Document Type
Article
Department/Program
Virginia Institute of Marine Science
Publication Date
2019
Journal
Earth Surface Processes and Landforms
Volume
44
First Page
944
Last Page
952
Abstract
Vegetation is a critical component of the ecogeomorphic feedbacks that allow a salt marsh to build soil and accrete vertically. Vegetation dieback can therefore have detrimental effects on marsh stability, especially under conditions of rising sea levels. Here, we report a variety of sediment transport measurements associated with an unexpected, natural dieback in a rapidly prograding marsh in the Altamaha River Estuary, Georgia. We find that vegetation mortality led to a significant loss in elevation at the dieback site as evidenced by measurements of vertical accretion, erosion, and surface topography compared to vegetated refer- ence areas. Below-ground vegetation mortality led to reduced soil shear strength. The dieback site displayed an erosional, concave-up topographic profile, in contrast to the reference sites. At the location directly impacted by the dieback, there was a reduction in flood dominance of suspended sediment concentration. Our work illustrates how a vegetation disturbance can at least temporarily reverse the local trajectory of a prograding marsh and produce complex patterns of sediment transport.
DOI
10.1002/esp.4547
Keywords
dieback; sediment transport; salt marsh; erosion; vegetation
Recommended Citation
Coleman, Daniel J. and Kirwan, Matthew L., The effect of a small vegetation dieback event on salt marsh sediment transport (2019). Earth Surface Processes and Landforms, 44, 944-952.
10.1002/esp.4547