Trophic cascades exist in a number of diverse ecosystems. They occur when the population of one organism changes, and thereby alters the dynamics of an entire food web. This short film features one such cascade, which has caused the rampant die-off of cordgrass in Cape Cod salt marshes. It follows the story of the “purple marsh crab”, Sesarma reticulatum, whose numbers have skyrocketed due to the removal of their predators. Along the way, we are reminded that our actions can have amplified and unforeseen consequences on ecosystems and organisms whom we may have never even encountered.
All of the illustrations and artwork in the video are original, and the music is used with permission from Oyster Boy (oysterboy.bandcamp.com). The images were photographed at the Brown University Science Center. Video originally appeared on CreatureCast.org. For more information about salt marsh ecology, visit bertnesslab.com/.
Special thanks to the Brown University Science Center, Casey Dunn, Natividad Chen, and the Bertness Lab at Brown University.