Crabs put the pinch on marshlands -- Science Nation
Crabs put the pinch on marshlands
If you take a quick glance at the marsh next to Saquatucket Harbor in Harwich Port, Mass., you will notice right away that some of the grass is missing. The cordgrass there, and all around Cape Cod, has been slowly disappearing for decades. "The cordgrass that's being destroyed here is the foundation species that builds salt marshes," explains marine ecologist Mark Bertness of Brown University. With support from NSF, Bertness studies this critical ecosystem, which protects our coastal environment by nurturing a complex web of plants and animals, filtering nutrients, and serving as a critical storm barrier. Bertness says the marshes are being overrun by purple marsh crabs because their main predators, blue crab and finfish, are being overfished. So, the purple marsh crabs are free to gorge on healthy fields of cordgrass and, once done feeding, the crabs leave behind nothing but lumpy fields of mud.
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