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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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Benedict BM, Thompson DP, Crouse JA, Hamer GL, Barboza PS. Trapped between food, heat, and insects: Movement of moose ( Alces alces) and exposure to flies in the boreal forest of Alaska. Ecol Evol 2024; 14:e11625. [PMID: 38911494 PMCID: PMC11192998 DOI: 10.1002/ece3.11625] [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: 11/15/2023] [Revised: 05/30/2024] [Accepted: 06/10/2024] [Indexed: 06/25/2024] Open
Abstract
Moose (Alces alces) in the boreal forest habitats of Alaska are unlike other northern ungulates because they tolerate high densities of flies (Diptera) even though flies cause wounds and infections during the warm summer months. Moose move to find food and to find relief from overheating (hyperthermia) but do they avoid flies? We used GPS collars to measure the rate of movement (m⋅h-1) and the time spent (min⋅day-1) by enclosed moose in four habitats: wetlands, black spruce, early seral boreal forest, and late seral boreal forest. Fly traps were used in each habitat to quantify spatio-temporal abundance. Average daily air temperatures increased into July when peak biomass of forage for moose was greatest in early seral boreal forest habitats (424.46 vs. 25.15 kg⋅ha-1 on average in the other habitats). Average daily air temperatures were 1.7°C cooler in black spruce than other habitats, but fly abundance was greatest in black spruce (approximately 4-fold greater on average than the other habitats). Moose increased their movement rate with counts of biting flies (mosquitoes, black flies, horse and deer flies), but not non-biting flies (coprophagous flies). However, as air temperature increased (above 14.7°C) moose spent more time in fly-abundant black spruce, than early seral boreal forest, showing great tolerance for mosquitoes. Warm summer temperatures appear to cause moose to trade-off foraging in fly-sparse habitats for resting and dissipating heat in shady, wet habitats with abundant flies that adversely affect the fitness of moose.
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Affiliation(s)
- Bridgett M. Benedict
- Department of Ecology and Conservation BiologyTexas A&M UniversityCollege StationTexasUSA
| | - Daniel P. Thompson
- Alaska Department of Fish and GameKenai Moose Research CenterSoldotnaAlaskaUSA
| | - John A. Crouse
- Alaska Department of Fish and GameKenai Moose Research CenterSoldotnaAlaskaUSA
| | - Gabriel L. Hamer
- Department of EntomologyTexas A&M UniversityCollege StationTexasUSA
| | - Perry S. Barboza
- Department of Ecology and Conservation BiologyTexas A&M UniversityCollege StationTexasUSA
- Department of Rangelands Wildlife and Fisheries ManagementTexas A&M UniversityCollege StationTexasUSA
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Denryter K, Stephenson TR, Monteith KL. Migratory behaviours are risk-sensitive to physiological state in an elevational migrant. CONSERVATION PHYSIOLOGY 2024; 12:coae029. [PMID: 38779433 PMCID: PMC11109817 DOI: 10.1093/conphys/coae029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Revised: 04/17/2024] [Accepted: 04/23/2024] [Indexed: 05/25/2024]
Abstract
Accretion of body fat by animals is an important physiological adaptation that may underpin seasonal behaviours, especially where it modulates risk associated with a particular behaviour. Using movement data from male Sierra Nevada bighorn sheep (Ovis canadensis sierrae), we tested the hypothesis that migratory behaviours were risk-sensitive to physiological state (indexed by body fat). Sierra bighorn face severe winter conditions at high elevations and higher predation risk at lower elevations. Given that large body fat stores ameliorate starvation risk, we predicted that having small body fat stores would force animals to migrate to lower elevations with more abundant food supplies. We also predicted that body fat stores would influence how far animals migrate, with the skinniest animals migrating the furthest down in elevation (to access the most abundant food supplies at that time of year). Lastly, we predicted that population-level rates of switching between migratory tactics would be inversely related to body fat levels because as body fat levels decrease, animals exhibiting migratory plasticity should modulate their risk of starvation by switching migratory tactics. Consistent with our predictions, probability of migration and elevational distance migrated increased with decreasing body fat, but effects differed amongst metapopulations. Population-level switching rates also were inversely related to population-level measures of body fat prior to migration. Collectively, our findings suggest migration was risk-sensitive to physiological state, and failure to accrete adequate fat may force animals to make trade-offs between starvation and predation risk. In complex seasonal environments, risk-sensitive migration yields a layer of flexibility that should aid long-term persistence of animals that can best modulate their risk by attuning behaviour to physiological state.
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Affiliation(s)
- Kristin Denryter
- Haub School of Environment and Natural Resources, University of Wyoming, Bim Kendall House 804 E Fremont St, Laramie, WY 82072, USA
| | - Thomas R. Stephenson
- California Department of Fish and Wildlife, Sierra Nevada Bighorn Sheep Recovery Program, 787 N Main St., Bishop, CA 93514, USA
| | - Kevin L. Monteith
- Haub School of Environment and Natural Resources, Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and Physiology, University of Wyoming, Bim Kendall House 804 E Fremont St, Laramie, WY 82072, USA
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Barboza PS, Shively RD, Thompson DP. Robust Responses of Female Caribou to Changes in Food Supply. ECOLOGICAL AND EVOLUTIONARY PHYSIOLOGY 2024; 97:29-52. [PMID: 38717369 DOI: 10.1086/729668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2024]
Abstract
AbstractUngulates can respond to changes in food supply by altering foraging behavior, digestive function, and metabolism. A multifaceted response to an environmental change is considered robust. Short seasons of plant growth make herbivores sensitive to changes in food supply because maintenance and production must be accomplished in less time with fewer options in a more fragile response. Caribou live at high latitudes where short summers constrain their response to changes in food supply. We measured the ability of female caribou to resist and tolerate changes in the quality and quantity of their food supply during winter and summer. Caribou resisted changes in food abundance and quality by changing food intake and physical activity with changes in daily temperature within each season. Peak food intake rose by 134% from winter pregnancy to summer lactation (98 vs. 229 g kg-0.75 d-1), as digestible requirements to maintain the body increased by 85% for energy (1,164 vs. 2,155 kJ kg-0.75 d-1) and by 266% for N (0.79 vs. 2.89 g N kg-0.75 d-1). Caribou required a diet with a digestible content of 12 kJ g-1 and 0.8% N in pregnancy, 18 kJ g-1 and 1.9% N in early lactation, and 11 kJ g-1 and 1.2% N in late lactation, which corresponds with the phenology of the wild diet. Female caribou tolerated restriction of ad lib. food intake to 58% of their energy requirement (680 vs. 1,164 kJ kg-0.75 d-1) during winter pregnancy and to 84% of their energy requirement (1,814 vs. 2,155 kJ kg-0.75 d-1) during summer lactation without a change in stress level, as indicated by fecal corticosterone concentration. Conversely, caribou can respond to increased availability of food with a spare capacity to process digestible energy and N at 123% (2,642 vs. 2,155 kJ kg-0.75 d-1) and 145% (4.20 vs. 2.89 g N kg-0.75 d-1) of those respective requirements during lactation. Robust responses to changes in food supply allow caribou to sustain reproduction, which would buffer demographic response. However, herds may decline when thresholds of behavioral resistance and physiological tolerance are frequently exceeded. Therefore, the challenge for managing declining populations of caribou and other robust species is to identify declines in robustness before their response becomes fragile.
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Johnson HE, Lenart EA, Gustine DD, Adams LG, Barboza PS. Survival and reproduction in Arctic caribou are associated with summer forage and insect harassment. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.899585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Investigators have speculated that the climate-driven “greening of the Arctic” may benefit barren-ground caribou populations, but paradoxically many populations have declined in recent years. This pattern has raised concerns about the influence of summer habitat conditions on caribou demographic rates, and how populations may be impacted in the future. The short Arctic summer provides caribou with important forage resources but is also the time they are exposed to intense harassment by insects, factors which are both being altered by longer, warmer growing seasons. To better understand the effects of summer forage and insect activity on Arctic caribou demographic rates, we investigated the influence of estimated forage biomass, digestible energy (DE), digestible nitrogen (DN), and mosquito activity on the reproductive success and survival of adult females in the Central Arctic Herd on the North Slope of Alaska. We tested the hypotheses that greater early summer DN would increase subsequent reproduction (parturition and late June calving success) while greater biomass and DE would increase adult survival (September–May), and that elevated mosquito activity would reduce both demographic rates. Because the period when abundant forage DN is limited and overlaps with the period of mosquito harassment, we also expected years with low DN and high harassment to synergistically reduce caribou reproductive success. Examining these relationships at the individual-level, using GPS-collared females, and at the population-level, using long-term monitoring data, we generally found support for our expectations. Greater early summer DN was associated with increased subsequent calving success, while greater summer biomass was associated with increased adult survival. Mosquito activity was associated with reductions in adult female parturition, late June calving success, and survival, and in years with low DN, had compounding effects on subsequent late June calving success. Our findings indicate that summer nutrition and mosquito activity collectively influence the demographic rates of Arctic caribou, and may impact the dynamics of populations in the future under changing environmental conditions.
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Smiley RA, Wagler BL, LaSharr TN, Denryter KA, Stephenson TR, Courtemanch AB, Mong TW, Lutz D, McWhirter D, Brimeyer D, Hnilicka P, Lowrey B, Monteith KL. Heterogeneity in risk‐sensitive allocation of somatic reserves in a long‐lived mammal. Ecosphere 2022. [DOI: 10.1002/ecs2.4161] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Rachel A. Smiley
- Haub School of Environment and Natural Resources, Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and Physiology University of Wyoming Laramie Wyoming USA
| | - Brittany L. Wagler
- Haub School of Environment and Natural Resources, Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and Physiology University of Wyoming Laramie Wyoming USA
| | - Tayler N. LaSharr
- Haub School of Environment and Natural Resources, Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and Physiology University of Wyoming Laramie Wyoming USA
| | | | - Thomas R. Stephenson
- Sierra Nevada Bighorn Sheep Recovery Program, California Department of Fish and Wildlife Bishop California USA
| | | | - Tony W. Mong
- Wyoming Game and Fish Department Cody Wyoming USA
| | - Daryl Lutz
- Wyoming Game and Fish Department Lander Wyoming USA
| | | | - Doug Brimeyer
- Wyoming Game and Fish Department Cheyenne Wyoming USA
| | | | - Blake Lowrey
- Fish and Wildlife Ecology and Management Program, Department of Ecology Montana State University Bozeman Montana USA
| | - Kevin L. Monteith
- Haub School of Environment and Natural Resources, Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and Physiology University of Wyoming Laramie Wyoming USA
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