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DeCesare NJ, Harris RB, Peterson CJ, Ramsey JM. Prevalence and Mortality of Moose (Alces alces) Infected with Elaeophora schneideri in Montana, USA. J Wildl Dis 2023; 59:748-752. [PMID: 37846918 DOI: 10.7589/jwd-d-22-00075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Accepted: 05/11/2023] [Indexed: 10/18/2023]
Abstract
Elaeophora schneideri is a filarial nematode of North America that occasionally infects aberrant ruminant hosts such as moose (Alces alces). The role E. schneideri plays in clinical morbidity or mortality of moose remains uncertain. We sampled predominantly hunter-killed adult moose (n=127) to characterize the spatial patterns of prevalence and intensity of worms in carotid arteries of moose in Montana. We compared prevalence and intensity of E. schneideri within these moose to a separate sample of adult moose that died of health-related causes (n=34). We found lower prevalence in northwest Montana (0.06) than in the remainder of the state (0.42). We also found both higher prevalence of E. schneideri and higher intensity to be correlated with increased probability of health-related mortality. Our results suggest presence and intensity of E. schneideri correlate with mortality of moose, although the mechanisms of mortality remain uncertain.
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Affiliation(s)
- Nicholas J DeCesare
- Montana Fish, Wildlife and Parks, 3201 Spurgin Road, Missoula, Montana 59804, USA
| | - Richard B Harris
- Montana Fish, Wildlife and Parks, 1420 East Sixth Avenue, Helena, Montana 59620, USA
| | - Collin J Peterson
- Montana Fish, Wildlife and Parks, 490 North Meridian Road, Kalispell, Montana 59901, USA
| | - Jennifer M Ramsey
- Montana Fish, Wildlife and Parks, 1400 South 19th Avenue, Bozeman, Montana 59718, USA
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Struck M, Severud WJ, Chenaux-Ibrahim YM, J. Isaac E, Brown JL, Moore SA, Wolf TM. Refining the moose serum progesterone threshold to diagnose pregnancy. CONSERVATION PHYSIOLOGY 2023; 11:coad003. [PMID: 38026802 PMCID: PMC10660365 DOI: 10.1093/conphys/coad003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 11/25/2022] [Accepted: 01/25/2023] [Indexed: 12/01/2023]
Abstract
Pregnancy determination is necessary for sound wildlife management and understanding population dynamics. Pregnancy rates are sensitive to environmental and physiological factors and may indicate the overall trajectory of a population. Pregnancy can be assessed through direct methods (rectal palpation, sonography) or indicated using hormonal assays (serum progesterone or pregnancy-specific protein B, fecal progestogen metabolites). A commonly used threshold of 2 ng/ml of progesterone in serum has been used by moose biologists to indicate pregnancy but has not been rigorously investigated. To refine this threshold, we examined the relationship between progesterone concentrations in serum samples and pregnancy in 87 moose (Alces alces; 64 female, 23 male) captured from 2010 to 2020 in the Grand Portage Indian Reservation in northeastern Minnesota, USA. Pregnancy was confirmed via rectal palpation (n = 25), necropsy (n = 2), calf observation (n = 25) or characteristic pre-calving behavior (n = 6), with a total of 58 females determined pregnant and 6 not pregnant; 23 males were included to increase the non-pregnant sample size. Using receiver operating characteristic analysis, we identified an optimal threshold of 1.115 ng/ml with a specificity of 0.97 (95% confidence interval [CI] = 0.90-1.00) and a sensitivity of 0.98 (95% CI = 0.95-1.00). Progesterone concentrations were significantly higher in cases of pregnant versus non-pregnant cows, but we did not detect a difference between single and twin births. We applied our newly refined threshold to calculate annual pregnancy rates for all female moose (n = 133) captured in Grand Portage from 2010 to 2021. Mean pregnancy rate during this period was 91% and ranged annually from 69.2 to 100%. Developing a reliable method for determining pregnancy status via serum progesterone analyses will allow wildlife managers to assess pregnancy rates of moose without devoting substantial time and resources to palpation and calf monitoring.
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Affiliation(s)
- Madeline Struck
- Department of Veterinary Population Medicine, University of Minnesota, Saint Paul, MN 55108, USA
| | - William J Severud
- Department of Veterinary Population Medicine, University of Minnesota, Saint Paul, MN 55108, USA
| | - Yvette M Chenaux-Ibrahim
- Department of Biology and Environment, Grand Portage Band of Lake Superior Chippewa, Grand Portage, MN 55605, USA
| | - Edmund J. Isaac
- Department of Biology and Environment, Grand Portage Band of Lake Superior Chippewa, Grand Portage, MN 55605, USA
| | - Janine L Brown
- Smithsonian Conservation Biology Institute, Center for Species Survival, National Zoological Park, Front Royal, VA, 22630, USA
| | - Seth A Moore
- Department of Biology and Environment, Grand Portage Band of Lake Superior Chippewa, Grand Portage, MN 55605, USA
| | - Tiffany M Wolf
- Department of Veterinary Population Medicine, University of Minnesota, Saint Paul, MN 55108, USA
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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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Burkholder BO, Harris RB, DeCesare NJ, Boccadori SJ, Garrott RA. Winter habitat selection by female moose in southwestern Montana and effects of snow and temperature. WILDLIFE BIOLOGY 2022. [DOI: 10.1002/wlb3.01040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Braden O. Burkholder
- Dept of Ecology, Montana State Univ. Bozeman MT USA
- Montana Natural Heritage Program Helena MT USA
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Mueller M, Johnson CJ, McNay RS. Influence of maternity penning on the success and timing of parturition by mountain caribou (Rangifer tarandus caribou). CAN J ZOOL 2022. [DOI: 10.1139/cjz-2021-0144] [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
Invasive conservation actions that require the capture and handling of individual animals are common, but the implications for both survival and reproduction are often not studied. Across North America, most populations of woodland caribou (Rangifer tarandus caribou Gmelin, 1788) are Threatened or Endangered. Maternity penning, where pregnant females are held in an enclosure until the calf is less vulnerable to predation, is one conservation action that is designed to increase population growth. Few studies have reported the influence of maternity penning on the occurrence or timing of parturition and the implications for reproduction. We quantified parturition success and dates of penned and free-ranging caribou within the Klinse-Za population of caribou found across east-central British Columbia, Canada. Parturition dates were identified using daily observations for penned caribou (n=41) and estimated dates for free-ranging caribou (n=27) generated using statistical modelling of GPS collar data. We related parturition outcomes to a range of ecological and environmental variables. We found that the occurrence and date of parturition did not differ between penned and free-ranging caribou. For all monitored animals there was an earlier calving date during years of higher snowfall and warmer winter weather. Our results suggested that maternity penning, a potentially invasive conservation action, did not increase or decrease the probability or date of parturition for this study population.
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Affiliation(s)
- Mariah Mueller
- University of Northern British Columbia, 6727, Prince George, Canada
| | - Chris J. Johnson
- University of Northern British Columbia, 6727, Department of Ecosystem Science and Management, Prince George, Canada
| | - R. Scott McNay
- Wildlife Infometrics, Inc., Research, Mackenzie, British Columbia, Canada
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Cook JG, Kelly AP, Cook RC, Culling B, Culling D, McLaren A, Larter NC, Watters M. Seasonal patterns in nutritional condition of caribou (Rangifer tarandus) in the southern Northwest Territories and northeastern British Columbia, Canada. CAN J ZOOL 2021. [DOI: 10.1139/cjz-2021-0057] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Evaluating nutritional condition provides insights of nutritional influences on wildlife populations. We sampled three measures of condition — body fat, body mass, and loin thickness — of adult female caribou (Rangifer tarandus (Linnaeus, 1758)) in boreal settings in the Northwest Territories (NT), Canada, in December and March, 2016–2018, and in mountain and boreal settings in British Columbia (BC), Canada, in December and February, 2014–2015. We evaluated the effect of calf-rearing on condition in December, compared influences of summer–autumn versus winter on condition over winter, and developed an annual profile of nutritional condition with estimates from caribou dying in summer. Mean December body fat was 8.4% in females with calves and 11.4% in females without calves, demonstrating the influence of lactation on condition. Over winter, nutritional condition did not decline in northeastern BC and it declined slightly in NT: body fat by 0.55 percentage points, mass by 2.8 kg, and loin thickness did not change. Body fat peaked in December, changed little over winter, but declined to a minimum by early summer, temporally coinciding with elevated rates of adult female mortality. Consistent with those of other ungulate studies worldwide, our findings suggest a need to focus on nutritional limitations operating in late spring through early autumn.
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Affiliation(s)
- John G. Cook
- Forestry and Range Sciences Laboratory, National Council for Air and Stream Improvement, 1401 Gekeler Lane, La Grande, OR 1401 Gekeler Lane, USA
| | - Allicia P. Kelly
- Department of Environment and Natural Resources, Government of the Northwest Territories, Box 900, Fort Smith, NT X0E 0P0, Canada
| | - Rachel C. Cook
- Forestry and Range Sciences Laboratory, National Council for Air and Stream Improvement, 1401 Gekeler Lane, La Grande, OR 1401 Gekeler Lane, USA
| | - Brad Culling
- Diversified Environmental, Box 6263, Fort St. John, BC V1J 4X7, Canada
| | - Diane Culling
- Diversified Environmental, Box 6263, Fort St. John, BC V1J 4X7, Canada
| | - Ashley McLaren
- Wildlife Research and Monitoring Section, Ontario Ministry of Natural Resources and Forestry, Peterborough, ON K9L 1Z8, Canada
| | - Nicholas C. Larter
- Department of Environment and Natural Resources, Government of the Northwest Territories, Fort Simpson, NT X0E 0N0, Canada
| | - Megan Watters
- British Columbia Ministry of Forests, Lands, Natural Resource Operations and Rural Development, Fort St. John, BC V1J 6M7, Canada
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Cook RC, Crouse JA, Cook JG, Stephenson TR. Evaluating indices of nutritional condition for caribou (Rangifer tarandus): which are the most valuable and why? CAN J ZOOL 2021. [DOI: 10.1139/cjz-2020-0149] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Body composition studies are critical for evaluating the accuracy of nutritional condition indices for predicting body components. We evaluated >40 indices of nutritional condition for caribou (Rangifer tarandus (Linnaeus, 1758)) using 29 female caribou captured from three populations in Alaska (USA) that ranged in condition from 2.3% to 11.2% ingesta-free body fat (IFBF) and 6 captive female caribou that ranged in condition from 8.1% to 26.0% IFBF. Estimates of body fat, protein, and gross energy were regressed against each index of nutritional condition. Generally, indices with linear or slightly curvilinear relations to body fat and those based on multiple fat depots were the most accurate in predicting nutritional condition and the most useful over the full range of nutritional condition. A scaledLIVINDEX (a combination of subcutaneous fat thickness and a condition score), CONINDEX (a combination of kidney fat and marrow fat), and a subset of the Kistner score (pericardium and kidneys only) had the strongest relationship with body fat (r2 > 0.86) and were useful over the entire range of nutritional condition. If used properly and with adequate training, indices of nutritional condition can be a critical tool for understanding the severity and seasonality of nutritional limitations in wild caribou populations.
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Affiliation(s)
- Rachel C. Cook
- National Council for Air and Stream Improvement, Forestry and Range Sciences Laboratory, 1401 Gekeler Lane, La Grande, OR 97850, USA
| | - John A. Crouse
- Kenai Moose Research Center, Alaska Department of Fish and Game, 43961 Kalifornsky Beach Road, Suite B, Soldotna, AK 99669, USA
| | - John G. Cook
- National Council for Air and Stream Improvement, Forestry and Range Sciences Laboratory, 1401 Gekeler Lane, La Grande, OR 97850, USA
| | - Thomas R. Stephenson
- Sierra Nevada Bighorn Sheep Recovery Program, California Department of Fish and Wildlife, 787 North Main Street, Suite 220, Bishop, CA 93514, USA
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