B048-0002
A National Assessment of Tidal Wetland Carbon Sequestration and GHG emissions with Implications for Land Management in the United States
Thursday, 10 December 2020
Poster
Camille LaFosse Stagg1, Eric Ward1, Colin Daniel2, Bronwyn Rayfield3, Lisamarie Windham-Myers4, Rachel Sleeter5, Benjamin M Sleeter6, Kevin D Kroeger7, Sheel Bansal8, Bergit Rose Uhran9, Victoria Woltz10, Jinxun Liu6, William H. Conner11, Richard H Day1, Karen Thorne12, Kevin M Buffington13, Scott F Jones14, Kimberly Wickland15, Helene Genet16, Meagan Eagle Eagle17, Ken Krauss1 and Zhiliang Zhu18, (1)U.S. Geological Survey, Wetland and Aquatic Research Center, Lafayette, LA, United States, (2)Apex Resource Management Solutions, Ottawa, Canada, (3)Apex Resource Management Solutions, Ottawa, ON, Canada, (4)U.S. Geological Survey, Water Mission Area, Menlo Park, CA, United States, (5)US Geological Survey, Water Resources Mission Area, Gig Harbor, WA, United States, (6)U.S. Geological Survey, Western Geographic Science Center, Menlo Park, CA, United States, (7)USGS, Woods Hole, MA, United States, (8)U.S. Geological Survey, Northern Prairie Wildlife Research Center, Jamestown, ND, United States, (9)U.S. Geological Survey, Land Change Science, Reston, VA, United States, (10)USGS Headquarters, Reston, United States, (11)Clemson University, Belle W. Baruch Institute of Coastal Ecology and Forest Science, Georgetown, SC, United States, (12)U.S. Geological Survey, Vallejo, CA, United States, (13)U.S. Geological Survey, Davis, CA, United States, (14)U.S. Geological Survey, Western Ecological Research Center, Davis, CA, United States, (15)US Geological Survey, Water Resources Mission Area, Boulder, CO, United States, (16)University of Alaska Fairbanks, Institute of Arctic Biology, Fairbanks, AK, United States, (17)USGS, Woods Hole Coastal and Marine Science Center, Woods Hole, MA, United States, (18)U.S. Geological Survey, Reston, VA, United States
Abstract:
Because of their ability to sequester carbon, tidal wetlands can serve as greenhouse gas (GHG) sinks. If managed properly, wetlands are a critical resource for climate adaptation and mitigation. The overall goal of this wetland assessment is to improve national capabilities to monitor and report on wetland change and effects on carbon sequestration and GHG emissions that will inform policies to mitigate climate change impacts. Specific objectives were to 1) assess baseline carbon sequestration and GHG emissions in tidal wetlands, 2) quantify impacts of current and future land use change on tidal wetland carbon cycling, and 3) inform land management activities to enhance carbon sequestration and reduce GHG emissions.
To date, we have developed a model of carbon cycling in tidal wetlands of the conterminous US (CONUS) that provides a baseline assessment of wetland carbon. We quantified historic and current impacts of land use change on tidal wetland carbon sequestration and GHG emissions using the Land Use and Carbon Scenario Simulator (LUCAS) model adapted to tidal wetland ecosystems. LUCAS uses site-level carbon cycle data in a stock and flow model to simulate carbon dynamics, nested within a state-and-transition simulation framework to predict land change using remotely-sensed land use and land cover (LULC) data. As a test case, we calibrated LUCAS for the tidal wetlands of the Mississippi River Alluvial Plain, using in-situ measurements of carbon pools and fluxes across 24 sites, covering a range of salinity and vegetation types from palustrine forests to estuarine emergent wetlands. We then assessed tidal wetland carbon sequestration under current conditions with static LULC and with historic LULC (1996-2016) changes. This modeling approach was then extended to assess the effects of land use change on tidal wetland carbon sequestration across CONUS.
Our results highlight that estimates of carbon sequestration are extremely sensitive to assumptions about the fate of soil carbon following the transition of tidal wetland to open water. These findings indicate that conservation and restoration of wetlands have the potential to significantly reduce GHG emissions, and that future research should focus on soil carbon fate and transport across the terrestrial-aquatic boundary.
