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

Science ◽  
2020 ◽  
Vol 368 (6496) ◽  
pp. 1243-1247 ◽  
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.

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

Science ◽  
2020 ◽  
Vol 369 (6509) ◽  
pp. 1351-1354 ◽  
Author(s):  
Douglas B. Rasher ◽  
Robert S. Steneck ◽  
Jochen Halfar ◽  
Kristy J. Kroeker ◽  
Justin B. Ries ◽  
...  
Keyword(s):  
Marine Ecosystem ◽  
Climate Impacts ◽  
Interactive Effects ◽  
Kelp Forests ◽  
Enhydra Lutris ◽  
Sea Otters ◽  
Historical Reconstructions ◽  
Per Capita ◽  
Structural Base ◽  
Keystone Predators

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.

The dynamics and geographic disjunction of the kelp Eisenia arborea along the west coast of Canada

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Jane C. Watson ◽  
Michael W. Hawkes ◽  
Lynn C. Lee ◽  
Andy Lamb
Keyword(s):  
North America ◽  
West Coast ◽  
Vancouver Island ◽  
Grazing Pressure ◽  
Disjunct Distribution ◽  
Kelp Forests ◽  
The West ◽  
Sea Otters ◽  
Eisenia Arborea ◽  
Ne Pacific

Abstract Eisenia arborea has a disjunct distribution along the west coast of North America. We detail the current distribution of E. arborea and use long-term records to examine how present-day shifts in E. arborea prevalence and abundance in British Columbia (BC), relative to the dominant stipitate kelp Pterygophora californica, may be driven by interactions between changing grazing pressure and warming water. We further speculate on how the disjunction of E. arborea arose. The ancestor of E. arborea likely dispersed from Japan to North America where glaciation disrupted its distribution and speciation occurred. As glaciers retreated E. arborea likely dispersed into BC from warmer waters in the south and/or expanded from refugia off Vancouver Island and Haida Gwaii. While E. arborea is uncommon, our records extend its range into Alaska and Washington State. Along western Vancouver Island, BC, under warming conditions, E. arborea prevalence and abundance increased where once-extirpated sea otters (Enhydra lutris) removed urchins. Where otters were absent, however, reduced summer wave heights, associated with warming, apparently allowed urchins to graze shallow-water kelps, which declined. We suggest that under warming conditions, sea otters may increase kelp resilience, with E. arborea becoming more prevalent in NE Pacific kelp forests.

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

2009 ◽  
Vol 364 (1524) ◽  
pp. 1647-1658 ◽  
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.

scholarly journals Archaeological and Contemporary Evidence Indicates Low Sea Otter Prevalence on the Pacific Northwest Coast During the Late Holocene

Ecosystems ◽  
2021 ◽  
Author(s):  
Erin Slade ◽  
Iain McKechnie ◽  
Anne K. Salomon
Keyword(s):  
Pacific Northwest ◽  
Carrying Capacity ◽  
Late Holocene ◽  
Northwest Coast ◽  
Sea Otter ◽  
Size Distributions ◽  
Sea Otters ◽  
Pacific Northwest Coast ◽  
Social Ecological ◽  
The Pacific

AbstractThe historic extirpation and subsequent recovery of sea otters (Enhydra lutris) have profoundly changed coastal social-ecological systems across the northeastern Pacific. Today, the conservation status of sea otters is informed by estimates of population carrying capacity or growth rates independent of human impacts. However, archaeological and ethnographic evidence suggests that for millennia, complex hunting and management protocols by Indigenous communities limited sea otter abundance near human settlements to reduce the negative impacts of this keystone predator on shared shellfish prey. To assess relative sea otter prevalence in the Holocene, we compared the size structure of ancient California mussels (Mytilus californianus) from six archaeological sites in two regions on the Pacific Northwest Coast, to modern California mussels at locations with and without sea otters. We also quantified modern mussel size distributions from eight locations on the Central Coast of British Columbia, Canada, varying in sea otter occupation time. Comparisons of mussel size spectra revealed that ancient mussel size distributions are consistently more similar to modern size distributions at locations with a prolonged absence of sea otters. This indicates that late Holocene sea otters were maintained well below carrying capacity near human settlements as a result of human intervention. These findings illuminate the conditions under which sea otters and humans persisted over millennia prior to the Pacific maritime fur trade and raise important questions about contemporary conservation objectives for an iconic marine mammal and the social-ecological system in which it is embedded.

Characterizing the impact of recovering sea otters on commercially important crabs in California estuaries

2020 ◽  
Vol 655 ◽  
pp. 123-137
Author(s):  
TM Grimes ◽  
MT Tinker ◽  
BB Hughes ◽  
KE Boyer ◽  
L Needles ◽  
...  
Keyword(s):  
Abiotic Factors ◽  
Sea Otter ◽  
Dungeness Crab ◽  
Sea Otters ◽  
Elkhorn Slough ◽  
Enhydra Lutris Nereis ◽  
Crab Abundance ◽  
Population Sizes ◽  
Commercially Important ◽  
The Impact

Protective legislation and management have led to an increase in California’s sea otter Enhydra lutris nereis population. While sea otter recovery has been linked to ecosystem benefits, sea otter predation may negatively affect commercially valuable species. Understanding the potential influence of sea otters is of particular importance as their range expands into estuaries that function as nurseries for commercially valuable species like Dungeness crab Metacarcinus magister. We consider how sea otter predation has affected the abundance and size of juvenile Dungeness crab in Elkhorn Slough, California, USA, and analyzed cancrid crab abundance and size across 4 California estuaries with and without sea otters to understand how biotic and abiotic factors contribute to observed variation in crab size and abundance. We compared trends in southern sea otters relative to Dungeness crab landings in California to assess whether increasing sea otter abundance have negatively impacted landings. In Elkhorn Slough, juvenile Dungeness crab abundance and size have declined since 2012, coinciding with sea otter population growth. However, the impact of sea otters on juvenile Dungeness crab size was habitat-specific and only significant in unvegetated habitat. Across estuaries, we found that cancrid crab abundance and size were negatively associated with sea otter presence. While abiotic factors varied among estuaries, these factors explained little of the observed variation in crab abundance or size. Although we found evidence that sea otters can have localized effects on cancrid crab populations within estuaries, we found no evidence that southern sea otters, at recent population sizes, have negatively impacted Dungeness crab landings in California from 2000-2014.

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

Oryx ◽  
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.

scholarly journals “A Very Noble Crop”: Financial Stability, Agronomic Expertise, and Personal Values Support Conservation in Shade-Grown Coffee Farms

2021 ◽  
Vol 13 (13) ◽  
pp. 7227
Author(s):  
Jeannine H. Richards ◽  
Ingrid M. Torrez Luna ◽  
Alberto Vargas
Keyword(s):  
Ecosystem Services ◽  
Financial Stability ◽  
Personal Values ◽  
Nutrient Cycles ◽  
Tropical Biodiversity ◽  
Social Ecological ◽  
Positive Attitudes ◽  
Building Conservation ◽  
Aesthetic Values ◽  
Conservation Interventions

Shade-grown coffee is an important reservoir for tropical biodiversity, but habitat quality hinges on decisions made by farmers. Our research aims to investigate the link between coffee producers’ decisions and outcomes for biodiversity, using epiphytes as our focal group. Using qualitative methods, we interviewed 33 producers in northern Nicaragua to understand how they connect trees and epiphytes on their farms to ecosystem services and how personal values, access to agronomic expertise, labor supply, and financial stability influence decision-making. We used interview responses to construct six producer typologies. Most producers had strong positive attitudes toward trees and associated them with a variety of important ecosystem services. Smallholders were more likely to connect trees with provisioning services, while producers on larger farms and with greater agronomic knowledge emphasized regulating services. Most producers connected epiphytes primarily with aesthetic values. Across demographics, producers emphasized the restorative potential for shade coffee in repairing damage to soil, water, and nutrient cycles caused by other forms of agriculture. The conservation significance and sustainability of this social-ecological system can be maintained and expanded through economic and capacity-building conservation interventions, especially when those can be connected to values already held by farmers.

Multi-level social-ecological networks in a payments for ecosystem services programme in central Veracruz, Mexico

2020 ◽  
pp. 1-7
Author(s):  
Alfonso Langle-Flores ◽  
Adriana Aguilar Rodríguez ◽  
Humberto Romero-Uribe ◽  
Julia Ros-Cuéllar ◽  
Juan José Von Thaden
Keyword(s):  
Ecosystem Services ◽  
Spatial Scales ◽  
Payments For Ecosystem Services ◽  
Collaboration Network ◽  
Governmental Organizations ◽  
Social Ecological ◽  
Non Governmental Organizations ◽  
Conservation Activity ◽  
Ecological Importance ◽  
Hydrological Services

Summary Payments for ecosystem services (PES) programmes have been considered an important conservation mechanism to avoid deforestation. These environmental policies act in social and ecological contexts at different spatial scales. We evaluated the social-ecological fit between stakeholders and ecosystem processes in a local PES programme across three levels: social, ecological and social-ecological. We explored collaboration among stakeholders, assessed connectivity between forest units and evaluated conservation activity links between stakeholders and forest units. In addition, to increase programme effectiveness, we classified forest units based on their social and ecological importance. Our main findings suggest that non-governmental organizations occupy brokerage positions between landowners and government in a dense collaboration network. We also found a partial spatial misfit between conservation activity links and the forest units that provide the most hydrological services to Xalapa. We conclude that conservation efforts should be directed towards the middle and high part of the Pixquiac sub-watershed and that the role of non-governmental organizations as mediators should be strengthened to increase the efficiency and effectiveness of the local PES programme.

scholarly journals Valuation of kelp forest ecosystem services in the Falkland Islands: A case study integrating blue carbon sequestration potential

One Ecosystem ◽  
2021 ◽  
Vol 6 ◽  
Author(s):  
Daniel Bayley ◽  
Paul Brickle ◽  
Paul Brewin ◽  
Neil Golding ◽  
Tara Pelembe
Keyword(s):  
Ecosystem Services ◽  
Kelp Forest ◽  
Blue Carbon ◽  
Falkland Islands ◽  
Kelp Forests ◽  
Storm Damage ◽  
Ecological Processes ◽  
True Value ◽  
Sequestration Potential

Kelp forests provide many important ecosystem services to people, including mitigating storm damage, cycling nutrients, and providing commercially-harvestable resources. However, kelp forests’ ability to sequester carbon dioxide, and therefore help regulate the climate, has until recently, been overlooked in assessments of the beneficial services they provide. In this study we incorporate updated knowledge on the potential of kelp to sequester ‘blue carbon’, and use the extensive kelp forests of the Falkland Islands as a case study to assess the value of kelp forest to society through multiple associated ecosystem services. Our analysis shows kelp forests provide a highly valuable range of direct and indirect services, which if managed correctly, will continue to benefit people, both now and in the future. The total estimated value of the Falkland Islands’ kelp system is currently equivalent to ~ £2.69 billion per year (or £3.24 million km-2 year-1). However, the true value of the kelp forest surrounding the Falkland Islands is likely to be higher still, given that our estimate does not account for elements such as associated scientific research, tourism, and cultural services, due to the necessary data currently being unavailable. Similarly, the full value of these highly biodiverse ecosystems in supplying habitat and food to a large range of associated species is crucial, yet extremely difficult to fully quantify. This study illustrates the importance of maintaining kelp ecosystems in a healthy state to ensure they continue to supply valuable ecological processes, functional roles, and ecosystem services, including their overlooked role as significant long-term carbon sinks.

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