How do otters protect salt marshes from erosion? Shellfishly
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Sea otters in California prey on crabs, thereby inadvertently protecting the vegetation that holds creek banks together. Credit: David Hayes/Alamy
Sea otters are helping to keep the shores of a central Californian estuary from crumbling into the ocean. They act as erosion control by feasting on shore crabs — crustaceans whose burrowing and vegetation-munching habits contribute to unstable salt-marsh banks.
By the twentieth century, humans had hunted sea otters (Enhydra lutris) nearly to extinction for their fur. But conservation efforts have helped population sizes to increase, and otters are re-establishing themselves in their historical haunts, including in the salt marshes of Monterey Bay’s Elkhorn Slough. Moreover, in marsh creeks with high numbers of sea otters, erosion rates are lower than when there were fewer sea otters, researchers report today in Nature1.
“It’s remarkable when you think about it,” says Jane Watson, a community ecologist at Vancouver Island University in Nanaimo, Canada. “You can have a single animal, the sea otter, come in and through predation actually mitigate the effects of erosion.”
