Science

The severity of recent declines of barren-ground caribou (Rangifer tarandus groenlandicus) across the central Canadian Arctic has led to harvest restrictions and concerns about population recovery. Wolves (Canis lupus) are the main predator of barren-ground caribou; however, the extent that wolves influence the decline and recovery of caribou herds is unknown. Such uncertainty confounds management  responses (e.g., reducing harvest, predator control).

My study focused on investigating wolf-caribou dynamics on the summer range of the Bathurst caribou herd. I used a multi-scale study design to investigate the behavioural and population responses of wolves during a severe decline in caribou numbers. The summer ranges of the Bathurst herd contracted north towards their calving grounds as the herd declined and caribou remained farther from the summer territories of wolves for relatively longer portions of the denning period.

The genetic variability of gray wolves (Canis lupus) from northwestern Canada was assessed through starch-gel electrophoresis. Of 27 protein systems examined, 25, representing 37 presumptive loci, were consistently scorable; 7 proteins (5 were consistently scorable) exhibited polymorphism. The level of heterozygosity (3.0%) was medial relative to values reported for natural populations of Carnivora and high relative to values reported for natural populations of canids. An overall pattern of few deviations from Hardy-Weinberg expectations and some spatial heterogeneity was observed.

Kelsall, J. P. 1968. The migratory barren-ground caribou of Canada. Canadian Wildlife Service Monograph, 3:1-340. Book  Copyright protected (A copy is available to review, at the Legislative Library.)

The nature and severity of a bullet wound depend on the characteristics of the bullet and of the tissues through which it travels. In addition to the mass and velocity of the bullet, its orientation and whether it fragments or deforms affect the nature of the wound. Two major mechnaisms of wounding are described: crushing and stretching of tissue. Understanding the mechanisms by which bullets disrupt tissue can help physicians to evaluate and treat wounds.

An aerial survey with about 5% coverage of the northeastern mainland, Northwest Territories (342 000 km²) was conducted 5-12 May 1983. We estimated there were 120,000 + 13,900 caribou (0.35 + 0.041caribou km²) in the studyarea. Mean caribou group size ranged from 6 to 11 among nine strata and was correlated (r= 0.81) with stratum caribou density. We found four regions of high caribou density.

Most wolves (Canis lupus) on migratory caribou (Rangifer tarandus) ranges in the Northwest Territories den near the tree line, the northern limit of tree growth. Sixty percent of the 209 dens that we located were within 50 km of the tree line, an area representing only 25 % of the caribou range. Den density in the forest was significantly lower than expected if dens were randomly dispersed. Within the tundra zone wolves did not show any preference for denning near caribou calving grounds.

We studied the dynamics of a wolf (Canis lupus) population recovering from intensive reduction in the Finlayson Lake area, Yukon, Canada. Within 6 years, numbers increased from 29 wolves, then stabilized at 245. The colonization of vacant territories by young wolf pairs was the primary mechanism of early population recovery. Reproduction and a low dispersal rate increased pack size in later years, and pack splitting allowed dispersing wolves to remain near natal packs.

Large migratory catibou {Rangifer tarandus) herds in the Arctic tend to be cyclic, and population trends ate mainly driven by changes in forage or weather events, not by predation. We estimated daily kill rate by wolves on adult caribou in winter, then constructed a time and space dependent model to estimate annual wolf (Canis lupus) predation rate (P_annual) on adult Porcupine catibou.

Movement patterns of highly mobile animals can reveal life history strategies and ecological relationships. We hypothesized that wolves (Canis lupus) would display similar movement patterns as their prey, barrenground caribou (Rangifer tarandus groenlandicus), and that movements of the two species would co-vary with season. We tested for interspecific movement dynamics using animal locations from wolves and caribou monitored concurrently from mid-October to June, across the Northwest Territories and Nunavut, Canada.