Created mangrove wetlands store belowground carbon and surface elevation change enables them to adjust to sea-level rise
Virginia Institute of Marine Science
Mangrove wetlands provide ecosystem services for millions of people, most prominently by providing storm protection, food and fodder. Mangrove wetlands are also valuable ecosystems for promoting carbon (C) sequestration and storage. However, loss of mangrove wetlands and these ecosystem services are a global concern, prompting the restoration and creation of mangrove wetlands as a potential solution. Here, we investigate soil surface elevation change, and its components, in created mangrove wetlands over a 25 year developmental gradient. All created mangrove wetlands were exceeding current relative sea-level rise rates (2.6 mm yr(-1)), with surface elevation change of 4.2-11.0 mm yr(-1) compared with 1.5-7.2 mm yr(-1) for nearby reference mangroves. While mangrove wetlands store C persistently in roots/soils, storage capacity is most valuable if maintained with future sea-level rise. Through empirical modeling, we discovered that properly designed creation projects may not only yield enhanced C storage, but also can facilitate wetland persistence perennially under current rates of sea-level rise and, for most sites, for over a century with projected medium accelerations in sea-level rise (IPCC RCP 6.0). Only the fastest projected accelerations in sea-level rise (IPCC RCP 8.5) led to widespread submergence and potential loss of stored C for created mangrove wetlands before 2100.
CLIMATE-CHANGE MITIGATION; ECOSYSTEM DEVELOPMENT; COASTAL WETLANDS; KEEP PACE; FORESTS; ACCRETION; MARSHES; REHABILITATION; SEDIMENTATION; VULNERABILITY
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Funding for this research was provided by the U.S. Environmental Protection Agency, Gulf Ecology Division; U.S. Geological Survey, Climate and Land Use Change R&D Program; and U.S. Geological Survey, Environments Program. We thank Darren Johnson for conducting the statistical analysis, Josh Jones for assistance with SET installation, Gordon Anderson for providing comparative NAVD88 elevations from marsh-transitional mangrove wetland communities in Everglades National Park, and Kerrylee Rogers (University of Wollongong, Australia) for reviewing a previous version of this manuscript. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
Krauss, Ken W.; Cormier, Nicole; Osland, Michael J.; Kirwan, Matthew L.; Stagg, Camille L.; Nestlerode, Janet A.; Russell, Marc J.; From, Andrew S.; Spivak, Amanda C.; Dantin, Darrin D.; Harvey, James E.; and Almario, Alejandro E., Created mangrove wetlands store belowground carbon and surface elevation change enables them to adjust to sea-level rise (2017). SCIENTIFIC REPORTS, 7.