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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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Vuillaume B, Richard JH, Hamel S, Taillon J, Festa-Bianchet M, Côté SD. Birth date determines early calf survival in migratory caribou. Oecologia 2023; 202:819-830. [PMID: 37640888 DOI: 10.1007/s00442-023-05441-7] [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: 11/03/2022] [Accepted: 08/13/2023] [Indexed: 08/31/2023]
Abstract
The decline of most caribou (Rangifer tarandus) populations underlines the need to understand the determinants of key demographic parameters. In migratory caribou, we have limited information on rates and drivers of pre-weaning mortality. We fitted 60 pregnant females of the Rivière-aux-Feuilles caribou herd with GPS camera collars to track the survival of calves from birth to weaning in 2016-2018. Over the three years, calf survival rate before weaning, i.e. to 01-Sep, approximately three months of age, was 0.63 (CI 0.50-0.77). Summer mortality risk was mainly influenced by calf birth date, with calves born earlier in the calving season having a lower mortality risk than those born later. Mortality also increased when calves experienced low or high temperature during calving. This study provides the first estimates of pre-weaning survival of migratory caribou calves in this herd, illustrating the value of new technologies to collect data otherwise difficult to obtain in widely distributed migratory populations. This approach can easily be extended to other large herbivores and predators. Our study brings new insights on how climate change may affect summer juvenile survival given the increased temperatures and faster changes in plant phenology expected in the future.
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Affiliation(s)
- Barbara Vuillaume
- Département de Biologie, Caribou Ungava, Centre d'Études Nordiques, Université Laval, 1045, Ave. de la Médecine, Québec, QC, G1V 0A6, Canada.
| | - Julien H Richard
- Département de Biologie, Caribou Ungava, Centre d'Études Nordiques, Université Laval, 1045, Ave. de la Médecine, Québec, QC, G1V 0A6, Canada
| | - Sandra Hamel
- Département de Biologie, Université Laval, Québec, QC, G1V 0A6, Canada
| | - Joëlle Taillon
- Ministère des Forêts de la Faune et des Parcs, Québec, QC, G1S 2L2, Canada
| | - Marco Festa-Bianchet
- Département de Biologie, Caribou Ungava, Centre d'Études Nordiques, Université de Sherbrooke, Sherbrooke, QC, J1K 2 R1, Canada
| | - Steeve D Côté
- Département de Biologie, Caribou Ungava, Centre d'Études Nordiques, Université Laval, 1045, Ave. de la Médecine, Québec, QC, G1V 0A6, Canada
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Bonin M, Dussault C, Taillon J, Pisapio J, Lecomte N, Côté SD. Diet flexibility of wolves and black bears in the range of migratory caribou. J Mammal 2023. [DOI: 10.1093/jmammal/gyad002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Abstract
The diet of predators can be highly variable, which is exemplified by their ability to acclimate to a wide range of ecological conditions. Such flexibility in foraging may be a key aspect of their performance in unpredictable environments such as at the edge of the range of a species or where food availability varies greatly in time and space. Gaining information on the diets of predators under such conditions could foster our comprehension of their ecological flexibility and the potential role of predation on the population dynamics of prey. We determined the diet of wolves (Canis lupus) and black bears (Ursus americanus) in northern Québec and Labrador (Canada) within the range of two migratory caribou (Rangifer tarandus) herds: the high-abundance Rivière-aux-Feuilles herd (RFH) and low-abundance Rivière-George herd (RGH). Worldwide, decline in caribou populations has become a concern, stressing the need to better understand the factors involved in these declines, including predation. In northern Québec (RFH range), caribou was the primary year-round prey of wolves while moose (Alces alces) and muskoxen (Ovibos moschatus) were consumed in some sectors. The diet of wolves in northern Labrador (RGH range) varied seasonally, with caribou, moose, and fish as main prey during different periods throughout the year. Black bear diets varied seasonally and regionally. Among the foods we analyzed, caribou was the main source of animal protein for bears in northern Québec and northern Labrador, except during a high abundance of Ungava collared lemming (Dicrostonyx hudsonius). Only bears in northern Québec ate caribou during late summer/fall. Our results highlight the diet flexibility of wolves and black bears in northern food webs, and how their diets change in relation to the distribution and abundance of prey. Our results will help quantify the potential impact of these predators on prey populations in northern systems.
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Affiliation(s)
- Michaël Bonin
- Caribou Ungava, département de biologie, Université Laval , 1045 avenue de la Médecine, Québec City, Québec G1V 0A6 , Canada
- Centre d’études nordiques, Université Laval , 2405 rue de la Terrasse, Québec City, Québec G1V 0A6 , Canada
| | - Christian Dussault
- Caribou Ungava, département de biologie, Université Laval , 1045 avenue de la Médecine, Québec City, Québec G1V 0A6 , Canada
- Direction de l’expertise sur la faune terrestre, l’herpétofaune et l’avifaune, Ministère des Forêts, de la Faune et des Parcs du Québec, 880 chemin Sainte-Foy , Québec City, Québec G1S 4X4 , Canada
| | - Joëlle Taillon
- Caribou Ungava, département de biologie, Université Laval , 1045 avenue de la Médecine, Québec City, Québec G1V 0A6 , Canada
- Direction de l’expertise sur la faune terrestre, l’herpétofaune et l’avifaune, Ministère des Forêts, de la Faune et des Parcs du Québec, 880 chemin Sainte-Foy , Québec City, Québec G1S 4X4 , Canada
| | - John Pisapio
- Caribou Ungava, département de biologie, Université Laval , 1045 avenue de la Médecine, Québec City, Québec G1V 0A6 , Canada
- Wildlife Division, Newfoundland and Labrador Department of Fisheries, Forests and Agriculture , Happy Valley-Goose Bay, Newfoundland and Labrador A0P 1E0 , Canada
| | - Nicolas Lecomte
- Caribou Ungava, département de biologie, Université Laval , 1045 avenue de la Médecine, Québec City, Québec G1V 0A6 , Canada
- Centre d’études nordiques, Université Laval , 2405 rue de la Terrasse, Québec City, Québec G1V 0A6 , Canada
- Chaire de recherche du Canada en écologie polaire et boréale et Centre d’études nordiques, département de biologie, Université de Moncton , 18 avenue Antonine-Maillet, Moncton, New Brunswick E1A 3E9 , Canada
| | - Steeve D Côté
- Caribou Ungava, département de biologie, Université Laval , 1045 avenue de la Médecine, Québec City, Québec G1V 0A6 , Canada
- Centre d’études nordiques, Université Laval , 2405 rue de la Terrasse, Québec City, Québec G1V 0A6 , Canada
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Koltz AM, Gough L, McLaren JR. Herbivores in Arctic ecosystems: Effects of climate change and implications for carbon and nutrient cycling. Ann N Y Acad Sci 2022; 1516:28-47. [PMID: 35881516 PMCID: PMC9796801 DOI: 10.1111/nyas.14863] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Arctic terrestrial herbivores influence tundra carbon and nutrient dynamics through their consumption of resources, waste production, and habitat-modifying behaviors. The strength of these effects is likely to change spatially and temporally as climate change drives shifts in herbivore abundance, distribution, and activity timing. Here, we review how herbivores influence tundra carbon and nutrient dynamics through their consumptive and nonconsumptive effects. We also present evidence for herbivore responses to climate change and discuss how these responses may alter the spatial and temporal distribution of herbivore impacts. Several current knowledge gaps limit our understanding of the changing functional roles of herbivores; these include limited characterization of the spatial and temporal variability in herbivore impacts and of how herbivore activities influence the cycling of elements beyond carbon. We conclude by highlighting approaches that will promote better understanding of herbivore effects on tundra ecosystems, including their integration into existing biogeochemical models, new applications of remote sensing techniques, and the continued use of distributed experiments.
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Affiliation(s)
- Amanda M. Koltz
- Department of BiologyWashington University in St. LouisSt. LouisMissouriUSA,The Arctic InstituteCenter for Circumpolar Security StudiesWashingtonDCUSA,Department of Integrative BiologyUniversity of Texas at AustinAustinTexasUSA
| | - Laura Gough
- Department of Biological SciencesTowson UniversityTowsonMarylandUSA
| | - Jennie R. McLaren
- Department of Biological SciencesUniversity of Texas El PasoEl PasoTexasUSA
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Joly K, Gunn A, Côté SD, Panzacchi M, Adamczewski J, Suitor MJ, Gurarie E. Caribou and reindeer migrations in the changing Arctic. ANIMAL MIGRATION 2021. [DOI: 10.1515/ami-2020-0110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Abstract
Caribou and reindeer, Rangifer tarandus, are the most numerous and socio-ecologically important terrestrial species in the Arctic. Their migrations are directly and indirectly affected by the seasonal nature of the northernmost regions, human development and population size; all of which are impacted by climate change. We review the most critical drivers of Rangifer migration and how a rapidly changing Arctic may affect them. In order to conserve large Rangifer populations, they must be allowed free passage along their migratory routes to reach seasonal ranges. We also provide some pragmatic ideas to help conserve Rangifer migrations into the future.
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Affiliation(s)
- Kyle Joly
- Gates of the Arctic National Park and Preserve, Arctic Inventory and Monitoring Network, National Park Service , 4175 Geist Road, Fairbanks, Alaska, 99709, USA
| | - Anne Gunn
- Salt Spring Island , British Columbia V8K 1V1 Canada
| | - Steeve D. Côté
- Département de biologie, Caribou Ungava & Centre d’études nordiques , Université Laval , Québec (QC), G1V 0A6 , Canada
| | - Manuela Panzacchi
- Norwegian Institute for Nature Research (NINA) , Høgskoleringen 9, NO-7034 Trondheim , Norway
| | - Jan Adamczewski
- Department of Environment and Natural Resources, Government of the Northwest Territories , Yellowknife, Northwest Territories , Canada
| | - Michael J. Suitor
- Fish and Wildlife Branch, Environment Yukon, Yukon Government , Dawson City , Yukon , Canada
| | - Eliezer Gurarie
- Department of Biology , University of Maryland , College Park, Maryland, 20742, USA , and Department of Environmental and Forest Biology, SUNY College of Environmental Science and Forestry , Syracuse , NY 13210
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