Location: Exotic and Invasive Weeds ResearchTitle: Native plant restoration combats environmental change: development of carbon and nitrogen sequestration capacity using small cordgrass in European salt marshes Author
Submitted to: Environmental Monitoring and Assessment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/26/2013
Publication Date: 4/17/2013
Citation: Curado, G., Rubio-Casai, A., Figueroa, E., Grewell, B.J., Castillo, J.M. 2013. Native plant restoration combats environmental change: development of carbon and nitrogen sequestration capacity using small cordgrass in European salt marshes. Environmental Monitoring and Assessment. 185:8439-8449. DOI 10.1007/s10661-013-3185-4. Interpretive Summary: Coastal salt marshes are greatly affected by increasing anthropogenic influences including exotic weed invasions, climate change, sea level rise, and increased eutrophication. An important function of estuarine wetlands is sequestration of carbon (C). Estuarine have been shown to sequester C at a rate more than ten times higher per unit area that any other wetland ecosystem due to high soil C-content and constant burial due to sea level rise. We investigated the carbon sequestration capacity of a salt marsh in Spain in which native Spartina maritima (Small Cordgrass) was planted to replace South American Spartina densiflora that had been eradicated from the site. Since S. maritima is effective in uptake of atmospheric CO2, and at the same time counteracting salt marsh sinking provoked by sea level rise, restoration of European salt marshes using small cordgrass could potentially enhance the sequestration capacity of the marshes. This research demonstrates that biomass production and accumulation of S. maritima prairies established through restoration plantings following eradication of an invasive weed stabilizes sediments, and enhances the C- and N-sequestration capacity of the marshes. The restoration actions help retain the positive contribution of past cordgrass stands - the deep long-term storage of C in deep sediments, while the newly established S. maritima community replaces an exotic invader in the important C storage cycle.
Technical Abstract: Restoration of salt marshes is critical in the context of climate change and eutrophication of coastal waters, because their vegetation and sediments may act as carbon and nitrogen sinks. Our primary objectives were to quantify carbon (C) and nitrogen (N) stocks and sequestration rates in restored marshes dominated by Spartina maritima to provide support for restoration and management strategies that may offset negative aspects of eutrophication and climate change in estuarine ecosystems. Sediment C-content was between ca. 13 mg C g-1 and sediment nitrogen-content was ca. 1.8 mg N g-1. S. maritima concentrated more C in leaves and stems than in roots. S. maritima also concentrated more N in its leaves than in the other organs. C-stock in the restored marshes was 29.6 t C ha-1; ca. 16% was stored in S. maritima tissues. N-stock was 3.6 t N ha-1, with 8.3% stored in S. maritima. Our results showed that 2.5 years after restoring the wetlands with S. maritima, the native cordgrass is sequestering atmospheric carbon, and providing some mitigation for global warming. The stands are also capturing nitrogen and reducing eutrophication. The concentrations of C and N contents in sediments, and cordgrass relative cover of 62%, and low below-ground biomass suggest restored marshes sequester significant stocks of C and N. Restoration plantings of S. maritima s in low elevation marshes have replaced bare sediments following eradication of invasive populations of exotic Spartina densiflora. This restoration effort has increased the C- and N-sequestration capacity of the marsh by increasing biomass production and accumulation of a native cordgrass.