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Trends in surface elevations of American Samoa mangroves


Gilman, Eric and Ellison, JC and Ierupaala, S and Tuaumu, S, Trends in surface elevations of American Samoa mangroves, Wetlands Ecology and Management, 15, (5) pp. 391-404. ISSN 0923-4861 (2007) [Refereed Article]

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DOI: doi:10.1007/s11273-007-9038-6


Rates of change in elevation of mangrove surfaces, determined from observations of changes in the height above the mangrove surface of stakes, generally inserted through the organic peat layer to reach consolidated substrate, were measured in one fringe and one basin mangrove wetland on Tutuila Island, American Samoa. Knowledge of trends in elevation change of coastal wetlands contributes to assessing vulnerability to projected relative sea level rise. The fringe and basin mangroves had rates of change in elevation of 0.6 mm yr1 (2.0) and 2.2 mm yr-1 (5.6), where a negative result means lowering in elevation. These trends were not statistically significant (P > 0.05) and the error intervals around the point estimates of trends in change in elevation overlap zero for both study sites, meaning that it is not clear if the mangrove surfaces have been lowering, rising or not changing. Despite the large error intervals, likely due to short-term variability and cyclical patterns in sedimentation, results indicate that the fringe mangrove has been experiencing a rise in sea level relative to the mangrove surface as the relative sea level rise rate (+1.65 to +2.29 mm yr1) has been exceeding the rate of change in elevation of the mangrove surface (2.6 to +1.4 mm yr1). It is unclear if the basin mangrove has been experiencing a rise in sea level relative to the mangrove surface. If upper projections for accelerated relative sea level rise in American Samoa occur over coming decades, American Samoa mangroves will migrate landward, where unobstructed, as a natural response to relative sea level rise

Item Details

Item Type:Refereed Article
Research Division:Earth Sciences
Research Group:Physical geography and environmental geoscience
Research Field:Physical geography and environmental geoscience not elsewhere classified
Objective Division:Environmental Management
Objective Group:Coastal and estuarine systems and management
Objective Field:Measurement and assessment of estuarine water quality
UTAS Author:Gilman, Eric (Mr Eric Gilman)
UTAS Author:Ellison, JC (Associate Professor Joanna Ellison)
ID Code:50808
Year Published:2007
Deposited By:Geography and Environmental Studies
Deposited On:2007-08-01
Last Modified:2011-11-30
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