Distribution and disturbances of ditches across salt marshes of the Northeast U.S. with implications for management and restoration

Journal of Environmental Management
By: , and 

Metrics

1
Crossref references
Web analytics dashboard Metrics definitions

Links

Abstract

Effective management of valuable coastal systems, such as salt marshes requires an understanding of the complex stressors influencing their continued threat of drowning. However, efforts to determine the effects of one potential stressor, ditches, have produced diverging results complicating management efforts. Ditches (linear trenches dug to drain salt marshes for agriculture and mosquito control) alter salt marsh hydrology, but their effects on widescale marsh function and degradation are poorly understood. We created a dataset of visible ditches and summarized ditch densities (length of ditches over area) for salt marshes of the Northeast U.S. to evaluate ditching against vulnerability metrics, including elevation and the unvegetated to vegetated marsh ratio (UVVR). We identified a scale dependency in which the larger/coarser the spatial scale of analysis, the greater the fraction of ditched salt marshes. Scale dependence explains discrepancies between previously determined ditch indices. In terms of effects on marsh vulnerability, relative elevation was not influenced by visible ditch presence. Ditch densities affected UVVR, exhibiting a multiple threshold behavior. When present at low densities, ditches have little effect on ponding; yet as ditch densities increase, UVVR (i.e., ponding) increases. The relationship between ditching and UVVR reverses at the highest ditch densities, with ponding substantially decreasing. The multiple threshold vulnerability response of Northeast salt marshes to the hydrologic influences imposed by ditching suggests restoration strategies should consider the degree of ditching rather than simply ditching presence.

Study Area

Publication type Article
Publication Subtype Journal Article
Title Distribution and disturbances of ditches across salt marshes of the Northeast U.S. with implications for management and restoration
Series title Journal of Environmental Management
DOI 10.1016/j.jenvman.2025.124444
Volume 376
Year Published 2025
Language English
Publisher Elsevier
Contributing office(s) Woods Hole Coastal and Marine Science Center
Description 124444, 12 p.
Country United States
State Connecticut, Delaware, Maine, Maryland, Massachusetts, New Hampshire, New Jersey, New York, Pennsylvania, Rhode Island, Vermont, Virginia, West Virginia
Additional publication details