Brackish Marsh Plant Community Responses to Regional Precipitation and Relative sea-Level Rise

• Published in: Wetlands (Wilmington, N.C.) Vol. 36; no. 4; pp. 607 - 619
• Main Authors: Jarrell, Elizabeth R., Kolker, Alexander S., Campbell, Cassandra, Blum, Michael J.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.08.2016; Springer Nature B.V
• Subjects: Archives & records; Biomedical and Life Sciences; Brackish ecosystems; Cladium jamaicense; Climate; Climate change; Coastal ecosystems; Coastal Sciences; Coastal structures; Coasts; Cores; Ecology; Ecosystems; Environmental changes; Environmental conditions; Environmental Management; Freshwater & Marine Ecology; Geochronology; Hydrogeology; Landscape Ecology; Lead isotopes; Life Sciences; Marine; Marshes; Multiple regression analysis; Net losses; Original Research; Plant communities; Precipitation; Regional development; Saline environments; Salinity; Schoenoplectus americanus; Sea level; Sea level rise; Sediments; Seeds; Soil erosion; Structure-function relationships; Urban development; Wetlands; North Carolina; Pamlico Sound; United States > US; ANW, USA, North Carolina; ANW, USA, North Carolina, Pamlico Sound; Climate change; Coastal wetlands; Accretion rate
• DOI: 10.1007/s13157-016-0769-0
• ISSN: 0277-5212

Climate-driven shifts in environmental conditions can transform the structure and function of coastal ecosystems. Here we examine how two back-barrier brackish marshes in Pamlico Sound (North Carolina, USA) responded to changes in precipitation, temperature, and relative sea level and whether local rates of accretion have kept pace with relative sea-level rise. We used the distribution of seeds in sediment cores, coupled with 210 Pb-sediment geochronology, to determine patterns of community and ecosystem change over the past century. The chronologies demonstrate that both marshes recently transitioned from communities dominated by Cladium jamaicense , which prefers fresh and brackish settings, to communities dominated by Schoenoplectus americanus , which prefers brackish and saline environments. Multiple regression analysis indicates that community shifts are best explained by relative sea-level rise and regional trends in precipitation. Results also indicate that the marshes are developing an elevation deficit with respect to rising sea level, which likely influenced the conversion from C. jamaicense dominated to S. americanus dominated communities. These findings substantiate a growing body of evidence indicating that climate-driven shifts in environmental conditions are transforming coastal ecosystems and suggest that brackish intertidal marshes may become increasingly threatened by accelerated sea-level rise and associated environmental changes expected to unfold this century.