Are Crabs Killing the Nation's Salt Marshes?

The National Estuarine Research Reserve System provides an ideal platform for evaluating the relative importance of different threats to US salt marshes, because vegetation is sampled across all marsh elevations and across many regions. Our recent investigation at 15 reserves revealed that at a local scale, near tidal creeks in 4/15 of the reserves, crabs appear to have a strong negative effect on plants. However, at a broader scale, elevation has a stronger effect on marshes, suggesting that sea level rise poses a greater threat than crab herbivory or burrowing, although the two threats interact: Crab effects are likely to increase as waters rise. These photographs illustrate the article “Pattern and scale: evaluating generalities in crab distributions and marsh dynamics from small plots to a national scale” by Kerstin Wasson, Kenneth Raposa, Monica Almeida, Kathryn Beheshti, Jeffrey A. Crooks, Anna Deck, Nikki Dix, Caitlin Garvey, Jason Goldstein, David Samuel Johnson, Scott Lerberg, Pamela Marcum, Christopher Peter, Brandon Puckett, Jenni Schmitt, Erik Smith, Kari St. Laurent, Katie Swanson, Megan Tyrrell, and Rachel Guy published in Ecology. https://doi.org/10.1002/ecy.2813