Detection of Early Pregnancy in Caribou: Evidence for Embryonic Mortality

Russell, Daniel M.; Gerhart, K. L.; White, Robert G.; Wetering, D. van de

doi:10.2307/3802559

Cited by 66 publications

(42 citation statements)

References 26 publications

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“…The linkages among nutrition, body composition and reproduc¬ tive performance in ungulates, particularly caribou (Rangifer tarandus), are well documented (White & Trudell, 1980a;Albon et al, 1986;Adamczewski et al, 1987;Cameron & ver Hoef, 1994;1 Poster title «Modelling caribou response to seasonal and long-term changes in vegetation: II Estimating seasonal changes in forage quality*. Russell et al, 1998). For this reason, interpretation or prediction of caribou population dynamics under changing environmental conditions needs to be based on a solid understanding of quality, avail¬ ability and use of forage resources.…”

Section: Introductionmentioning

confidence: 99%

Variations in plant forage quality in the range of the Porcupine caribou herd

Johnstone

Russell²,

Griffith

2002

Ran

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).Abstract: Understanding potential impacts of vegetation change on caribou energetics requires information on varia¬ tions in forage quality among different plant types and over time. We synthesized data on forage quality (nitrogen, neutral detergent fiber and dry matter digestibility) for 10 plant growth forms from existing scientific literature and from field research in the Arctic National Wildlife Refuge, Alaska. These data describe forage quality of plant species in habitats found within the summer and winter range of the Porcupine caribou herd in northwestern Canada and northern Alaska, U.S.A. We compared mean levels of summer forage quality among growth forms and, where possi¬ ble, estimated seasonal changes in forage quality. Preferred forage groups (deciduous shrubs, forbs, and cottongrass flowers) had higher nitrogen and digestibility, and lower fiber content, than other growth forms. Nitrogen concen¬ tration in green biomass peaked at the onset of the growing season in forbs and deciduous shrubs, whereas graminoids reached peak nitrogen concentrations approximately 15-30 days after growth initiation. In vitro dry matter digestibil¬ ity (IVDMD) and concentration of neutral detergent fiber (NDF) of green biomass differed among growth forms, but did not show strong seasonal changes. IVDMD and NDF concentrations were correlated with nitrogen concentrations in studies that had paired sampling.

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Section: Introductionmentioning

confidence: 99%

Variations in plant forage quality in the range of the Porcupine caribou herd

Johnstone

Russell²,

Griffith

2002

Ran

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“…At a broad scale, we predicted that estimated calving and neonatal survival rates would differ when compared with caribou in other regions because of local differences in plant phenology (Stoner et al 2016), climatic conditions (Griffin et al 2011), predator regimes (Linnell et al 1995), hunter harvest (Brown 2011), and population density (Wang et al 2009), but we wanted to determine whether our estimated rates of calving and neonatal survival fell within the range reported across caribou herds in five other regions (Adams et al 1995;Jenkins and Barten 2005;Gustine et al 2006;Pinard et al 2012;DeMars et al 2013). We did not compare our estimated calving rates to pregnancy rates that are widely reported (Bergerud 1980;Gustine et al 2007;Pachkowski et al 2013) because they have the potential to overestimate calving rates , as some caribou can undergo embryonic mortality during pregnancy (Russell et al 1998).…”

Section: Introductionmentioning

confidence: 99%

Seeking sanctuary: the neonatal calving period among central mountain woodland caribou (Rangifer tarandus caribou)

Nobert¹,

Milligan²,

Stenhouse³

et al. 2016

Can. J. Zool.

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Woodland caribou (Rangifer tarandus caribou (Gmelin, 1788)) populations have declined throughout their range. With the goal of better understanding habitat selection and fidelity during the neonatal calving period (0-4 weeks), we applied a noninvasive method that estimates calving events and subsequent survival based on changes in movement rates among GPS-collared female caribou. We examined a long-term GPS-collar data set (1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013)(2014) collected from 81 adult female caribou in two central mountain herds in Alberta and British Columbia, Canada. Although we were unable to validate our results with aerial surveys and pregnancy tests, our estimates of parturition rates, survival rates, calving dates, and habitat selection were consistent with previous studies. We identified 83 calving sites. Female caribou selected calving sites and postparturition habitat on high-elevation ridgetops with gradual slopes and avoided anthropogenic linear features. Female caribou displayed low fidelity to interannual calving ranges with a mean distance of 8.7 km between calving ranges. Fidelity was lower in areas with high seismic-line density. Conservation of high-elevation habitat with limited anthropogenic disturbance is likely to provide the greatest benefit to central mountain caribou during the neonatal calving period, and represents a potential management strategy for population recovery efforts.

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“…Reproductive status during winter may be indicative of body condition in autumn (Cameron et al, 1993). Animals with very low body fat commonly do not come into estrus (Dauphiné, 1976;Thomas & Kiliaan, 1998) or, more rarely, do not carry fetuses to term (Dauphiné, 1976;Russell et al, 1998). Non-pregnant caribou also may have lower body mass than pregnant individuals (Cameron & Ver Hoef, 1994).…”

Section: Introductionmentioning

confidence: 99%

“…Caribou were not immobilized for capture, rather we captured individuals with a net-gun (Rongstad & McCabe, 1984) from a helicopter (Bell Jet Ranger II-206B) and 'hobbled' them with leather restraints. Blood samples (approx 10 ml) were taken to determine reproductive condition of caribou via serum progesterone concentrations (Prairie Diagnostics Services, Saskatoon, SK, Canada; Russell et al, 1998). We estimated thickness (cm) of rump fat using a portable ultrasound machine (Medison Sonovet 600 with variable 4-6 MHz linear probe, Universal Medical Systems Ltd, Bedford Hills, NY, USA) as outlined in Stephenson et al (1998) with the location for measurements provided by T.…”

Section: Introductionmentioning

confidence: 99%

Using ultrasound measurements of rump fat to assess nutritional condition of woodland caribou in northern British Columbia, Canada

Gustine

Parker

Heard

2007

Ran

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Absttact: Body reserves (fat and protein) of cervids are important to the reproductive success of individuals, and therefore may limit productivity of populations. We used a portable ultrasound machine to measure thickness of rump fat for 39 woodland caribou (Rangifer tarandus caribou) captured in the winters (January-February) of 2003 and 2004. We compared thickness of rump fat between pregnant and non-pregnant individuals in the Besa-Prophet drainage of northern British Columbia, Canada. Thirty-eight of the 39 females captured in British Columbia were adults and 34 of the adult caribou were pregnant (89.5 ± 5.1%, x -± binomial SE). Pregnant individuals had more rump fat (0.60 ± 0.067 cm) than nonpregnant animals (0.20 ± 0.029 cm). Recognizing that deposition and mobilization of fat vary with age and possibly across the winter season, ultrasonography can be used as a non-invasive technique in the field to assist in estimating body fat of caribou.

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Detection of Early Pregnancy in Caribou: Evidence for Embryonic Mortality

Cited by 66 publications

References 26 publications

Variations in plant forage quality in the range of the Porcupine caribou herd

Variations in plant forage quality in the range of the Porcupine caribou herd

Seeking sanctuary: the neonatal calving period among central mountain woodland caribou (Rangifer tarandus caribou)

Using ultrasound measurements of rump fat to assess nutritional condition of woodland caribou in northern British Columbia, Canada

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