Rapid shoreward encroachment of salt marsh cordgrass in response to accelerated sea-level rise

Citation
Jp. Donnelly et Md. Bertness, Rapid shoreward encroachment of salt marsh cordgrass in response to accelerated sea-level rise, P NAS US, 98(25), 2001, pp. 14218-14223
Citations number
27
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Multidisciplinary
Journal title
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
ISSN journal
0027-8424 → ACNP
Volume
98
Issue
25
Year of publication
2001
Pages
14218 - 14223
Database
ISI
SICI code
0027-8424(200112)98:25<14218:RSEOSM>2.0.ZU;2-F
Abstract
The distribution of New England salt marsh communities is intrinsically lin ked to the magnitude, frequency, and duration of tidal inundation. Cordgras s (Spartina alterniflora) exclusively inhabits the frequently flooded lower elevations, whereas a mosaic of marsh hay (Spartina patens), spike grass ( Distichlis spicata), and black rush (Juncus gerardi) typically dominate hig her elevations. Monitoring plant zonal boundaries in two New England salt m arshes revealed that low-marsh cordgrass rapidly moved landward at the expe nse of higher-marsh species between 1995 and 1998. Plant macrofossils from sediment cores across modern plant community boundaries provided a 2,500-ye ar record of marsh community composition and documented the migration of co rdgrass into the high marsh. Isotopic dating revealed that the initiation o f cordgrass migration occurred in the late 19th century and continued throu gh the 20th century. The timing of the initiation of cordgrass migration is coincident with an acceleration in the rate of sea-level rise recorded by the New York tide gauge. These results suggest that increased flooding asso ciated with accelerating rates of sea-level rise has stressed high-marsh co mmunities and promoted landward migration of cordgrass. If current rates of sea-level rise continue or increase slightly over the next century, New En gland salt marshes will be dominated by cordgrass. If climate warming cause s sea-level rise rates to increase significantly over the next century, the se cordgrass-dominated marshes will likely drown, resulting in extensive lo sses of coastal wetlands.