Keystone interdependence: Sea otter responses to a prey surplus following the collapse of a rocky intertidal predator

Science Advances
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Abstract

The sea star Pisaster ochraceus and sea otters (Enhydra lutris) are two predators capable of shaping rocky intertidal and kelp forest community structure and functioning. In 2013, a sea star wasting event decimated populations of Pisaster along the west coast of North America. The collapse of this species in the rocky intertidal revealed an unexpected relationship between two keystone predators. In this study, we show how the loss of Pisaster along the Monterey Peninsula, CA, USA led to an increase in mussel (Mytilus californianus) size and expansion into lower tidal zones. Before the sea star wasting event, the local sea otter population fluctuated around a near equilibrium. However, in the absence of Pisaster, sea otters increased their dietary intake on mussels, which contributed in part to a local population-level rise. These results demonstrate how the loss of a keystone predator in one ecosystem may impart population-level changes to another.

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Publication type Article
Publication Subtype Journal Article
Title Keystone interdependence: Sea otter responses to a prey surplus following the collapse of a rocky intertidal predator
Series title Science Advances
DOI 10.1126/sciadv.adu1028
Volume 11
Issue 18
Publication Date April 30, 2025
Year Published 2025
Language English
Publisher AAAS
Contributing office(s) Western Ecological Research Center
Description eadu1028, 10 p.
Country United States
State California
City Big Sur, Monterey
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