Rapid wetland expansion during European settlement and its implication for marsh survival under modern sediment delivery rates

Geology
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Abstract

Fluctuations in sea-level rise rates are thought to dominate the formation and evolution of coastal wetlands. Here we demonstrate a contrasting scenario in which land-use–related changes in sediment delivery rates drive the formation of expansive marshland, and vegetation feedbacks maintain their morphology despite recent sediment supply reduction. Stratigraphic analysis and radiocarbon dating in the Plum Island Estuary (Massachusetts, United States) suggest that salt marshes expanded rapidly during the eighteenth and nineteenth centuries due to increased rates of sediment delivery following deforestation associated with European settlement. Numerical modeling coupled with the stratigraphic observations suggests that existing marshland could survive, but not form under the low suspended sediment concentrations observed in the estuary today. These results suggest that many of the expansive marshes that characterize the modern North American coast are metastable relicts of high nineteenth century sediment delivery rates, and that recent observations of degradation may represent a slow return to pre-settlement marsh extent. In contrast to ecosystem management practices in which restoring pre-anthropogenic conditions is seen as a way to increase ecosystem services, our results suggest that widespread efforts to restore valuable coastal wetlands actually prevent some systems from returning to a natural state.

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Publication type Article
Publication Subtype Journal Article
Title Rapid wetland expansion during European settlement and its implication for marsh survival under modern sediment delivery rates
Series title Geology
DOI 10.1130/G31789.1
Volume 39
Issue 5
Year Published 2011
Language English
Publisher Geological Society of America
Contributing office(s) Patuxent Wildlife Research Center
Description 4 p.
First page 507
Last page 510
Country United States
State Massachusetts
Other Geospatial Plum Island Estuary
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