Cascading Effects of Predator Recovery on Coupled Human-Ocean Ecosystems
The depletion of predators in the world’s ecosystems is one of humankind’s most pervasive influences on nature. In addition to triggering a cascade of effects across food webs, the reduction of predators can transform ecosystems into fundamentally different states, altering the processes and resources upon which humans depend. With the recovery of previously exploited predators, tipping points can be breached, and surprising shifts can ensue.
Along North America’s high-latitude coastlines, sea otters were once eliminated from parts of their habitat range during the 18th- and 19th-century fur trade. Their subsequent recovery has caused remarkable changes to marine systems, generating shifts in kelp forest ecosystems, coastal economies, and cultures. These keystone predators can cause ecosystems to flip between alternating states. When sea otters are absent, their invertebrate prey, such as crabs, clams, abalone, and sea urchins, can flourish. When otters are present, these commercially and culturally valuable shellfish are dramatically reduced, but kelp beds thrive, providing valuable habitat and an additional source of food that, in some cases, allows for the expansion of other fisheries. Consequently, sea otter recovery can create complex ecological and social trade-offs. Among coastal communities, conflicts may arise because of the economic and cultural loss associated with reduced fishing opportunities for invertebrates, as well as concerns about food security, food sovereignty, and rights of the First Nations - the indigenous people of Canada which have lived on the coast for over 12,000 years.
In partnership with British Columbia's coastal First Nations and the Hakai Beach Institute, Anne Salomon’s Pew Fellows project will research prehistoric kelp forest ecosystems, synthesize data on sea otter-induced impacts, and document the evolution of social and cultural values associated with this predator’s recovery. Working groups will bring together marine ecologists, archaeologists, and social scientists, along with First Nations managers and knowledge holders from areas of Alaska and British Columbia that are experiencing various stages of sea otter population recovery. Participants will share ideas on Western and traditional ecosystem-based management and develop alternative strategies that address the effects of sea otter predation on coastal fisheries. Salomon and her partners will then discuss their results with tribal councils, provincial and federal policymakers, nongovernmental organizations, and the public through a First Nations touring art exhibit and multimedia interactive photo-journal, aiming to implement these experimental ecosystem-based management policies.