Reproduction in wild reindeer in Norway

Reimers, Eigil

doi:10.1139/z83-026

Cited by 126 publications

(97 citation statements)

References 7 publications

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“…Data on snow conditions during winter, changes in energetic reserves by individuals within and among years, and estimates of calf productivity will become increasingly useful for predicting population trajectories as climatic factors and vegetative parameters become more variable (Lenart et al, 2002;Adams, 2005). Maternal body mass affects the probability of pregnancy in autumn (Reimers, 1983;Cameron et al, 1993;Cameron & Ver Hoef, 1994) as well as calf survival through summer (Eloranta & Nieminen, 1986;Gustafson et al, 1998). Specific components (i.e., fat and protein) of body mass, however, are better predictors of pregnancy (Gerhart et al, 1996a;Ouellet et al, 1997).…”

Section: Discussionmentioning

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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Section: Discussionmentioning

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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“…Hence, some of the birth date delay indicated in Table 4 may be compensated by smaller birth weights. However, it is possible that the apparent age effect in reality is a body weight or body composition effect (Reimers, 1983b;Ropstad et al, 1991). Being in a growth phase, it is conceivable that yearlings, and in particular calves meet the weight or fat:lean ratio needed for ovulation (Ropstad et al, 1991) later than the older females.…”

Section: Discussionmentioning

confidence: 99%

Calving time and foetus growth among wild reindeer in Norway

Reimers

2002

Ran

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Mean calving dates among 7 wild reindeer (Rangifer t. tarandus) herds in southern Norway varied between the 6th and the 27th of May. Ln transformed foetus weights relate linearly to ln age in days. Regression analyzes based upon 225 days pregnancy predicts birth wet weights between 4600 and 7500 g in the different areas and years. At 130 days, foetus weights varied between 547 and 746 g (x=681, standard deviation s=63) in all areas and years, indicating that foetus growth up to this size is independent of mothers body weight or condition. During the remaining 95 days of pregnancy, very poor body condition, reflected in dressed weights, resulted in slower foetus growth and smaller regression estimated birth weights. The foetus weight variation recorded at similar dates within areas and sampling years indicates a dispersed breeding time mostly within two ovulations. A small sample of foetuses from pregnant yearlings and calves indicate that these cohorts conceive later than 2 yr + females. Assuming similar foetus growth pattern among all female age cohorts within areas, yearlings conceive around 1 week later and calves (in Ottadalen) more than 3 weeks later than 2 + yr olds.

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“…Up until 2005 NINA maintained that their recruitment rates estimated calves per 100 females 1+ yr and that they were able to exclude yearling males from their estimates (see Reimers, 2006). Females in this area normally breed for the rst time as yearlings (their second autumn) and give birth as 2-year-olds (Reimers, 1983). As our model comparisons focus on recruitment and estimated number of yearlings year N-1 converted to 2-year-olds year N, and an assumption of similar survival of yearlings from year to year, we do not vary the yearling mortality as a factor in the model.…”

Section: Study Areamentioning

confidence: 99%

The Hardangervidda wild reindeer herd: a problematic management history

Bjerketvedt¹,

Reimers²,

Parker³

et al. 2014

Ran

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e unique and internationally important wild reindeer Rangifer tarandus herd on the Hardangervidda plateau of southern Norway has shown frequent and extreme uctuations in harvest numbers for the past 60 years, despite considerable e ort to stabilize the herd size at a winter carrying capacity of 9000 -12 000 animals . In the absence of large mammalian predators, herd size is managed through hunting. Here we attempt to unravel the causes of the management problems related to this population by examining the relative roles of historical, biological and managementrelated processes. From 1900 -1950 the population remained mainly low due to a combination of generous harvest quotas, poaching and competition from domestic reindeer. From 1950 -2012 three extreme harvest peaks of between 4500 -9500 animals occurred, followed by three equally extreme troughs including two shorter periods of total protection.is extreme harvest uctuation contrasts with the estimated annual harvest of 2300 -3000 needed to stabilize the winter herd between 9000 -12 000 animals. We conclude that this population has been di cult to manage mainly because of 1) a management based on frequently unreliable population data on herd size (especially before 2001), 2) lack of in depth analyses and evaluation of both recruitment and sex and age composition and 3) a low and highly variable harvest success (harvest/quota) due mainly to poor hunter mobility, a disadvantage when reindeer must be harvested from large ocks that constantly move upwind, seeking refuge on small areas with few hunters. More reliable population data to create better harvest models plus increased hunter mobility are necessary to attain a more sustainable herd size, implying an improvement of the current herd survey methodology available to local reindeer boards. Finally, a critical and independent evaluation of the scienti c methodology employed to study and manage this herd is needed.

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Reproduction in wild reindeer in Norway

Cited by 126 publications

References 7 publications

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

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

Calving time and foetus growth among wild reindeer in Norway

The Hardangervidda wild reindeer herd: a problematic management history

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