Marsh erosion as a consequence of edge vegetation losses

Creek widening and marsh area reduction as a result of vegetation loss around Lt. Island area (Wellfleet) between 1970 and 2000.

The loss of creekbank marsh vegetation (S. alterniflora in most cases) results in erosion and subsequent widening/lengthening of tidal creeks and a reduction in marsh area click for enlarged photo.

In contrast, where edge vegetation has not been lost (i.e., marshes with no reported dieback), these changes are not evident - i.e., creek architecture and marsh area are very stable over long time periods. The one exception to this is where the width of tidal inlets have increased and bank undercutting (not plant loss) results in widening.

 

Shrinkage of a marsh island near West Dennis Beach between 1952 and 2005 (photos courtesy of Don Liptak, NRCS, Barnstable and MassGIS).

 

<click for enlarged version of photo above>

 

Changes in the Swan River (Dennis) - a place where edge vegetation losses have been extensive -  over time.  This changes have occurred in the absence of any alterations in the tidal inlet width.

 

<click for enlarged version of photo above>

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