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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Hydrology and Remote Sensing Laboratory » Research » Publications at this Location » Publication #320104

Title: Soil carbon in natural, cultivated, and restored depressional wetlands in the Mid-Atlantic Coastal Plain

Author
item FENSTERMACHER, D. - UNIVERSITY OF MARYLAND
item RABENHORST, M. - UNIVERSITY OF MARYLAND
item LANG, M.W. - UNIVERSITY OF MARYLAND
item McCarty, Gregory
item NEEDLEMAN, B.A. - UNIVERSITY OF MARYLAND

Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/22/2015
Publication Date: 3/1/2016
Citation: Fenstermacher, D., Rabenhorst, M., Lang, M., McCarty, G.W., Needleman, B. 2016. Carbon in natural, cultivated, and restored depressional wetlands in the Mid-Atlantic Coastal Plain. Journal of Environmental Quality. 45:743-750.

Interpretive Summary: Wetlands represent critical environments that have declined in abundance in the USA over the 200 years following European settlement, having decreased by over 50% nationally as well as within the Mid Atlantic Region. Recent efforts have been made regarding the conservation, restoration, and creation of wetlands because of their environmental benefits and the “no net loss of wetlands” policy. This Mid-Atlantic Regional (MIAR) study for the Wetlands Component of the U.S. Department of Agriculture Conservation Effects Assessment Project (CEAP) was conducted to evaluate the effectiveness of wetland conservation practices along the Mid-Atlantic Coastal Plain. This study examined 48 wetland sites in Delaware, Maryland, Virginia, and North Carolina under natural, prior converted cropland (i.e., historic wetlands), and 5-10 year post wetland restoration status. Soil samples were collected by methods adjusting for soil density to a depth of one meter and were analyzed for percent carbon. The natural wetlands were found to have significantly greater carbon stocks than prior converted croplands and restored wetlands. The restored and prior converted sites did not differ significantly, which could be the result of the methods used to restore the wetlands, and the relatively young age of the restored sites. Wetlands were either restored by plugging drainage structures, with minimal surface disturbance, or by scraping the surface (i.e., excavation) to increase hydroperiod. Sites restored with the scraping procedures had lower carbon stocks indicating that such restoration procedures can negatively impact carbon storage.

Technical Abstract: Aerial extent of wetland ecosystems have decreased dramatically since precolonial times due to the conversion of these areas for human use. Wetlands provide various ecosystem services, and conservation efforts are being made to restore wetlands and their functions, including soil carbon storage. This Mid-Atlantic Regional (MIAR) study for the Wetlands Component of the National U.S. Department of Agriculture Conservation Effects Assessment Project (CEAP) was conducted to evaluate the effectiveness of wetland conservation practices along the Mid-Atlantic Coastal Plain. This study examined 48 wetland sites in Delaware, Maryland, Virginia, and North Carolina under natural, prior converted cropland, and 5-10 years post wetland restoration states. The North Carolina sites mainly contained soils dominated by organic soil materials and therefore were analyzed separately from the rest of the sites which were primarily mineral soils. Soil samples were collected using the bulk density core method by horizon to a depth of one meter and were analyzed for percent carbon. The natural wetlands were found to have significantly greater carbon stocks (21.5 ± 5.2 kg C m-2) than prior converted croplands (7.95 ± 1.93 kg C m-2; p <0.01) and restored wetlands (4.82 ± 1.13 kg C m-2; p <0.001). The restored and prior converted sites did not differ significantly, which could be the result of the methods used to restore the wetlands, and the relatively young age of the restored sites. Wetlands were either restored by plugging drainage structures, with minimal surface disturbance, or by scraping the surface (i.e., excavation) to increase hydroperiod. Sites restored with the scraping technique had lower carbon stocks (2.70 ± 0.38 kg C m-2) than those restored by passive techniques (6.06 ± 1.50 kg C m-2; p=0.09). Therefore, techniques that involve excavation and scraping to restore hydrology, appear to negatively impact carbon storage as a wetland ecosystem service.