Keystone predators govern the pathway and pace of climate impacts in a subarctic marine ecosystem

Predator loss and climate change are hallmarks of the Anthropocene yet their interactive effects are largely unknown. Here, we show that massive calcareous reefs, built slowly by the alga Clathromorphum nereostratum over centuries to millennia, are now declining because of the emerging interplay between these two processes. Such reefs, the structural base of Aleutian kelp forests, are rapidly eroding because of overgrazing by herbivores. Historical reconstructions and experiments reveal that overgrazing was initiated by the loss of sea otters, Enhydra lutris (which gave rise to herbivores capable of causing bioerosion), and then accelerated with ocean warming and acidification (which increased per capita lethal grazing by 34 to 60% compared with preindustrial times). Thus, keystone predators can mediate the ways in which climate effects emerge in nature and the pace with which they alter ecosystems.

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Cascading social-ecological costs and benefits triggered by a recovering keystone predator

Science ◽

10.1126/science.aay5342 ◽

2020 ◽

Vol 368 (6496) ◽

pp. 1243-1247 ◽

Cited By ~ 3

Author(s):

Edward J. Gregr ◽

Villy Christensen ◽

Linda Nichol ◽

Rebecca G. Martone ◽

Russell W. Markel ◽

...

Keyword(s):

Ecosystem Services ◽

Grazing Pressure ◽

Economic Consequences ◽

Ecosystem Change ◽

Kelp Forests ◽

Sea Otter ◽

Sea Otters ◽

Ecological Benefits ◽

Social Ecological ◽

Keystone Predators

Predator recovery often leads to ecosystem change that can trigger conflicts with more recently established human activities. In the eastern North Pacific, recovering sea otters are transforming coastal systems by reducing populations of benthic invertebrates and releasing kelp forests from grazing pressure. These changes threaten established shellfish fisheries and modify a variety of other ecosystem services. The diverse social and economic consequences of this trophic cascade are unknown, particularly across large regions. We developed and applied a trophic model to predict these impacts on four ecosystem services. Results suggest that sea otter presence yields 37% more total ecosystem biomass annually, increasing the value of finfish [+9.4 million Canadian dollars (CA$)], carbon sequestration (+2.2 million CA$), and ecotourism (+42.0 million CA$). To the extent that these benefits are realized, they will exceed the annual loss to invertebrate fisheries (−$7.3 million CA$). Recovery of keystone predators thus not only restores ecosystems but can also affect a range of social, economic, and ecological benefits for associated communities.

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Faculty Opinions recommendation of Keystone predators govern the pathway and pace of climate impacts in a subarctic marine ecosystem.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.738649793.793578502 ◽

2020 ◽

Author(s):

Mark Hay

Keyword(s):

Marine Ecosystem ◽

Climate Impacts ◽

Keystone Predators

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Causes and consequences of marine mammal population declines in southwest Alaska: a food-web perspective

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2008.0231 ◽

2009 ◽

Vol 364 (1524) ◽

pp. 1647-1658 ◽

Cited By ~ 43

Author(s):

J.A. Estes ◽

D.F. Doak ◽

A.M. Springer ◽

T.M. Williams

Keyword(s):

World War Ii ◽

Marine Mammal ◽

Marine Mammals ◽

Marine Ecosystem ◽

Kelp Forests ◽

Sea Otter ◽

Population Declines ◽

Killer Whales ◽

Sea Otters ◽

Coastal Marine

Populations of sea otters, seals and sea lions have collapsed across much of southwest Alaska over the past several decades. The sea otter decline set off a trophic cascade in which the coastal marine ecosystem underwent a phase shift from kelp forests to deforested sea urchin barrens. This interaction in turn affected the distribution, abundance and productivity of numerous other species. Ecological consequences of the pinniped declines are largely unknown. Increased predation by transient (marine mammal-eating) killer whales probably caused the sea otter declines and may have caused the pinniped declines as well. Springer et al . proposed that killer whales, which purportedly fed extensively on great whales, expanded their diets to include a higher percentage of sea otters and pinnipeds following a sharp reduction in great whale numbers from post World War II industrial whaling. Critics of this hypothesis claim that great whales are not now and probably never were an important nutritional resource for killer whales. We used demographic/energetic analyses to evaluate whether or not a predator–prey system involving killer whales and the smaller marine mammals would be sustainable without some nutritional contribution from the great whales. Our results indicate that while such a system is possible, it could only exist under a narrow range of extreme conditions and is therefore highly unlikely.

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Faculty Opinions recommendation of Keystone predators govern the pathway and pace of climate impacts in a subarctic marine ecosystem.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.738649793.793584770 ◽

2021 ◽

Author(s):

Tim Newbold ◽

Silvia Ceausu ◽

Charlotte Outhwaite

Keyword(s):

Marine Ecosystem ◽

Climate Impacts ◽

Keystone Predators

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Novel infections of Corynosoma enhydri and Profilicollis sp. (Acanthocephala: Polymorphidae) identified in sea otters Enhydra lutris

Diseases of Aquatic Organisms ◽

10.3354/dao03442 ◽

2020 ◽

Vol 137 (3) ◽

pp. 239-246 ◽

Cited By ~ 1

Author(s):

KM Shanebeck ◽

J Lakemeyer ◽

U Siebert ◽

K Lehnert

Keyword(s):

Enhydra Lutris ◽

Sea Otters

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Predicting Oil Spill Impacts on Southern Sea Otters (Enhydra Lutris Nereis)

10.31979/etd.f4a8-ftem ◽

2014 ◽

Author(s):

Emily Ann Golson

Keyword(s):

Oil Spill ◽

Enhydra Lutris ◽

Sea Otters ◽

Enhydra Lutris Nereis

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The historical and contemporary status of the sea otter Enhydra lutris population on Urup Island, southern Kuril Islands

Oryx ◽

10.1017/s0030605320000812 ◽

2021 ◽

pp. 1-6

Author(s):

Igor Popov ◽

Alexey Scopin

Keyword(s):

Total Population ◽

Kuril Islands ◽

Sea Otter ◽

Enhydra Lutris ◽

Sea Otters ◽

The Past ◽

Remote Island ◽

Contemporary Status ◽

Wildlife Refuges ◽

Effective Conservation

Abstract We describe the population of the Еndangered sea otter Enhydra lutris on Urup Island, one of the main wildlife refuges in the southern Kuril Islands of Russia. We reviewed historical and local reports of the sea otter, identified its habitat around the island, and surveyed the coastal waters of the island in 2019. Sea otters were numerous on Urup Island in the past but were hunted excessively and almost exterminated by the 1950s. Since then, sea otter populations have increased, and as the island is almost uninhabited we expected otters to be numerous. This was not the case, and we estimated the total population to be 363 ± SE 126 individuals. Our observation of two skinned carcasses on the shore suggests the low numbers are a result of poaching for the illegal fur trade. The case of Urup Island demonstrates that sea otters require active conservation, as even on a remote island they remain threatened. Establishment of protected areas would be an effective conservation measure for this species, although the suppression of demand for sea otter fur is of the greatest importance.

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