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Mychajliw AM, Adams AJ, Brown KC, Campbell BT, Hardesty-Moore M, Welch ZS, Page HM, Southon JR, Cooper SD, Alagona PS. Coupled social and ecological change drove the historical extinction of the California grizzly bear ( Ursus arctos californicus). Proc Biol Sci 2024; 291:20230921. [PMID: 38196370 PMCID: PMC10777157 DOI: 10.1098/rspb.2023.0921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 11/06/2023] [Indexed: 01/11/2024] Open
Abstract
Large carnivores (order Carnivora) are among the world's most threatened mammals due to a confluence of ecological and social forces that have unfolded over centuries. Combining specimens from natural history collections with documents from archival records, we reconstructed the factors surrounding the extinction of the California grizzly bear (Ursus arctos californicus), a once-abundant brown bear subspecies last seen in 1924. Historical documents portrayed California grizzlies as massive hypercarnivores that endangered public safety. Yet, morphological measurements on skulls and teeth generate smaller body size estimates in alignment with extant North American grizzly populations (approx. 200 kg). Stable isotope analysis (δ13C, δ15N) of pelts and bones (n = 57) revealed that grizzlies derived less than 10% of their nutrition from terrestrial animal sources and were therefore largely herbivorous for millennia prior to the first European arrival in this region in 1542. Later colonial land uses, beginning in 1769 with the Mission era, led grizzlies to moderately increase animal protein consumption (up to 26% of diet), but grizzlies still consumed far less livestock than otherwise claimed by contemporary accounts. We show how human activities can provoke short-term behavioural shifts, such as heightened levels of carnivory, that in turn can lead to exaggerated predation narratives and incentivize persecution, triggering rapid loss of an otherwise widespread and ecologically flexible animal.
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Affiliation(s)
- Alexis M. Mychajliw
- Department of Biology, Middlebury College, Middlebury, VT, USA
- Environmental Studies Program, Middlebury College, Middlebury, VT, USA
- La Brea Tar Pits & Museum, Los Angeles, CA, USA
| | - Andrea J. Adams
- Earth Research Institute, University of California, Santa Barbara, CA, USA
| | - Kevin C. Brown
- Environmental Studies Program, University of California, Santa Barbara, CA, USA
| | - Beau T. Campbell
- Dinosaur Institute, Natural History Museum of Los Angeles County, Los Angeles, CA, USA
| | - Molly Hardesty-Moore
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA, USA
| | - Zoë S. Welch
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA, USA
| | - Henry M. Page
- Marine Science Institute, University of California, Santa Barbara, CA, USA
| | - John R. Southon
- Department of Earth System Science, University of California, Irvine, CA, USA
| | - Scott D. Cooper
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA, USA
| | - Peter S. Alagona
- Environmental Studies Program, University of California, Santa Barbara, CA, USA
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2
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Henson LH, Service C, Stronen AV, Moody J, Housty W, Reece D, vonHoldt B, Darimont CT. Genetic evidence to inform management of rare genetic variants and gene flow: Balancing the conservation of the rare “Spirit bear” allele and population genetic diversity across a complex landscape. CONSERVATION SCIENCE AND PRACTICE 2022. [DOI: 10.1111/csp2.12769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Affiliation(s)
- Lauren H. Henson
- Department of Geography University of Victoria Victoria British Columbia Canada
- Raincoast Conservation Foundation Sidney British Columbia Canada
| | - Christina Service
- Kitasoo/Xai'xais Stewardship Authority Klemtu British Columbia Canada
| | - Astrid Vik Stronen
- Department of Biology University of Ljubljana Ljubljana Slovenia
- Department of Biotechnology and Life Sciences Insubria University Varese Italy
| | - Jason Moody
- Nuxalk Stewardship Office Bella Coola British Columbia Canada
| | - William Housty
- Heiltsuk Integrated Resource Management Department Bella Coola British Columbia Canada
| | - Donald Reece
- Gitga'at Oceans and Lands Department Hartley Bay British Columbia Canada
| | - Bridgett vonHoldt
- Department of Ecology and Evolutionary Biology Princeton University Princeton New Jersey USA
| | - Chris T. Darimont
- Department of Geography University of Victoria Victoria British Columbia Canada
- Raincoast Conservation Foundation Sidney British Columbia Canada
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3
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Shardlow TF, Van Elslander J, Mowat G. The influence of human disturbance on Pacific salmon ( Oncorhynchus spp.) in the diet of American black bears ( Ursus americanus) in two areas of coastal British Columbia, Canada. CAN J ZOOL 2022. [DOI: 10.1139/cjz-2021-0198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Recent studies have highlighted the importance of salmon (genus Oncorhynchus Suckley, 1861) in the diet of bears, and of bears as consumers and key agents supporting the transport of salmon-derived nutrients to riparian ecosystems. Salmon abundance and human disturbance are known influences on bear ecology and behaviour, though few studies have quantified shifts in bear diet due to these effects. We used stable isotope analysis to investigate how salmon escapement and human presence influenced the proportion of salmon in the diet of American black bears ( Ursus americanus Pallas, 1780) in two locations in coastal British Columbia, Canada. We found that salmon constituted a small proportion of black bear diet across sexes and ecosystems, while bears appeared to gain a similar amount of energy and lean mass from terrestrial sources. Salmon consumption was not related to the total annual abundance of salmon in a watershed but was significantly lower in large streams with regular human presence, suggesting that human disturbance can cause a dietary shift in bears that could have important consequences to their fitness. We also observed that the isotopic signatures of key bear foods did not vary between foliage and fruit, simplifying data collection for future isotopic studies on bear diet.
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Affiliation(s)
| | - Jonathan Van Elslander
- Department of Earth, Environmental and Geographic Sciences, Irving K. Barber School of Arts and Sciences, University of British Columbia Okanagan, 1177 Research Road, Kelowna, BC V1V 1V7, Canada
| | - G. Mowat
- Department of Earth, Environmental and Geographic Sciences, Irving K. Barber School of Arts and Sciences, University of British Columbia Okanagan, 1177 Research Road, Kelowna, BC V1V 1V7, Canada
- Ministry of Forests, Lands and Natural Resource Operations and Rural Development, Wildlife and Habitat Branch, Suite 401-333 Victoria Street, Nelson, BC V1L 4K3, Canada
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4
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Pathways for cross-boundary effects of biodiversity on ecosystem functioning. Trends Ecol Evol 2022; 37:454-467. [DOI: 10.1016/j.tree.2021.12.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 12/16/2021] [Accepted: 12/17/2021] [Indexed: 11/22/2022]
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5
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Davidson KH, Starzomski BM, El‐Sabaawi R, Hocking MD, Reynolds JD, Wickham SB, Darimont CT. Marine subsidy promotes spatial and dietary niche variation in an omnivore, the Keen's mouse ( Peromyscus keeni). Ecol Evol 2021; 11:17700-17722. [PMID: 35003633 PMCID: PMC8717356 DOI: 10.1002/ece3.8225] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Revised: 09/08/2021] [Accepted: 09/10/2021] [Indexed: 11/17/2022] Open
Abstract
Marine-derived resource subsidies can generate intrapopulation variation in the behaviors and diets of terrestrial consumers. How omnivores respond, given their multiple trophic interactions, is not well understood. We sampled mice (Peromyscus keeni) and their food sources at five sites on three islands of the Central Coast of British Columbia, Canada, to test predictions regarding variation in the spatial behavior and consumption of marine-subsidized foods among individuals. About 50% of detections (n = 27 recaptures) occurred at traps closest to shoreline (25 m), with capture frequencies declining significantly inland (up to 200 m). Stable isotope signatures (δ 13C and δ 15N), particularly δ 15N, in plant foods, forest arthropod prey, and mouse feces were significantly enriched near shorelines compared with inland, while δ 13C patterns were more variable. Bayesian isotope mixing models applied to isotope values in mouse hair indicated that over one-third (35-37%) of diet was comprised of beach-dwelling arthropods, a marine-derived food source. Males were more abundant near the shoreline than females and consumed more marine-derived prey, regardless of reproductive status or availability of other food sources. Our results identify how multiple pathways of marine nutrient transfer can subsidize terrestrial omnivores and how subsets of recipient populations can show variation in spatial and dietary response.
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Affiliation(s)
- Katie H. Davidson
- Department of GeographyUniversity of VictoriaVictoriaBritish ColumbiaCanada
- Hakai InstituteHeriot BayBritish ColumbiaCanada
| | - Brian M. Starzomski
- Hakai InstituteHeriot BayBritish ColumbiaCanada
- School of Environmental StudiesUniversity of VictoriaVictoriaBritish ColumbiaCanada
| | - Rana El‐Sabaawi
- Department of BiologyUniversity of VictoriaVictoriaBritish ColumbiaCanada
| | - Morgan D. Hocking
- School of Environmental StudiesUniversity of VictoriaVictoriaBritish ColumbiaCanada
- Ecofish Research Ltd.VictoriaBritish ColumbiaCanada
| | - John D. Reynolds
- Hakai InstituteHeriot BayBritish ColumbiaCanada
- Department of Biological SciencesSimon Fraser UniversityBurnabyBritish ColumbiaCanada
| | - Sara B. Wickham
- Hakai InstituteHeriot BayBritish ColumbiaCanada
- School of Environmental StudiesUniversity of VictoriaVictoriaBritish ColumbiaCanada
- Present address:
School of Environment, Resources and SustainabilityUniversity of WaterlooWaterlooOntarioCanada
| | - Chris T. Darimont
- Department of GeographyUniversity of VictoriaVictoriaBritish ColumbiaCanada
- Hakai InstituteHeriot BayBritish ColumbiaCanada
- Raincoast Conservation FoundationSidneyBritish ColumbiaCanada
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6
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Porter B, Gregovich DP, Crupi AP, Pendleton GW, Bethune SW. Black Bears Select Large Woody Structures for Dens in Southeast Alaska. J Wildl Manage 2021. [DOI: 10.1002/jwmg.22097] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Boyd Porter
- Alaska Department of Fish and Game, Division of Wildlife Conservation 2030 Sea Level Drive Ketchikan AK 99901 USA
| | - David P. Gregovich
- Alaska Department of Fish and Game, Division of Wildlife Conservation PO Box 110024 Juneau AK 99811 USA
| | - Anthony P. Crupi
- Alaska Department of Fish and Game, Division of Wildlife Conservation PO Box 110024 Juneau AK 99811 USA
| | - Grey W. Pendleton
- Alaska Department of Fish and Game, Division of Wildlife Conservation PO Box 110024 Juneau AK 99811 USA
| | - Stephen W. Bethune
- Alaska Department of Fish and Game, Division of Wildlife Conservation 304 Lake Street #103 Sitka AK 99835 USA
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Service CN, Ingram T, Reimchen TE, Darimont CT. Intrapopulation foraging niche variation between phenotypes and genotypes of Spirit bear populations. Ecol Evol 2021; 11:5025-5037. [PMID: 34025989 PMCID: PMC8131816 DOI: 10.1002/ece3.7276] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 12/23/2020] [Accepted: 01/09/2021] [Indexed: 11/07/2022] Open
Abstract
Foraging niche variation within a species can contribute to the maintenance of phenotypic diversity. The multiniche model posits that phenotypes occupying different niches can contribute to the maintenance of balanced polymorphisms. Using coastal populations of black bears (Ursus americanus kermodei) from British Columbia, Canada, we examined potential foraging niche divergence between phenotypes (black and white "Spirit" coat color) and between genotypes (black-coated homozygote and heterozygous). We applied the Bayesian multivariate models, with biotracers of diet (δ13C and δ15N) together comprising the response variable, to draw inference about foraging niche variation. Variance-covariance matrices from multivariate linear mixed-effect models were visualized as the Bayesian standard ellipses in δ13C and δ15N isotopic space to assess potential seasonal and annual niche variation between phenotypes and genotypes. We did not detect a difference in annual isotopic foraging niche area in comparisons between genotypes or phenotypes. Consistent with previous field experimental and isotopic analyses, however, we found that white phenotype Spirit bears were modestly more enriched in δ15N during the fall foraging season, though with our modest sample sizes these results were not significant. Although also not statistically significant, variation in isotopic niches between genotypes revealed that heterozygotes were moderately more enriched in δ13C along hair segments grown during fall foraging compared with black-coated homozygotes. To the extent to which the pattern of elevated δ15N and δ13C may signal the consumption of salmon (Oncorhynchus spp.), as well as the influence of salmon consumption on reproductive fitness, these results suggest that black-coated heterozygotes could have a minor selective advantage in the fall compared with black-coated homozygotes. More broadly, our multivariate approach, coupled with knowledge of genetic variation underlying a polymorphic trait, provides new insight into the potential role of a multiniche mechanism in maintaining this rare morph of conservation priority in Canada's Great Bear Rainforest and could offer new understanding into polymorphisms in other systems.
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Affiliation(s)
- Christina N. Service
- Department of GeographyUniversity of VictoriaVictoriaBCCanada
- Raincoast Conservation FoundationSidneyBCCanada
- Kitasoo Xai'xais Stewardship AuthorityKitasoo/Xai'xais First NationKlemtuBCCanada
| | - Travis Ingram
- Department of ZoologyUniversity of OtagoDunedinNew Zealand
| | | | - Chris T. Darimont
- Department of GeographyUniversity of VictoriaVictoriaBCCanada
- Raincoast Conservation FoundationSidneyBCCanada
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8
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Abrahms B, Aikens EO, Armstrong JB, Deacy WW, Kauffman MJ, Merkle JA. Emerging Perspectives on Resource Tracking and Animal Movement Ecology. Trends Ecol Evol 2021; 36:308-320. [DOI: 10.1016/j.tree.2020.10.018] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 10/14/2020] [Accepted: 10/23/2020] [Indexed: 12/26/2022]
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9
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Levi T, Hilderbrand GV, Hocking MD, Quinn TP, White KS, Adams MS, Armstrong JB, Crupi AP, Darimont CT, Deacy W, Gilbert SL, Ripple WJ, Shakeri YN, Wheat RE, Wilmers CC. Community Ecology and Conservation of Bear-Salmon Ecosystems. Front Ecol Evol 2020. [DOI: 10.3389/fevo.2020.513304] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Apex predators play keystone roles in ecosystems through top-down control, but the effects of apex omnivores on ecosystems could be more varied because changes in the resource base alter their densities and reverberate through ecosystems in complex ways. In coastal temperate ecosystems throughout much of the Northern Hemisphere, anadromous salmon once supported abundant bear populations, but both taxa have declined or been extirpated from large parts of their former ranges with limited research on the consequences of diminished or absent interactions among species. Here we review the biogeography of bear-salmon interactions and the role of salmon-subsidized bears in (1) resource provisioning to plants and scavengers through the distribution of salmon carcasses, (2) competition among bears and other large carnivores, (3) predation of ungulate neonates, (4) seed dispersal, and (5) resource subsidies to rodents with seed-filled scats. In addition to our review of the literature, we present original data to demonstrate two community-level patterns that are currently unexplained. First, deer densities appear to be consistently higher on islands with abundant brown bears than adjacent islands with black bears and wolves, and moose calf survival is higher at low bear densities (<∼25 bears per 100 km2) but is constant across the vast majority of bear densities found in the wild (i.e., ∼>25 bears per 100 km2). Our review and empirical data highlight key knowledge gaps and research opportunities to understand the complex ecosystem effects related to bear-salmon interactions.
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10
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Stable Isotopes Reveal Variation in Consumption of Pacific Salmon by Brown Bears, Despite Ready Access in Small Streams. JOURNAL OF FISH AND WILDLIFE MANAGEMENT 2020. [DOI: 10.3996/jfwm-20-034] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Abstract
Brown bears Ursus arctos consume a wide range of organisms, including ungulates and plants, but Pacific salmon Oncorhynchus spp. are especially important to their diet where their ranges overlap. Although some brown bears minimize antagonistic encounters with other brown bears or infanticide by avoiding streams where salmon spawn, studies generally assume that brown bears with ready access to salmon feed heavily on them. To test this assumption, and the hypothesis that male brown bears would feed more heavily on salmon than females (owing to their sexual size dimorphism), we collected hair samples from brown bears by using barbed wire placed on six small tributaries of Lake Aleknagik, Alaska, USA, where adult Sockeye Salmon Oncorhynchus nerka are readily accessible and frequently consumed by brown bears. Analysis of DNA distinguished among the different brown bears leaving the hair samples, some of which were sampled multiple times within and among years. We assessed the contribution of salmon to the diet of individual brown bears by using carbon and nitrogen stable isotope signatures. The 77 samples analyzed from 31 different bears over 4 y showed isotopic ratios consistent with reliance on salmon, but the wide range of isotopic signatures included values suggesting variable, and in one case considerable, use of terrestrial resources. Stable isotope signatures did not differ between male and female brown bears, nor did they differ between two sides of the lake, despite marked differences in Sockeye Salmon density. We collected the hair samples when salmon were present, so there was some uncertainty regarding whether they reflected feeding during the current or previous season. Notwithstanding this caveat, the results are consistent with the hypothesis that salmon were sufficiently available to provide food for the brown bears and that the considerable isotopic variation among brown bears with access to salmon reflected their age, status, and behavior.
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11
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Ferretti F, Lovari S, Lucherini M, Hayward M, Stephens PA. Only the largest terrestrial carnivores increase their dietary breadth with increasing prey richness. Mamm Rev 2020. [DOI: 10.1111/mam.12197] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Francesco Ferretti
- Research Unit of Behavioural Ecology, Ethology and Wildlife Management Department of Life Sciences University of Siena Via P.A. Mattioli 4 53100 Siena Italy
| | - Sandro Lovari
- Research Unit of Behavioural Ecology, Ethology and Wildlife Management Department of Life Sciences University of Siena Via P.A. Mattioli 4 53100 Siena Italy
- Maremma Natural History Museum Strada Corsini 5 58100 Grosseto Italy
| | - Mauro Lucherini
- Grupo de Ecología Comportamental de Mamíferos Laboratorio de Fisiología Animal INBIOSUR (Instituto de Investigaciones Biológicas y Biomédicas del Sur) Universidad Nacional del Sur ‐ CONICET San Juan 671 8000 Bahía Blanca Argentina
| | - Matt Hayward
- Conservation Biology Research Group School of Environmental and Life Sciences University of Newcastle Callaghan NSW 2308 Australia
- Centre for Invasion Biology University of Pretoria X0001 Pretoria South Africa
| | - Philip A. Stephens
- Conservation Ecology Group Department of Biosciences Durham University South Road Durham DH1 3LE UK
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12
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Tanaka R, Hirashima K, Kunishima T, Uno H, Sato T. Phenological diversity of freshwater migration can prolong assemblage‐level migration period in amphidromous fishes in a temperate river system in Japan. Ecol Res 2020. [DOI: 10.1111/1440-1703.12132] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ryosuke Tanaka
- Department of Biology, Graduate School of Sciences Kobe University Japan
| | | | | | - Hiromi Uno
- Center for Ecological Research Kyoto University Japan
| | - Takuya Sato
- Department of Biology, Graduate School of Sciences Kobe University Japan
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13
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Lincoln AE, Hilborn R, Wirsing AJ, Quinn TP. Managing salmon for wildlife: Do fisheries limit salmon consumption by bears in small Alaskan streams? ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2020; 30:e02061. [PMID: 31863535 DOI: 10.1002/eap.2061] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2019] [Revised: 10/28/2019] [Accepted: 11/13/2019] [Indexed: 06/10/2023]
Abstract
Ecosystem-based management requires consideration of overlapping resource use between humans and other consumers. Pacific salmon are an important resource for both fisheries and populations of wildlife around the Pacific rim, including coastal brown bears (Ursus arctos); salmon consumption has been positively linked to bear density, body size, and reproductive rate. As a case study within the broader context of human-wildlife competition for food, we used 16-22 yr of empirical data in four different salmon-bearing systems in southwestern Alaska to explore the relationship between sockeye salmon (Oncorhynchus nerka) availability and consumption by bears. We found a negative relationship between the annual biomass of salmon available to bears and the fraction of biomass consumed per fish, and a saturating relationship between salmon availability and the total annual biomass of salmon consumed by bears. Under modeled scenarios, bear consumption of salmon was predicted to increase only with dramatic (on the order of 50-100%) increases in prey availability. Even such large increases in salmon abundance were estimated to produce relatively modest increases in per capita salmon consumption by bears (2.4-4.8 kg·bear-1 ·d-1 , 15-59% of the estimated daily maximum per capita intake), in part because bears did not consume salmon entirely, especially when salmon were most available. Thus, while bears catching salmon in small streams may be limited by salmon harvest in some years, current management of the systems we studied is sufficient for bear populations to reach maximum salmon consumption every 2-4 yr. Consequently, allocating more salmon for brown bear conservation would unlikely result in an ecologically significant response for bears in these systems, though other ecosystem components might benefit. Our results highlight the need for documenting empirical relationships between prey abundance and consumption, particularly in systems with partial consumption, when evaluating the ecological response of managing prey resources for wildlife populations.
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Affiliation(s)
- Alexandra E Lincoln
- School of Aquatic and Fishery Sciences, University of Washington, 1122 Northeast Boat Street, Seattle, Washington, 98195, USA
| | - Ray Hilborn
- School of Aquatic and Fishery Sciences, University of Washington, 1122 Northeast Boat Street, Seattle, Washington, 98195, USA
| | - Aaron J Wirsing
- School of Environmental and Forest Sciences, University of Washington, 4000 15th Avenue Northeast, Seattle, Washington, 98195, USA
| | - Thomas P Quinn
- School of Aquatic and Fishery Sciences, University of Washington, 1122 Northeast Boat Street, Seattle, Washington, 98195, USA
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14
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Armstrong JB, Schindler DE, Cunningham CJ, Deacy W, Walsh P. Watershed complexity increases the capacity for salmon–wildlife interactions in coastal ecosystems. Conserv Lett 2019. [DOI: 10.1111/conl.12689] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Affiliation(s)
| | - Daniel E. Schindler
- School of Aquatic and Fishery Sciences University of Washington Seattle Washington
| | - Curry J. Cunningham
- College of Fisheries and Ocean Sciences University of Alaska Fairbanks Juneau Alaska
| | - William Deacy
- Department of Fisheries and Wildlife Oregon State University Corvallis Oregon
- Arctic Network U.S. National Park Service 4175 Geist Road Fairbanks Alaska 99709 USA
| | - Patrick Walsh
- U.S. Fish and Wildlife Service Togiak National Wildlife Refuge Togiak Alaska
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15
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He F, Zarfl C, Bremerich V, David JNW, Hogan Z, Kalinkat G, Tockner K, Jähnig SC. The global decline of freshwater megafauna. GLOBAL CHANGE BIOLOGY 2019; 25:3883-3892. [PMID: 31393076 DOI: 10.1111/gcb.14753] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 06/05/2019] [Indexed: 05/12/2023]
Abstract
Freshwater ecosystems are among the most diverse and dynamic ecosystems on Earth. At the same time, they are among the most threatened ecosystems but remain underrepresented in biodiversity research and conservation efforts. The rate of decline of vertebrate populations is much higher in freshwaters than in terrestrial or marine realms. Freshwater megafauna (i.e., freshwater animals that can reach a body mass ≥30 kg) are intrinsically prone to extinction due to their large body size, complex habitat requirements and slow life-history strategies such as long life span and late maturity. However, population trends and distribution changes of freshwater megafauna, at continental or global scales, remain unclear. In the present study, we compiled population data of 126 freshwater megafauna species globally from the Living Planet Database and available literature, and distribution data of 44 species inhabiting Europe and the United States from literature and databases of the International Union for Conservation of Nature and NatureServe. We quantified changes in population abundance and distribution range of freshwater megafauna species. Globally, freshwater megafauna populations declined by 88% from 1970 to 2012, with the highest declines in the Indomalaya and Palearctic realms (-99% and -97%, respectively). Among taxonomic groups, mega-fishes exhibited the greatest global decline (-94%). In addition, freshwater megafauna experienced major range contractions. For example, distribution ranges of 42% of all freshwater megafauna species in Europe contracted by more than 40% of historical areas. We highlight the various sources of uncertainty in tracking changes in populations and distributions of freshwater megafauna, such as the lack of monitoring data and taxonomic and spatial biases. The detected trends emphasize the critical plight of freshwater megafauna globally and highlight the broader need for concerted, targeted and timely conservation of freshwater biodiversity.
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Affiliation(s)
- Fengzhi He
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Berlin, Germany
- Institute of Biology, Freie Universität Berlin, Berlin, Germany
- School of Geography, Queen Mary University of London, London, UK
| | - Christiane Zarfl
- Center for Applied Geosciences, Eberhard Karls Universität Tübingen, Tübingen, Germany
| | - Vanessa Bremerich
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Berlin, Germany
| | - Jonathan N W David
- School of Geography and the Environment, University of Oxford, Oxford, UK
| | - Zeb Hogan
- Department of Biology, University of Nevada, Reno, NV, USA
| | - Gregor Kalinkat
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Berlin, Germany
| | - Klement Tockner
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Berlin, Germany
- Institute of Biology, Freie Universität Berlin, Berlin, Germany
- Austrian Science Fund (FWF), Vienna, Austria
| | - Sonja C Jähnig
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Berlin, Germany
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16
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Harding JMS, Harding JN, Field RD, Pendray JE, Swain NR, Wagner MA, Reynolds JD. Landscape Structure and Species Interactions Drive the Distribution of Salmon Carcasses in Coastal Watersheds. Front Ecol Evol 2019. [DOI: 10.3389/fevo.2019.00192] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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17
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Service CN, Bateman AW, Adams MS, Artelle KA, Reimchen TE, Paquet PC, Darimont CT. Salmonid species diversity predicts salmon consumption by terrestrial wildlife. J Anim Ecol 2019; 88:392-404. [PMID: 30618046 PMCID: PMC6850012 DOI: 10.1111/1365-2656.12932] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 11/07/2018] [Indexed: 11/30/2022]
Abstract
Resource waves—spatial variation in resource phenology that extends feeding opportunities for mobile consumers—can affect the behaviour and productivity of recipient populations. Interspecific diversity among Pacific salmon species (Oncorhynchus spp.) creates staggered spawning events across space and time, thereby prolonging availability to terrestrial wildlife. We sought to understand how such variation might influence consumption by terrestrial predators compared with resource abundance and intra‐ and interspecific competition. Using stable isotope analysis, we investigated how the proportion of salmon in the annual diet of male black bears (Ursus americanus; n = 405) varies with species diversity and density of spawning salmon biomass, while also accounting for competition with sympatric black and grizzly bears (U. arctos horribilis), in coastal British Columbia, Canada. We found that the proportion of salmon in the annual diet of black bears was ≈40% higher in the absence of grizzly bears, but detected little effect of relative black bear density and salmon biomass density. Rather, salmon diversity had the largest positive effect on consumption. On average, increasing diversity from one salmon species to ~four (with equal biomass contributions) approximately triples the proportion of salmon in diet. Given the importance of salmon to bear life histories, this work provides early empirical support for how resource waves may increase the productivity of consumers at population and landscape scales. Accordingly, terrestrial wildlife management might consider maintaining not only salmon abundance but also diversity.
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Affiliation(s)
- Christina N Service
- Department of Geography, University of Victoria, Victoria, British Columbia, Canada.,Hakai Institute, Heriot Bay, British Columbia, Canada.,Raincoast Conservation Foundation, Sidney, British Columbia, Canada.,Spirit Bear Research Foundation, Klemtu, British Columbia, Canada
| | - Andrew W Bateman
- Department of Geography, University of Victoria, Victoria, British Columbia, Canada.,Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada.,Salmon Coast Field Station, Echo Bay, British Columbia, Canada
| | - Megan S Adams
- Department of Geography, University of Victoria, Victoria, British Columbia, Canada.,Hakai Institute, Heriot Bay, British Columbia, Canada.,Raincoast Conservation Foundation, Sidney, British Columbia, Canada
| | - Kyle A Artelle
- Department of Geography, University of Victoria, Victoria, British Columbia, Canada.,Hakai Institute, Heriot Bay, British Columbia, Canada.,Raincoast Conservation Foundation, Sidney, British Columbia, Canada.,Earth to Ocean Research Group, Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Thomas E Reimchen
- Department of Biology, University of Victoria, Victoria, British Columbia, Canada
| | - Paul C Paquet
- Department of Geography, University of Victoria, Victoria, British Columbia, Canada.,Raincoast Conservation Foundation, Sidney, British Columbia, Canada
| | - Chris T Darimont
- Department of Geography, University of Victoria, Victoria, British Columbia, Canada.,Hakai Institute, Heriot Bay, British Columbia, Canada.,Raincoast Conservation Foundation, Sidney, British Columbia, Canada
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