecosystems with the highest soil carbon stocks on Earth. However, how anthropogenic disturbances have impacted the quantity and distribution of wetland carbon pool in China is not well understood. Here we used a comprehensive countrywide wetland inventory and Landsat 8 data to document the spatial patterns in China's wetland areas and carbon pools and to understand the underlying causes of their changes from the 1980s to 2010s. We found that the wetland area and carbon pool have decreased from 4.11 × 105 km2 and 15.2 Pg C in the 1980s to 2.14 × 105 km2 and 7.6 Pg C in the 2010s, respectively. Using the human influence index (HII) as a quantitative measure of anthropogenic disturbance intensity, we found a positive relationship between the HII values and wetland decreases in many regions and across China as a whole—which have increased 17% during the time period—indicating that anthropogenic disturbances have been a major factor causing wetland destruction in recent decades. This study provides new evidence for recent changes in China's wetland carbon pool and emphasizes the importance of mitigating anthropogenic disturbances for wetland conservation. We used the human influence index (HII) as a quantitative measure to evaluate the impacts of anthropogenic disturbance on wetlands in China in the last four decades. We found that both wetland area and carbon pool decreased from 4.11 × 105 km2 and 15.2 Pg C in the 1980s to 2.14 × 105 km2 and 7.6 Pg C in the 2010s, about 50% reduction. The positive relationship between the HII values—which have increased 17% during the time period—and wetland decreases in many regions across China indicates that anthropogenic disturbances have been a major factor causing wetland destruction in recent decades.