Productivity and Early Calf Survival in the Porcupine Caribou Herd

Whitten, Kenneth R.; Garner, Gerald W.; Mauer, Francis J.; Harris, Richard B.

doi:10.2307/3808814

Cited by 104 publications

(90 citation statements)

References 16 publications

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“…Huggard (1993) found that wolf predation on elk increased from 1 animal every 5.4 days with no snow, to 1 every 1.1 days, when snow depth reached 60 cm. Many studies have suggested that wolf predation may limit caribou populations in the boreal forest ecosystem (Edmonds, 1988;Written et al, 1992;. The forest dwelling woodland caribou (Rangifer tarandus caribou) has declined across North America (Mallory & Hillis, 1998) and is officially listed as "threatened" by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC, 2002).…”

Section: Lake Abitibimentioning

confidence: 99%

Range size and seasonal movement for female woodland caribou in the boreal forest of northeastern Ontario

Brown¹,

Mallory²,

Rettie³

2003

Ran

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A preliminary examination was conducted of range size and distribution of female woodland caribou (Rangifer tarandus caribou) in northeastern Ontario. Annual and seasonal ranges were calculated using satellite telemetry data collected for 30 female caribou between 1998 and 2001. The mean annual home range size of collared females was 4026 km 2 . Seasonal ranges varied in size depending on time of year (P<0.05). Calving and summer ranges were significantly smaller than autumn and late winter ranges. Early winter ranges were significantly larger than calving ranges and small¬ er than late winter ranges. Overall, range sizes of female woodland caribou in northeastern Ontario were larger than those reported for caribou in other Boreal Forest regions across Canada.

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Section: Lake Abitibimentioning

confidence: 99%

Range size and seasonal movement for female woodland caribou in the boreal forest of northeastern Ontario

Brown¹,

Mallory²,

Rettie³

2003

Ran

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“…According to Linnell et al (1995) predation generally comprises the major share of the total mortality of juvenile ungulates. Many studies of reindeer/caribou have also demonstrated that calf mortality is usually highest during the rst days and weeks after calving and then decreases considerably during summer and autumn (see Eloranta & Nieminen, 1986;Whitten et al, 1992;Adams et al, 1995;Norberg et al, 2005).…”

Section: Discussionmentioning

confidence: 99%

“…Mortality during the rst summer is an important factor in the population dynamics of many reindeer (Rangifer tarandus tarandus) and caribou (R. tarandus) herds, and predation is usually suspected as the primary cause of mortality (Miller & Broughton, 1974;Page, 1985;Mahoney et al, 1990;Skogland, 1991;Whitten et al, 1992;Adams et al, 1995;Valkenburg et al, 2004). Apart from many herding activities and supplementary feeding during winter months, reindeer are free-ranging most of the year.…”

Section: Introductionmentioning

confidence: 99%

Calf mortality of semi-domesticated reindeer (Rangifer tarandus tarandus) in the Finnish reindeer-herding area

Nieminen¹,

Norberg²,

Maijala³

2013

Ran

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During 1999-2008 calf mortality was studied in six reindeer-herding cooperatives in Northern Finland, where 3942 semi-domesticated reindeer (Rangifer tarandus tarandus) calves were equipped with radio mortality collars. e calves were weighed and earmarked mostly at 2-5 days of age, or at 2-8 weeks of age. Altogether 460 dead radio-collared calves were found from calving in May until winter round-ups in October-January. In northern mountain herding cooperatives, the average mortality of calves varied between 7-12%. On average, 39-54% of calves found dead were attributed to predation. Golden eagles killed 0-3.5% of calves in di erent years and areas in Ivalo and Käsivarsi cooperatives. Golden eagles were responsible for 33-43% of the cases and 84-93% of all identi ed predation. Most calves killed by golden eagles were found in July-August and in open areas. Calves killed by golden eagles were signi cantly (P<0.01) lighter than those not predated. No predation occurred in the Poikajärvi cooperative, but the annual mortality of calves varied between 0-35% in cooperatives near the Russian border. In Oivanki cooperative brown bears killed on average 2% of the radio-collared calves. Most predation (87%) occurred at the end of May and in early June. In the Kallioluoma cooperative, predator-killed calves found comprised 53% and wolf-killed 45%. Predation was 70% of total mortality in the Halla cooperative, and predation by wolf, bear, lynx and wolverine comprised on average 38%, 20%, 9% and 2.3%, respectively. e sex and pelt color did not signi cantly a ect survival of calves. Birth weight of calves killed by bears was signi cantly (P<0.01) lighter than those not killed, but those calves killed by lynxes were signi cantly (P<0.05) heavier than that survived. Bears killed calves mainly

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“…Hibernating brown (Ursus arctos) and black bears (U. americanus) have no affect on the Porcupine Herd on winter range, but brown bears are effective predators on summer range. Golden eagles (Aquila chryseatos) are relatively common near the primary calving areas and are adept at taking young calves (Whitten et al, 1992a). Wolverines (Gulo gulo) and lynx (Lynx canadensis) occur widely but have little effect on Porcupine caribou.…”

Section: The Porcupine Herd and Its Environmentmentioning

confidence: 99%

Ecology of the Porcupine caribou herd

Whitten

1996

Ran

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Abstract:Researchers have described general patterns of population regulation that fit most caribou (Rangifer tarandus) herds. Nevertheless, specific factors operating on particular populations vary greatly, and efforts to categorize herds according to the general patterns often lead to confusion. It is difficult for biologists to attempt to describe population dynamics in terms of density relationships for wide-ranging arctic caribou such as the Porcupine Herd. In these herds density varies as a function of dispersal and erratic movement patterns and is not simply the number of caribou divided by a fixed range area. Density is also a poor surrogate for resource availability per individual caribou because climatic factors affect forage and/or access to forage independendy of caribou numbers. Thus classic signs of nutritional stress such as delayed puberty, reduced productivity, and winter starvation can occur when a population is small as well as large and do not necessarily denote food competition brought on by high density, per se. Nutritional stress and exacerbated predation due to adverse weather conditions occasionally cause the Porcupine Herd to decline, and limiting factors such as poor nutrition, predation, harvest, accidents, and disease act in combination to keep herd growth rates low during periods of good weather. Adverse weather setbacks occur frequently, and the herd remains within a fairly restricted range of densities over long time periods. There is no true density dependent regulation and no equilibrium in this system.

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Productivity and Early Calf Survival in the Porcupine Caribou Herd

Cited by 104 publications

References 16 publications

Range size and seasonal movement for female woodland caribou in the boreal forest of northeastern Ontario

Range size and seasonal movement for female woodland caribou in the boreal forest of northeastern Ontario

Calf mortality of semi-domesticated reindeer (Rangifer tarandus tarandus) in the Finnish reindeer-herding area

Ecology of the Porcupine caribou herd

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