Invasive Spartina alterniflora marshes in China: a blue carbon sink at the expense of other ecosystem services

Abstract

Coastal (marine) wetlands are recognized as one of the world's most efficient sinks for organic carbon (“blue carbon”), and credits for their restoration and conservation can be obtained from carbon markets. We reviewed 50 studies to compare the climate mitigation potential of the invasive cordgrass Spartina alterniflora to that of native vegetation in marshes along the coast of China. The importance of S alterniflora marshes as a carbon sink varied geographically; however, at all sites soils associated with S alterniflora emitted substantially more methane than soils populated with native plants. Because the species was deliberately introduced, the carbon stored in S alterniflora marshes could qualify for inclusion within China's national inventory of greenhouse‐gas emissions. However, in locations where it significantly increases carbon stocks, its dominance results in the loss of other ecosystem services. Therefore, if included in a national inventory, S alterniflora marshes could conflict with China's action plan for meeting UN Sustainable Development Goals.