title: Marsh macrophyte responses to inundation anticipate impacts of sea-level rise and indicate ongoing drowning of North Carolina marshes.
abstract: In situ persistence of coastal marsh habitat as sea level rises depends on whether macrophytes induce compensatory accretion of the marsh surface. Experimental planters in two North Carolina marshes served to expose two dominant macrophyte species to six different elevations spanning 0.75 m (inundation durations 0.4-99 %).Spartina alternifloraandJuncus roemerianusexhibited similar responses-with production in planters suggesting initial increases and then demonstrating subsequent steep declines with increasing inundation, conforming to a segment of the ecophysiological parabola. Projecting inundation levels experienced by macrophytes in the planters onto adjacent marsh platforms revealed that neither species occupied elevations associated with increasing production. Declining macrophyte production with rising seas reduces both bioaccumulation of roots below-ground and baffle-induced sedimentation above-ground. By occupying only descending portions of the parabola, macrophytes in central North Carolina marshes are responding to rising water levels by progressive declines in production, ultimately leading to marsh drowning.
authors.affiliation: Coastal Resources Management, East Carolina University, Greenville, NC 27858 USA ; Institute of Marine Sciences, University of North Carolina at Chapel Hill, Morehead City, NC 28557 USA.
authors.forename: Christine M
authors.initials: CM
authors.lastname: Voss
authors.affiliation: Department of Biology, East Carolina University, Greenville, NC 27858 USA.
authors.forename: Robert R
authors.initials: RR
authors.lastname: Christian
authors.affiliation: Department of Biological Sciences and the Belle W. Baruch Institute for Marine and Coastal Sciences, University of South Carolina, Columbia, SC 29208 USA.
authors.forename: James T
authors.initials: JT
authors.lastname: Morris