The effects of food and maternal conditions in fetal growth and size in wild reindeer

Skogland, Terje

doi:10.7557/2.4.2.501

Cited by 108 publications

(134 citation statements)

References 18 publications

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“…e method currently in use by NINA (Jordhøy et al, 1996;Jordhøy et al, 2003) for determination of early calf mortality or calf production is counting calves and females 1+ years in June/ July from aerial photographs (Skogland, 1984a(Skogland, , 1985aAndersen et al, 2005). is method is based on the assumption that the number of yearling males is negligible in the post-calving reindeer groups and that the calf/female ratio re ects the annual recruitment, an assumption that has been tested and found to underestimate calf production (Reimers, 2006).…”

Section: Discussionmentioning

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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Section: Discussionmentioning

confidence: 99%

The Hardangervidda wild reindeer herd: a problematic management history

Bjerketvedt¹,

Reimers²,

Parker³

et al. 2014

Ran

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“…However, it is also likely that summer range is limiting in the NAP because natality in June, and weight and con¬ dition of calves in October has also been low, and these factors are generally considered to be more affected by summer nutrition than by winter nutri¬ tion (cf. Skogland, 1984;Reimers, 1997).…”

Section: Discussionmentioning

confidence: 99%

Population dynamics of caribou herds in southwestern Alaska

Valkenburg¹,

Sellers²,

Squibb³

et al. 2003

Ran

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The five naturally occurring and one transplanted caribou (Rangifer tarandus granti) herd in southwestern Alaska composed about 20% of Alaska's caribou population in 2001. All five of the naturally occurring herds fluctuated considerably in size between the late 1800s and 2001 and for some herds the data provide an indication of long-term periodic (40-50 year) fluctuations. At the present time, the Unimak (UCH) and Southern Alaska Peninsula (SAP) are recovering from population declines, the Northern Alaska Peninsula Herd (NAP) appears to be nearing the end of a protracted decline, and the Mulchatna Herd (MCH) appears to now be declining after 20 years of rapid growth. The remaining naturally occurring herd (Kilbuck) has virtually disappeared. Nutrition had a significant effect on the size of 4-monthold and 10-month-old calves in the NAP and the Nushagak Peninsula Herd (NPCH) and probably also on population growth in at least 4 (SAP, NAP, NPCH, and MCH) of the six caribou herds in southwestern Alaska. Predation does not appear to be sufficient to keep caribou herds in southwestern Alaska from expanding, probably because rabies is endemic in red foxes (Vulpes vulpes) and is periodically transferred to wolves (Canis lupus) and other canids. However, we found evidence that pneumonia and hoof rot may result in significant mortality of caribou in southwestern Alaska, whereas there is no evidence that disease is important in the dynamics of Interior herds. Cooperative conservation programs, such as the Kilbuck Caribou Management Plan, can be successful in restraining traditional harvest and promoting growth in caribou herds. In southwestern Alaska we also found evidence that small caribou herds can be swamped and assimilated by large herds, and fidelity to traditional calving areas can be lost.

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“…This sequence increased the risk of preda¬ tion but allowed maximum energy intake in the last trimester of pregnancy. Calf survival at parturition has been shown to be correlated with birth weight Adams et al, 1995) and Skogland (1984) pro¬ posed that forage at this stage of the fetus growth was critical. In 1992, the year of the latest phenolo¬ gy in Ungava since weath¬ er records have been kept at Schefferville (early 1950s), the calves born were extremely small (Couturier,unpubl.…”

Section: Maymentioning

confidence: 99%

Predation risk and optimal foraging trade-off in the demography and spacing of the George River Herd, 1958 to 1993

Bergerud¹,

Luttich²

2003

Ran

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The behavior options of feeding animals lie on a continuum between energy maximization and minimization of predation risk. We studied the distribution, mobility, and energy budgets of the George River herd, Ungava from 1974 to 1993. We arranged the annual cycle into 6 phases where we argue that the importance between the priorities of opti¬ mal foraging and predation risk change between periods. At calving, risk is more important than foraging for females but males take more risk to optimally forage. During the mosquito season, insect avoidance takes priority over risk and for¬ aging. Optimal foraging takes precedent over risk in the late summer and fall and it is at this time that the herd expanded its range relative to numbers and forage abundance. In the winter (December to mid-March) animals sought restrict¬ ed localized ranges with low snow cover to reduce predation risk. The spring migration of females may have increased risk during the interval the females were moving back to the tundra to give birth to their neonates on the low risk calv¬ ing ground. In May, females sought early greens near treeline, which may have increased risk in order to provide maxi¬ mum nutrition to their fetuses in the last weeks of pregnancy. The ancestors of the George River Herd during the Pleistocene, 18 000 yr. BP may have reduced predation risk by spacing-out in the Appalachian Mountains, removed from the major specie of the megafauna in the lowlands. With global warming, it is argued the major problem for caribou will be increased wolf predation rather than changing forage and nutritional regimes. It is essential that First Nation residents of the North maintain their option to manage wolf numbers if excessive predation in the future adversely affects the migratory herds of the Northwest Territories and Ungava.

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The effects of food and maternal conditions in fetal growth and size in wild reindeer

Cited by 108 publications

References 18 publications

The Hardangervidda wild reindeer herd: a problematic management history

The Hardangervidda wild reindeer herd: a problematic management history

Population dynamics of caribou herds in southwestern Alaska

Predation risk and optimal foraging trade-off in the demography and spacing of the George River Herd, 1958 to 1993

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