Comparing Salt Marsh Crab Effects across New England Reserves

Background

Salt marsh degradation and loss is accelerating in many regions. Multiple stressors are often responsible, sometimes including crab burrowing and herbivory. A recent national assessment identified stark differences in crab indicators between northern and southern New England, with the latter exhibiting intense signs of impacts by crabs. More details on crab patterns across the region were needed beyond the “broad-brush” assessment.

The Study

We used green crab traps, marsh platform burrow counts, and a new multi-metric index of relative crab abundance to examine patterns across the four National Estuarine Research Reserves in New England.

At the marshes examined, green crabs were very abundant in Maine, less abundant in New Hampshire, and intermediate in southern New England. Crab indicators from the multi-metric index and burrow counts were higher in southern New England marshes, but patterns from trapping were less clear.

Management Implications

This study confirmed that abundance and impacts by crabs vary dramatically between sites in northern and southern New England. This provides better context for managers and researchers when considering impacts to marshes from multiple crab species in salt marshes.

Collaborators

  • Narragansett Reserve (corresponding author)
  • Wells Reserve
  • University of the Virgin Islands
  • Waquoit Bay Reserve
  • Footprints in the Water LLC
  • USEPA National Health and Environmental Effects Research Laboratory

Product

"A comparative assessment of salt marsh crabs (Decapoda: Brachyura) across the National Estuarine Research Reserves in New England, USA"

Journal of Crustacean Biology, https://doi.org/10.1093/jcbiol/ruz083

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