Abstract:
The climate change-induced expansion of mangroves into salt marshes could significantly alter the carbon (C) storage capacity of coastal wetlands, which have the highest average C storage per land area among unmanaged terrestrial ecosystems. Mangrove range expansion is occurring globally, but little is known about how these rapid climate-driven shifts may alter ecosystem C storage. Here, we quantify current C stocks in ecotonal wetlands across gradients of marsh- to mangrove-dominance, and use unique chronological maps of vegetation cover to estimate C stock changes from 2003 to 2010 in a 567-km2 wildlife refuge in the mangrove-salt marsh ecotone. We report that over the 7-yr. period, total wetland C stocks increased 22 % due to mangrove encroachment into salt marshes. Newly established mangrove stands stored twice as much C on a per area basis as salt marsh primarily due to differences in aboveground biomass, and mangrove cover increased by 69 % during this short time interval. Wetland C storage within the wildlife refuge increased at a rate of 2.7 Mg C ha-1 yr.-1, more than doubling the naturally high coastal wetland C sequestration rates. Mangrove expansion could account for a globally significant increase of terrestrial C storage, which may exert a considerable negative feedback on warming.
Citation:
Doughty, Cheryl L., Langley, J. Adam, Walker, Wayne S., Feller, Ilka C., Schaub, Ronald, and Chapman, Samantha K. 2016. "Mangrove Range Expansion Rapidly Increases Coastal Wetland Carbon Storage."
Estuaries and Coasts. 39 (2):385–396.
https://doi.org/10.1007/s12237-015-9993-8