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Lamb CT, Williams S, Boutin S, Bridger M, Cichowski D, Cornhill K, DeMars C, Dickie M, Ernst B, Ford A, Gillingham MP, Greene L, Heard DC, Hebblewhite M, Hervieux D, Klaczek M, McLellan BN, McNay RS, Neufeld L, Nobert B, Nowak JJ, Pelletier A, Reid A, Roberts AM, Russell M, Seip D, Seip C, Shores C, Steenweg R, White S, Wittmer HU, Wong M, Zimmerman KL, Serrouya R. Effectiveness of population-based recovery actions for threatened southern mountain caribou. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2024; 34:e2965. [PMID: 38629596 DOI: 10.1002/eap.2965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 10/12/2023] [Accepted: 12/20/2023] [Indexed: 06/04/2024]
Abstract
Habitat loss is affecting many species, including the southern mountain caribou (Rangifer tarandus caribou) population in western North America. Over the last half century, this threatened caribou population's range and abundance have dramatically contracted. An integrated population model was used to analyze 51 years (1973-2023) of demographic data from 40 southern mountain caribou subpopulations to assess the effectiveness of population-based recovery actions at increasing population growth. Reducing potential limiting factors on threatened caribou populations offered a rare opportunity to identify the causes of decline and assess methods of recovery. Southern mountain caribou abundance declined by 51% between 1991 and 2023, and 37% of subpopulations were functionally extirpated. Wolf reduction was the only recovery action that consistently increased population growth when applied in isolation, and combinations of wolf reductions with maternal penning or supplemental feeding provided rapid growth but were applied to only four subpopulations. As of 2023, recovery actions have increased the abundance of southern mountain caribou by 52%, compared to a simulation with no interventions. When predation pressure was reduced, rapid population growth was observed, even under contemporary climate change and high levels of habitat loss. Unless predation is reduced, caribou subpopulations will continue to be extirpated well before habitat conservation and restoration can become effective.
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Affiliation(s)
- Clayton T Lamb
- Wildlife Science Center, Biodiversity Pathways, Kelowna, British Columbia, Canada
- Department of Biology, University of British Columbia, Kelowna, British Columbia, Canada
| | - Sara Williams
- Wildlife Biology Program, University of Montana, Missoula, Montana, USA
| | - Stan Boutin
- Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Michael Bridger
- Ministry of Water, Land and Resource Stewardship, Government of British Columbia, Victoria, British Columbia, Canada
| | | | - Kristina Cornhill
- Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Craig DeMars
- Wildlife Science Center, Biodiversity Pathways, Kelowna, British Columbia, Canada
| | - Melanie Dickie
- Wildlife Science Center, Biodiversity Pathways, Kelowna, British Columbia, Canada
- Department of Biology, University of British Columbia, Kelowna, British Columbia, Canada
| | - Bevan Ernst
- Ministry of Water, Land and Resource Stewardship, Government of British Columbia, Victoria, British Columbia, Canada
| | - Adam Ford
- Wildlife Science Center, Biodiversity Pathways, Kelowna, British Columbia, Canada
- Department of Biology, University of British Columbia, Kelowna, British Columbia, Canada
| | - Michael P Gillingham
- Ecosystem Science and Management, University of Northern British Columbia, Prince George, British Columbia, Canada
| | - Laura Greene
- Ministry of Water, Land and Resource Stewardship, Government of British Columbia, Victoria, British Columbia, Canada
| | - Douglas C Heard
- Tithonus Wildlife Research, Prince George, British Columbia, Canada
| | - Mark Hebblewhite
- Wildlife Biology Program, University of Montana, Missoula, Montana, USA
| | - Dave Hervieux
- Alberta Environment and Protected Areas, Government of Alberta, Grande Prairie, Alberta, Canada
| | - Mike Klaczek
- Ministry of Forests, Government of British Columbia, Victoria, British Columbia, Canada
| | - Bruce N McLellan
- International Union for the Conservation of Nature Bear Specialist Group, D'Arcy, British Columbia, Canada
| | - R Scott McNay
- Wildlife Infometrics Inc., Mackenzie, British Columbia, Canada
| | | | - Barry Nobert
- Alberta Environment and Protected Areas, Government of Alberta, Grande Prairie, Alberta, Canada
| | | | - Agnès Pelletier
- Ministry of Water, Land and Resource Stewardship, Government of British Columbia, Victoria, British Columbia, Canada
| | - Aaron Reid
- Ministry of Water, Land and Resource Stewardship, Government of British Columbia, Victoria, British Columbia, Canada
| | - Anne-Marie Roberts
- Ministry of Water, Land and Resource Stewardship, Government of British Columbia, Victoria, British Columbia, Canada
| | - Mike Russell
- Alberta Environment and Protected Areas, Government of Alberta, Grande Prairie, Alberta, Canada
| | - Dale Seip
- Ministry of Environment, Government of British Columbia, Fort St. John, British Columbia, Canada
| | - Caroline Seip
- Alberta Environment and Protected Areas, Government of Alberta, Grande Prairie, Alberta, Canada
| | - Carolyn Shores
- Ministry of Water, Land and Resource Stewardship, Government of British Columbia, Victoria, British Columbia, Canada
| | - Robin Steenweg
- Canadian Wildlife Service, Environment and Climate Change Canada, Kelowna, British Columbia, Canada
| | - Shane White
- Ministry of Forests, Government of British Columbia, Victoria, British Columbia, Canada
| | - Heiko U Wittmer
- School of Biological Sciences, Victoria University of Wellington, Wellington, New Zealand
| | - Mark Wong
- Ministry of Water, Land and Resource Stewardship, Government of British Columbia, Victoria, British Columbia, Canada
| | - Kathryn L Zimmerman
- Ministry of Water, Land and Resource Stewardship, Government of British Columbia, Victoria, British Columbia, Canada
| | - Robert Serrouya
- Wildlife Science Center, Biodiversity Pathways, Kelowna, British Columbia, Canada
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Guo Q, Lu X, Xie C, Zhang J, Xu X, Qian Y, Luo X, Duan Y. Trophic Niche Differentiation in Two Sympatric Nuthatch Species ( Sitta yunnanensis and Sitta nagaensis). Animals (Basel) 2024; 14:1146. [PMID: 38672294 PMCID: PMC11047393 DOI: 10.3390/ani14081146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Revised: 03/30/2024] [Accepted: 04/02/2024] [Indexed: 04/28/2024] Open
Abstract
Sympatric closely related species may experience interspecific trophic competition due to ecological similarity; they may isolate in terms of diet or habitat use as a strategy to avoid competition. The body tissues of consumers contain stable isotope signatures information that can be applied to infer their dietary information. In this study, δ13C and δ15N stable isotopes were analyzed to determine the dietary information and trophic niches of sympatric coexisting Sitta yunnanensis and Sitta nagaensis. The results showed that the food sources of S. yunnanensis and S. nagaensis were from six orders, including Orthoptera, and the cumulative contribution rate was 99.97%, with the two species eating similar diets but at different rates. The larger δ13C of S. yunnanensis indicates that it had a wider range of habitats for feeding, while the difference in δ15N values was not significant (p > 0.05), indicating that both species feed on similar nutrient levels. As determined by Bayesian ellipses, the isotopic niches of S. yunnanensis and S. nagaensis were differentiated; the isotopic niche width of S. yunnanensis is 2.69‱2, which was larger than that of S. nagaensis (0.73‱2), indicates that differentiation between the two species in diet or habitat use reduced competition. Trophic niche differentiation and differences in foraging proportions may be the principal resource allocation mechanisms behind S. yunnanensis and S. nagaensis coexistence.
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Affiliation(s)
- Qiang Guo
- Key Laboratory for Forest Resources Conservation and Utilization in the Southwest Mountains of China, Ministry of Education, Southwest Forestry University, Kunming 650224, China; (Q.G.); (X.L.); (J.Z.)
- College of Forestry, Southwest Forestry University, Kunming 650224, China; (C.X.); (Y.Q.)
| | - Xi Lu
- Key Laboratory for Forest Resources Conservation and Utilization in the Southwest Mountains of China, Ministry of Education, Southwest Forestry University, Kunming 650224, China; (Q.G.); (X.L.); (J.Z.)
- Key Laboratory for Conserving Wildlife with Small Populations in Yunnan, Southwest Forestry University, Kunming 650224, China
| | - Chongxin Xie
- College of Forestry, Southwest Forestry University, Kunming 650224, China; (C.X.); (Y.Q.)
| | - Jiansong Zhang
- Key Laboratory for Forest Resources Conservation and Utilization in the Southwest Mountains of China, Ministry of Education, Southwest Forestry University, Kunming 650224, China; (Q.G.); (X.L.); (J.Z.)
- Key Laboratory for Conserving Wildlife with Small Populations in Yunnan, Southwest Forestry University, Kunming 650224, China
| | - Xianyin Xu
- Administration of Zixi Mountain Provincial Nature Reserve, Chuxiong 675008, China
| | - Yuhan Qian
- College of Forestry, Southwest Forestry University, Kunming 650224, China; (C.X.); (Y.Q.)
| | - Xu Luo
- Key Laboratory for Forest Resources Conservation and Utilization in the Southwest Mountains of China, Ministry of Education, Southwest Forestry University, Kunming 650224, China; (Q.G.); (X.L.); (J.Z.)
| | - Yubao Duan
- Key Laboratory for Forest Resources Conservation and Utilization in the Southwest Mountains of China, Ministry of Education, Southwest Forestry University, Kunming 650224, China; (Q.G.); (X.L.); (J.Z.)
- College of Forestry, Southwest Forestry University, Kunming 650224, China; (C.X.); (Y.Q.)
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Rioux È, Cabrol J, Lesage V. Long-term evolution of the structure of the St. Lawrence (Canada) marine ecosystem in the context of climate change and anthropogenic activities: An isotopic perceptive. Ecol Evol 2023; 13:e10740. [PMID: 38034343 PMCID: PMC10684986 DOI: 10.1002/ece3.10740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 10/31/2023] [Accepted: 11/03/2023] [Indexed: 12/02/2023] Open
Abstract
Documenting long-term changes in the trophic structure of food webs and how species respond to these changes is essential to forecast their vulnerability and resilience to environmental stressors. Over the past decades, the St. Lawrence marine ecosystem (Canada) has experienced major changes in its physical, chemical, and biological conditions from overfishing, acoustic and chemical pollution, climate change, and the increased abundance of some top predators. These changes have likely affected the trophodynamics of the ecosystem, and are suspected to have deleterious effects on endangered species of mammals and other components of the ecosystem, such as blue whales (Balaenoptera musculus), fin whales (B. physalus), and beluga (Delphinapterus leucas). This study examined the trophic structure of the St. Lawrence marine ecosystem, including the isotopic niche of various species, over two periods of contrasting pressures from anthropogenic and climatic stressors (1995-2003 vs. 2019-2021). Stable isotope ratios were measured in 1240 samples of 21 species of marine invertebrates, fishes, and mammals sampled during both periods. A significant change in the isotopic value and niche position between periods is observed in most of the sampled species. While the direction of change and effect size were not uniform among species, these changes confirmed that substantial modifications in community structure have occurred over time. Niche overlap decreased considerably among some of the pelagic and demersal fishes, and among whale species during the most recent period. Combined with a concomitant reduction in niche breadth in several species, these observations suggested that resource sharing was limited among these species. This study highlighted some degree of dietary plasticity in several species, and a long-term change in the trophic structure of the St. Lawrence marine ecosystem, with likely effects on diet composition and energetics of several populations, including endangered species.
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Affiliation(s)
- Ève Rioux
- Fisheries and Oceans CanadaMaurice Lamontagne InstituteMont‐JoliQuébecCanada
| | - Jory Cabrol
- Fisheries and Oceans CanadaMaurice Lamontagne InstituteMont‐JoliQuébecCanada
| | - Véronique Lesage
- Fisheries and Oceans CanadaMaurice Lamontagne InstituteMont‐JoliQuébecCanada
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Ayebare S, Doser JW, Plumptre AJ, Owiunji I, Mugabe H, Zipkin EF. An environmental habitat gradient and within-habitat segregation enable co-existence of ecologically similar bird species. Proc Biol Sci 2023; 290:20230467. [PMID: 37583324 PMCID: PMC10427832 DOI: 10.1098/rspb.2023.0467] [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: 02/24/2023] [Accepted: 07/21/2023] [Indexed: 08/17/2023] Open
Abstract
Niche theory predicts that ecologically similar species can coexist through multidimensional niche partitioning. However, owing to the challenges of accounting for both abiotic and biotic processes in ecological niche modelling, the underlying mechanisms that facilitate coexistence of competing species are poorly understood. In this study, we evaluated potential mechanisms underlying the coexistence of ecologically similar bird species in a biodiversity-rich transboundary montane forest in east-central Africa by computing niche overlap indices along an environmental elevation gradient, diet, forest strata, activity patterns and within-habitat segregation across horizontal space. We found strong support for abiotic environmental habitat niche partitioning, with 55% of species pairs having separate elevation niches. For the remaining species pairs that exhibited similar elevation niches, we found that within-habitat segregation across horizontal space and to a lesser extent vertical forest strata provided the most likely mechanisms of species coexistence. Coexistence of ecologically similar species within a highly diverse montane forest was determined primarily by abiotic factors (e.g. environmental elevation gradient) that characterize the Grinnellian niche and secondarily by biotic factors (e.g. vertical and horizontal segregation within habitats) that describe the Eltonian niche. Thus, partitioning across multiple levels of spatial organization is a key mechanism of coexistence in diverse communities.
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Affiliation(s)
- Samuel Ayebare
- Department of Integrative Biology, Michigan State University, East Lansing, MI 48824, USA
- Ecology, Evolution, and Behavior Program, Michigan State University, East Lansing, MI 48824, USA
- Wildlife Conservation Society (WCS), Uganda Programme, PO Box 7487, Kampala, Uganda
| | - Jeffrey W. Doser
- Department of Integrative Biology, Michigan State University, East Lansing, MI 48824, USA
- Ecology, Evolution, and Behavior Program, Michigan State University, East Lansing, MI 48824, USA
| | - Andrew J. Plumptre
- KBA Secretariat, c/o BirdLife International, David Attenborough Building, Pembroke Street, Cambridge CB2 3QZ, UK
- Conservation Science Group, Zoology Department, Cambridge University, Pembroke Street, Cambridge CB2 3QZ, UK
| | | | - Hamlet Mugabe
- Wildlife Conservation Society (WCS), Uganda Programme, PO Box 7487, Kampala, Uganda
| | - Elise F. Zipkin
- Department of Integrative Biology, Michigan State University, East Lansing, MI 48824, USA
- Ecology, Evolution, and Behavior Program, Michigan State University, East Lansing, MI 48824, USA
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