scholarly journals Woodland caribou persistence and extirpation in relic populations on Lake Superior

Rangifer ◽  
2007 ◽  
Vol 27 (4) ◽  
pp. 57 ◽  
Author(s):  
Arthur T. Bergerud ◽  
W. J. Dalton ◽  
H. Butler ◽  
L. Camps ◽  
R. Ferguson
Keyword(s):  
North America ◽  
Rangifer Tarandus ◽  
Lake Superior ◽  
Continuous Distribution ◽  
Adult Survival ◽  
Late Winter ◽  
Woodland Caribou ◽  
Wolf Predation ◽  
The Mean ◽  
Crucial Test

Extended: The hypothesis was proposed that woodland caribou (Rangifer tarandus caribou) in North America had declined due to wolf predation and over-hunting rather than from a shortage of winter lichens (Bergerud, 1974). In 1974, two study areas were selected for testing: for the lichen hypothesis, we selected the Slate Islands in Lake Superior (36 km2), a closed canopy forest without terrestrial lichens, wolves, bears, or moose; for the predation hypothesis, we selected the nearby Pukaskwa National Park (PNP) where terrestrial lichens, wolves, bears, and moose were present. Both areas were monitored from 1974 to 2003 (30 years). The living and dead caribou on the Slates were estimated by the ‘King census’ strip transect (mean length 108±9.3 km, extremes 22-190, total 3026 km) and the Lincoln Index (mean tagged 45±3.6, extremes 15-78). The mean annual population on the Slate Islands based on the strip transects was 262±22 animals (extremes 104-606), or 7.3/km2 (29 years) and from the Lincoln Index 303±64 (extremes 181-482), or 8.4/km2 (23 years). These are the highest densities in North America and have persisted at least since 1949 (56 years). Mountain maple (Acer spicatum) interacted with caribou density creating a record in its age structure which corroborates persistence at relatively high density from c. 1930. The mean percentage of calves was 14.8±0.34% (20 years) in the fall and 14.1±1.95% (19 years) in late winter. The Slate Islands herd was regulated by the density dependent abundance of summer green foods and fall physical condition rather than density independent arboreal lichen availability and snow depths. Two wolves (1 wolf/150 caribou) crossed to the islands in 1993-94 and reduced two calf cohorts (3 and 4.9 per cent calves) while female adult survival declined from a mean of 82% to 71% and the population declined ≈100 animals. In PNP, caribou/moose/wolf populations were estimated by aerial surveys (in some years assisted by telemetry). The caribou population estimates ranged from 31 in 1979 to 9 in 2003 (Y=1267 - 0.628X, r=-0.783, n=21, P<0.01) and extirpation is forecast in 2018. Animals lived within 3 km of Lake Superior (Bergerud, 1985) with an original density of 0.06/km2, similar to many other woodland herds coexisting with wolves (Bergerud, 1992), and 100 times less than the density found on the Slate Islands. The mean moose population was 0.25±0.016/km2 and the wolf population averaged 8.5±0.65/1000 km2. Late winter calf percentages in PNP averaged 16.2±1.89 (25 years); the population was gradually reduced by winter wolf predation (Bergerud, 1989; 1996). The refuge habitat available is apparently insufficient for persistence in an area where the continuous distribution of woodland caribou is fragmented due to moose exceeding 0.10/km2 and thereby supporting wolf densities ≥6.5/1000 km2. A second experimental study was to introduce Slate Island caribou to areas with and without wolves. A release to Bowman Island, where wolves and moose were present, failed due to predation. Bowman Island is adjacent to St. Ignace Island where caribou had persisted into the late 1940s. A second release in 1989 to the mainland in Lake Superior Provincial Park of 39 animals has persisted (<10 animals) because the animals utilize off-shore islands but numbers are also declining. A third release to Montréal Island in 1984 doubled in numbers (up to 20 animals) until Lake Superior froze in 1994 and wolves reached the island. A fourth release was to Michipicoten Island (188 km2) in 1982 where wolves were absent and few lichens were available. This herd increased at λ= 1.18 (8 to ±200, 160 seen 2001) in 19 years. This was the island envisioned for the crucial test of the lichen/predation hypotheses (Bergerud, 1974: p.769). These studies strongly support the idea that ecosystems without predators are limited bottom–up by food and those with wolves top-down by predation; however the proposed crucial test which has been initiated on Michipicoten Island remains to be completed and there is a limited window of opportunity for unequivocal results.

Fascioloides magna (Trematoda) in woodland caribou (Rangifer tarandus caribou) of the George River herd, Labrador

1988 ◽  
Vol 66 (2) ◽  
pp. 475-479 ◽  
Author(s):  
Murray W. Lankester ◽  
Stu Luttich
Keyword(s):  
Rangifer Tarandus ◽  
Age Groups ◽  
Liver Weight ◽  
Rangifer Tarandus Caribou ◽  
Woodland Caribou ◽  
Intensity Of Infection ◽  
Fascioloides Magna ◽  
The Mean ◽  
George River ◽  
Liver Flukes

Fifty-eight percent of woodland caribou (Rangifer tarandus caribou) of the George River herd, Labrador, were infected with up to 110 giant American liver flukes (Fascioloides magna). The prevalence and intensity of infection did not differ between 2 sampling years or between sexes. Prevalence tended to increase with age while intensity did not differ among age groups. Liver weight increased with intensity of infection but condition, as measured by the mean depth of back fat, did not differ between infected and uninfected animals. Caribou must be considered a suitable host of F. magna since the growth and maturation of the parasite and lesions produced in Rangifer resemble those in deer and wapiti.

Variation in the seasonal selection of resources by woodland caribou in northern British Columbia

2008 ◽  
Vol 86 (8) ◽  
pp. 812-825 ◽  
Author(s):  
D. D. Gustine ◽  
K. L. Parker
Keyword(s):  
Conservation Planning ◽  
Resource Selection ◽  
Rangifer Tarandus ◽  
Rank Correlation ◽  
Late Winter ◽  
Theoretic Approach ◽  
Woodland Caribou ◽  
Predictive Capacity ◽  
Spearman’S Rank Correlation ◽  
Selection Strategies

Conservation planning for species of concern or importance can be aided by resource selection functions (RSFs) that identify important areas or attributes. Models that can be interpreted biologically and provide reasonable predictive capacity may best be based on data from individuals grouped into seasonal selection strategies for particular geographical areas or similarities in topographical and vegetative associations. We used logistic regression, the information–theoretic approach, satellite imagery, and locational data (n = 31 females; 16 803 locations) from global positioning system (GPS) collared woodland caribou ( Rangifer tarandus caribou (Gmelin, 1788)) to model resource selection by animals during calving, summer, fall, breeding, winter, and late-winter seasons. Higher variation in resource use corresponded to times when caribou and their young were most susceptible to predation or when food resources were limited. Even with multiple selection strategies, caribou followed a general progression from higher to lower elevation habitats from calving and summer to late winter. Caribou selected against or completely avoided the burned–disturbed vegetation class in every season except summer. We incorporated RSFs with a raster geographic information system to create selection landscapes. We validated selection landscapes using withheld GPS data (n = 6077), 50 known calving sites, and Spearman’s rank correlation coefficient. Selection models and final selection landscapes performed well in validating use locations of woodland caribou in all seasons (all P < 0.003) and in predicting known calving sites (P < 0.001). When seasonal selection strategies are identified and models are coupled with validation, RSFs are effective tools to assist in conservation planning.

scholarly journals Comparison of seasonal habitat selection between threatened woodland caribou ecotypes in central British Columbia

Rangifer ◽  
2007 ◽  
Vol 27 (4) ◽  
pp. 111 ◽  
Author(s):  
Elena S. Jones ◽  
Michael P. Gillingham ◽  
Dale R. Seip ◽  
Douglas C. Heard
Keyword(s):  
British Columbia ◽  
Habitat Use ◽  
Rocky Mountains ◽  
Vegetation Cover ◽  
Rangifer Tarandus ◽  
Late Winter ◽  
Woodland Caribou ◽  
Recovery Planning ◽  
Specific Mapping ◽  
Selection Of

Woodland caribou (Rangifer tarandus caribou) in British Columbia have been classified into ecotypes based on differences in use of habitat in winter. Although recovery planning focuses on ecotypes, habitat use and selection varies within ecotypes. Our objectives were to compare habitat use and selection among previously identified woodland caribou herds at the transition zone between northern (Moberly, Quintette, and Kennedy herds) and mountain (Parsnip herd) ecotypes in central British Columbia. We developed selection models for each herd in spring, calving, summer/fall, early and late winter. Topographic models best predicted selection by most herds in most seasons, but importance of vegetation-cover was highlighted by disproportionate use of specific vegetation-cover types by all caribou herds (e.g., in early winter, 75% of Kennedy locations were in pine-leading stands, 84% of Parsnip locations were in fir and fir-leading stands, and 87 and 96% of locations were in alpine for the Moberly and Quintette herds, respectively). Using a combination of GPS and VHF radio-collar locations, we documented some spatial overlap among herds within the year, but use of vegetation-cover types and selection of elevations, aspects, and vegetation-cover types differed among herds and within ecotypes in all seasons. Habitat use and selection were most similar between the two northern-ecotype herds residing on the eastern side of the Rocky Mountains. This research indicates that habitat use and selection by caribou herds in all seasons is more variable than ecotype classifications suggest and demonstrates the value of undertaking herd-specific mapping of critical habitat for woodland caribou.

scholarly journals Seasonal distribution and population parameters of woodland caribou in central Manitoba: implications for forestry practices

Rangifer ◽  
2000 ◽  
Vol 20 (5) ◽  
pp. 85 ◽  
Author(s):  
Kimberley G. Brown ◽  
Campbell Elliott ◽  
Francois Messier
Keyword(s):  
Boreal Forest ◽  
Rangifer Tarandus ◽  
Seasonal Distribution ◽  
Rate Of Change ◽  
Adult Survival ◽  
Rangifer Tarandus Caribou ◽  
Population Parameters ◽  
Woodland Caribou ◽  
Forestry Practices ◽  
Resource Exploration

Woodland caribou (Rangifer tarandus caribou) in the boreal forest are believed threatened by human encroachment and associated disturbances such as resource exploration and extraction. We radiocollared and monitored fifteen female woodland caribou in central Manitoba, from 1995 to 1997, to obtain information on their population range, seasonal distribution and movements in relation to forestry concerns. The population ranged over 4600 km2 within a large peatland system and concentrated their activities in two areas for both the summer and winter seasons. Females were relatively more solitary during the summer and exhibited fidelity to specific calving and summering areas averaging 83.4 km2. Individual wintering locations varied between years and among individuals. Post-rut and pre-calving mixed-sex aggregations occurred on the southern portion of the herds range. Caribou from the northern part of the range utilized a traditional travel corridor moving as far as 65 km to access the aggregation areas and their summer or winter ranges. Adult survival during the study period averaged 0.90 (95% CI, 0.80-1.00). Survival of the 1995 cohort appeared to be high as indicated by the 0.65:1 calf-cow ratio, and 30 &plusmn; 7% calf composition of observed caribou in the autumn of 1995. The annual rate of change (A,) of 1.19 (95% CI, 1.02-1.36) from January to November of 1995 indicated rhat the population was increasing at that time.

scholarly journals Population dynamics of the endangered mountain ecotype of woodland caribou (Rangifer tarandus caribou) in British Columbia, Canada

2020 ◽  
Author(s):  
Heiko Wittmer ◽  
BN McLellan ◽  
DR Seip ◽  
JA Young ◽  
TA Kinley ◽  
...  
Keyword(s):  
British Columbia ◽  
Population Dynamics ◽  
Rangifer Tarandus ◽  
Population Decline ◽  
Survival Rates ◽  
Adult Survival ◽  
Rangifer Tarandus Caribou ◽  
Vital Rates ◽  
Woodland Caribou ◽  
Annual Survival

We used census results and radiotelemetry locations of >380 collared individuals sampled over the entire distribution of the endangered mountain ecotype of woodland caribou (Rangifer tarandus caribou (Gmelin, 1788)) in British Columbia, Canada, to delineate population structure and document the size and trend of the identified populations. We also describe the spatial pattern of decline and the causes and timing of adult mortality and provide estimates of vital rates necessary to develop a population viability analysis. Our results indicate that the abundance of mountain caribou in British Columbia is declining. We found adult female annual survival rates below annual survival rates commonly reported for large ungulates. The major proximate cause of population decline appears to be predation on adult caribou. Spatial patterns of population dynamics revealed a continuous range contraction and an increasing fragmentation of mountain caribou into smaller, isolated subpopulations. The population fragmentation process predominantly occurs at the outer boundaries of the current distribution. Our results indicate that recovery strategies for mountain caribou should be directed at factors contributing to the fragmentation and isolation of mountain caribou populations as well as management strategies aimed at increasing adult survival. © 2005 NRC Canada.

Early-winter diet of woodland caribou in relation to snow accumulation, Selkirk Mountains, British Columbia, Canada

1990 ◽  
Vol 68 (12) ◽  
pp. 2691-2694 ◽  
Author(s):  
Eric M. Rominger ◽  
John L. Oldemeyer
Keyword(s):  
British Columbia ◽  
Rangifer Tarandus ◽  
Transition Period ◽  
Management Strategies ◽  
Snow Accumulation ◽  
Late Winter ◽  
Early Winter ◽  
Accumulation Rates ◽  
Woodland Caribou ◽  
Selkirk Mountains

Woodland caribou (Rangifer tarandus caribou) in the southern Selkirk Mountains of British Columbia shift from a diet of primarily vascular taxa during snow-free months to an arboreal lichen – conifer diet during late winter. We present evidence that caribou diets, during the early-winter transition period, are influenced by snow accumulation rates. Caribou shift to an arboreal lichen – conifer diet earlier during winters of rapid snow accumulation and forage extensively on myrtle boxwood (Pachistima myrsinites), an evergreen shrub, and other vascular plants during years of slower snow accumulation. The role of coniferous forage in early-winter food habits is examined. Forest management strategies can be developed to provide habitat that will enable caribou to forage in response to varying snow accumulation rates.

Widespread declines in woodland caribou (Rangifer tarandus caribou) continue in Alberta

2013 ◽  
Vol 91 (12) ◽  
pp. 872-882 ◽  
Author(s):  
D. Hervieux ◽  
M. Hebblewhite ◽  
N.J. DeCesare ◽  
M. Russell ◽  
K. Smith ◽  
...  
Keyword(s):  
Growth Rate ◽  
Adult Female ◽  
Industrial Development ◽  
Rangifer Tarandus ◽  
Population Trend ◽  
Late Winter ◽  
Rangifer Tarandus Caribou ◽  
Woodland Caribou ◽  
Structured Population Model ◽  
Female Survival

Nowhere across Canada is the continued persistence of woodland caribou (Rangifer tarandus caribou (Gmelin, 1788)) more uncertain than in Alberta due to widespread industrial development. A recent Government of Canada critical habitat review determined that habitat conditions within all Alberta boreal ecotype caribou ranges are unlikely or very unlikely to allow for self-sustaining caribou populations. This habitat-based assessment was based only indirectly on empirical population trends. Here, we estimated empirical population trend and growth rate (λ) for 13 of Alberta’s 16 remaining woodland caribou populations (plus one adjacent population from Saskatchewan) from 1994 to 2012 using demographic monitoring of adult female survival and calf recruitment. We captured and radio-collared a total of 1337 adult female caribou in 14 populations and estimated the mean annual adult female survival across all populations as 0.851. We conducted 158 late-winter calf recruitment surveys across the 14 populations classifying 20 872 caribou and estimated mean recruitment of 0.154 calves/cow (i.e., 0.077 female calves/cow). We then combined annual estimates of adult female survival and female calf recruitment within each population in a simple age-structured population model to estimate population trend. Annual population growth rate across caribou populations averaged 0.918, and was significantly declining, λ < 1.0, for 10 of the 14 caribou populations. Our results confirm that woodland caribou are declining rapidly (with a realized decline of approximately 50% every 8 years) across Alberta, and support conclusions from previous habitat-based assessments that the population viability of caribou is currently compromised, supporting development and implementation of recovery actions to reverse trends.

Competition potential between sympatric woodland caribou and wood bison in southwestern Yukon, Canada

2005 ◽  
Vol 83 (9) ◽  
pp. 1162-1173 ◽  
Author(s):  
Lisa A Fischer ◽  
C Cormack Gates
Keyword(s):  
Resource Selection ◽  
Rangifer Tarandus ◽  
Aerial Survey ◽  
Bison Bison ◽  
Late Winter ◽  
Lake Area ◽  
Woodland Caribou ◽  
Winter Diet ◽  
Wood Bison ◽  
Utilization Distributions

Wood bison (Bison bison athabascae Rhoads, 1898) were reintroduced to the Aishihik Lake area in the southwestern Yukon, where a population of woodland caribou (Rangifer tarandus caribou (Gmelin, 1788)) existed. These species co-occurred in nearby Beringia over several hundred thousand years and in the study area throughout most of the Holocene. We hypothesized that resource-selection patterns should differ widely between species at all scales because co-evolution should have resulted in strong patterns of resource partitioning. We compared winter utilization distributions of both species based on aerial survey data and assessed differential resource selection at the scales of landscape and distributional overlap. We also assessed differential resource use within feeding sites and compared late-winter diets of the two species. We found 41% overlap in 95% utilization distributions but only 6% overlap in 50% utilization distributions. Strong differences were measured for use of space and terrain, including elevation, slope, and distance from permanent water bodies. Bison strongly selected for or used graminoids, while caribou selected for or used lichens at each scale. Overlap in winter diet between the two species was 10%. At current densities, exploitative competition in winter between these species is unlikely.

scholarly journals Population ecology of two woodland caribou herds in the southern Yukon

Rangifer ◽  
1996 ◽  
Vol 16 (4) ◽  
pp. 63 ◽  
Author(s):  
Richard Farnell ◽  
Norman Barichello ◽  
Katherina Egli ◽  
Gerry Kuzyk
Keyword(s):  
Population Ecology ◽  
Rangifer Tarandus ◽  
Distribution Patterns ◽  
Late Winter ◽  
Woodland Caribou ◽  
Winter Range ◽  
Pup Survival ◽  
Moose Population ◽  
Snow Conditions ◽  
The Impact

Since the mid 1980's, the Aishihik herd of woodland caribou (Rangifer tarandus caribou) declined from approximately 1500 to 583 animals. During the same period a nearby herd, the Wolf Lake Herd increased from approximately 664 to 1249 animals. This paper compares aspects of the ecology of these two herds to determine how these relationships conform to a general model of caribou population ecology described by Seip (1992). Comparisons include caribou demographic characteristics and distribution patterns, predator densities, abundance of alternate prey, human hunting and snow depth on caribou winter range. Ecological differences between herds were apparent in the ratio of prime bulls to cows, the abundance of moose (Alces alces), the occurrence of coyotes (Canis latrans), late winter snow conditions, and access to hunting. We hypothesize that the Wolf Lake herd was able to grow because wolves {Canis lupus) preyed mainly on the relatively abundant moose population. A highly clumped winter caribou distribution may have further reduced the impact of wolf predation on the Wolf Lake herd. In contrast, the decline of the Aishihik herd was accompanied by a relative scarcity of moose, few prime aged caribou bulls probably due to a more liberal trophy harvest, and wider late-winter dispersion that offered wolves greater access to caribou. The decline may have been exaggerated by the peak in the snowshoe hare (Lepus americanus) cycle which may have temporarily improved wolf pup survival. We suspect that moose are normally the primary prey of wolves in the Yukon and that a decline in moose eventually results in their being too scarce to offer an economical prey choice, prompting a prey switch to caribou. Results of our analyses conform incompletely to Seip's (1992) model for woodland caribou population ecology, particularly because the Wolf Lake herd prospered where moose were relatively abundant.

scholarly journals Status of woodland caribou in western north America

Rangifer ◽  
1991 ◽  
Vol 11 (4) ◽  
pp. 91 ◽  
Author(s):  
E. Janet Edmonds
Keyword(s):  
Land Use ◽  
North America ◽  
Rangifer Tarandus ◽  
Relative Distribution ◽  
Western North America ◽  
Woodland Caribou ◽  
Habitat Changes ◽  
Wide Range ◽  
Unknown Status ◽  
Management Approaches

A review of current population size and trends of woodland caribou (Rangifer tarandus caribou) in seven jurisdictions in western North America shows a wide range of situations. A total maximum population estimate of woodland caribou west of the Ontario/Manitoba border is 61 090. Of 44 herds or populations described in this review: 14 are stable; two are stable to slightly decreasing; four are decreasing; four are increasing; and 22 are of unknown status. Caribou are classified as a threatened species in Alberta and as an endangered species in Washington/Idaho. The decline of caribou in North America following settlement (Bergerud, 1974) has continued along the southern edge of woodland caribou distribution. Direct loss of habitat to logging, mines and dams continued throughout the I960s, 1970s and 1980s. The secondary effects of these habitat changes, (i.e. increased roads leading to increased hunting and poaching, and increased early succession habitat leading to increased alternate prey/predator densities) has led in some cases to the total loss or decreased size of local herds. Three ecotypes of woodland caribou are described and their relative distribution delineated. These ecotypes live under different environmental conditions and require different inventory and management approaches. Woodland caribou herds in northern B.C., Yukon and N.W.T. generally are of good numbers and viable (stable or increasing), and management primarily is directed at regulating human harvest and natural predation to prevent, herd declines. Land use activities such as logging or energy development are not extensive. Managers in southern caribou ranges stress the need for a better understanding of caribou population stability within mixed prey/predator regimes; how habitat changes (eg. through logging) affect these regimes; and how to develop effective land use guidelines for resource extraction that can sustian caribou populations and maintain resource industries. Caribou managers have suggested that herds may be priorized for research and management efforts. Unstable, remnant populations may be left to their own fate. The limited research dollars available and difficult management decisions should be applied to caribou herds that are apparently sustainable and provide the greatest potential for long-term viability.

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