Columbia Mountains Caribou Project

Nelson, Canada

Columbia Mountains Caribou Project

Nelson, Canada
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Serrouya R.,University of Alberta | Kellner A.,Columbia Mountains Caribou Project | Pavan G.,Columbia Mountains Caribou Project | Lewis D.W.,Columbia Mountains Caribou Project | And 4 more authors.
Ecosphere | Year: 2017

Quantifying resource use or selection by valued species on a human-Altered landscape is important for wise conservation action. Here, we contrast metrics of resource selection based on Global Positioning System (GPS) telemetry, which indexes time spent in various habitats, with tracking in snow, which measures distance travelled. When animals move at different speeds within different habitats, the two methods can produce different results. The study was conducted in winter on endangered mountain caribou (Rangifer tarandus caribou) in a landscape fragmented by forestry roads and cutblocks. From 2001 to 2009, 25 caribou were monitored with GPS collars obtaining locations every two to six hours, and compared to 63 caribou trails followed in snow in the same study area and time period. Logistic regression was used to estimate selection for both metrics, with the same definition of use and availability employed. Forest age, tree species, edge distances, and road densities were the covariates of interest. For most covariates, the two metrics produced similar results that agreed with the literature: selection for primary forest stands that represent forage patches. Both metrics indicated selection for habitat edges that potentially enhance foraging. The distance metric (snow trailing) indicated strong selection for forestry roads (42% more than available), whereas GPS locations suggested an avoidance of roads (33% less than available). The GPS analysis was in agreement with the vast majority of work published on woodland caribou, whereas the distance metric suggests some of the first evidence of selection for anthropogenic linear features. Our results highlight a potential bias against detecting selection for habitat features used for movement when using long fix intervals (>2 h) that typify most GPS studies. Avoidance of linear features should be carefully examined and designs considered to asses this bias. Finally, the selection of roads by caribou exacerbates an already desperate situation by creating a potential trap because roads are also preferred by some predators. © 2017 Serrouya et al.


Apps C.D.,Aspen Wildlife Research | McLellan B.N.,British Columbia Ministry of forests | Kinley T.A.,Sylvan Consulting | Serrouya R.,Columbia Mountains Caribou Project | And 2 more authors.
Journal of Wildlife Management | Year: 2013

Mountain caribou are an endangered ecotype of woodland caribou (Rangifer tarandus caribou) that historically occurred throughout the high snowfall regions of southeast British Columbia and the northwestern United States. The decline in caribou is thought to be due to apparent competition where increases in early-seral conditions stimulate a numerical response in primary ungulate prey and their predators and these incidentally kill an unsustainable number of caribou. Based on the known location of death of 207 radio collared animals, we tested hypotheses pertaining to relationships between landscape composition and predator-specific mortality of mountain caribou at 2 ecologically based spatial scales. Relative to landscape conditions within subpopulation boundaries (level 1) or within home ranges (level 2), caribou were at greater risk of predation at low elevations particularly within otherwise complex terrain (i.e., valleys) with more variation in overstory canopy closure and greater road densities. Caribou vulnerability to bears was also positively related to the variation in overstory age. Cougar predation was not related to roads or terrain complexity but occurred more often in landscapes with warmer aspects and greater proportions of stands of <120 years. Wolf predation occurred primarily at low elevations at the broader scale and in association with roads at the finer scale. Our results indicate that caribou vulnerability to predation was a function of both static (e.g., terrain) and dynamic (e.g., overstory conditions) factors, but we did not find evidence that localized habitat fragmentation due to forest harvest influenced predation on caribou. This result is not inconsistent with the apparent competition hypothesis but suggests that habitat change largely functions at broader spatial scales involving landscapes that can be beyond those occupied by caribou, including the winter ranges of primary ungulate prey. These changes and the season-dependent dispersion of other ungulates and their predators may largely influence mortality risk to mountain caribou. Although roads and forest fragmentation are interrelated, roads may further contribute to caribou predation by increasing the efficiency of movement of some predators and thereby increasing encounter rates with caribou. © 2013 The Wildlife Society. Copyright © The Wildlife Society, 2013.


Serrouya R.,University of Alberta | McLellan B.N.,British Columbia Ministry of forests | Pavan G.D.,Columbia Mountains Caribou Project | Apps C.D.,Aspen Wildlife Research
Journal of Wildlife Management | Year: 2011

In mountainous areas with sufficient snowfall, avalanche chutes are an important component of grizzly bear (Ursus arctos) habitat. Therefore, regional land-use plans have recommended retaining adjacent forest buffers to maintain security and thus reduce potential impacts of clearcut forest harvesting. Our objective was to determine if forest buffers affected selection of avalanche chutes by grizzly bears, while accounting for factors such as vegetation composition and other physical attributes. We used radio-location data from 61 grizzly bears collected between 1994 and 2000 in southern British Columbia, mapped a sample of avalanche chutes (1,045), and quantified the amount of forb, shrub, tree, and non-vegetated cover within each chute. We also measured forested buffer width on each side of the chute, solar radiation, chute size, chute frequency (no. of chutes/km), and the area of clearcut logging adjacent to chutes. Each avalanche chute was the sample unit and the number of grizzly bear radiolocations was the dependent variable. We found that natural biophysical attributes were the strongest factors predicting the level of avalanche chute use by bears. Frequency of large chutes (>100 m wide), chute area, forb content, and solar radiation all positively affected use by bears. Larger avalanche chutes had a higher proportion of forb cover than smaller chutes, and more of these large chutes per unit area provided increased forage opportunities. Based on multivariate analyses, forested buffer width or the amount of clearcut logging were not strong factors predicting the level of use. However, a post hoc univariate analysis revealed that clearcut logging reduced the amount of bear use of the best avalanche chutes (large and abundant chutes). Furthermore, because a portion of our study area contained logging but no vehicle traffic, we concluded that it was the removal of tree cover, rather than displacement by vehicles, that caused the observed pattern. Although our multivariate models did not perform well using independent validation in a different geographic area, 4 factors were consistently important (large and abundant chutes, forb content, with a negative but weaker influence of clearcutting), suggesting broad applicability of these factors in mountainous ecosystems. © 2011 The Wildlife Society.


van Oort H.,Columbia Mountains Caribou Project | Mclellan B.N.,British Columbia Ministry of forests | Serrouya R.,Columbia Mountains Caribou Project | Serrouya R.,University of Alberta
Animal Conservation | Year: 2011

Populations that are fragmented in space may persist because of metapopulation function that relies on dispersal among subpopulations. Assuming that a fragmented distribution means that the species operates as a metapopulation can lead to erroneous conclusions about population structure, unless the dispersal traits of the organism are understood. A wide-ranging large mammal with an increasingly fragmented distribution is the mountain caribou, found in the interior rain forests of British Columbia, Canada. These caribou are an endangered ecotype of woodland caribou Rangifer tarandus caribou, and, based on movements of adult caribou, their population has been divided into 18 subpopulations. Their numbers have declined over at least the last 25years, and it is unknown if their fragmented distribution operates as a metapopulation linked by juvenile dispersal or is simply a step towards extinction. From a database of radio-locations collected over a 23-year period (1984-2007) from 358 caribou, we used a spatial index to define summer/fall composite ranges (breeding ranges) across their distribution. The 18 previously recognized subpopulations were fragmented further into 41 summer/fall composite ranges. Young animals (<1year of age) were not observed to disperse among subpopulations (0/26 opportunities) or even among summer/fall composite ranges (0/7). Similar results were found for animals 2 and 3years of age. Breeding dispersal by adult caribou occurred in 1.4% of the observed opportunities (8/587). These dispersal rates are insufficient to rescue the smaller and declining subpopulations. We conclude that the distribution of these mountain caribou is more fragmented than thought previously and is not functioning as a classic metapopulation due to a lack of dispersal; rather, it is better described as an extreme non-equilibrium metapopulation. Mountain caribou and other wide-ranging species fragmented into subpopulations by human actions may appear to be in a metapopulation but unless they have the innate ability to disperse among subpopulations, the distribution is more likely the geographic pattern of the extinction process. © 2010 The Authors. Animal Conservation © 2010 The Zoological Society of London.


McLellan M.L.,Columbia Mountains Caribou Project | Serrouya R.,University of Alberta | McLellan B.N.,British Columbia Ministry of Natural Resource Operations | Furk K.,Columbia Mountains Caribou Project | And 2 more authors.
Oecologia | Year: 2012

Both top-down and bottom-up processes influence herbivore populations, and identifying dominant limiting factors is essential for applying effective conservation actions. Mountain caribou are an endangered ecotype of woodland caribou (Rangifer tarandus caribou) that have been declining, and unsustainable predation has been identified as the proximate cause. To investigate the role of poor nutrition, we examined the influence of sex, season, age class, and available suitable habitat (i. e., old-growth forest >140 years) per caribou on bone marrow fat content of caribou that died (n = 79). Sex was the only strong predictor of marrow fat. Males that died during and post rut had lower marrow fat than females or males at other times of year. Old-growth abundance per caribou, season, and age class did not predict marrow fat. Caribou killed by predators did not have less marrow fat than those that died in accidents, suggesting that nutritionally stressed caribou were not foraging in less secure habitats or that predators selected nutritionally stressed individuals. Marrow fat in endangered and declining populations of mountain caribou was similar to caribou in other, more viable populations. Our results support previous research suggesting that observed population declines of mountain caribou are due to excessive predation that is not linked to body condition. © 2011 Springer-Verlag.


PubMed | Columbia Mountains Caribou Project
Type: Journal Article | Journal: Oecologia | Year: 2012

Both top-down and bottom-up processes influence herbivore populations, and identifying dominant limiting factors is essential for applying effective conservation actions. Mountain caribou are an endangered ecotype of woodland caribou (Rangifer tarandus caribou) that have been declining, and unsustainable predation has been identified as the proximate cause. To investigate the role of poor nutrition, we examined the influence of sex, season, age class, and available suitable habitat (i.e., old-growth forest>140 years) per caribou on bone marrow fat content of caribou that died (n = 79). Sex was the only strong predictor of marrow fat. Males that died during and post rut had lower marrow fat than females or males at other times of year. Old-growth abundance per caribou, season, and age class did not predict marrow fat. Caribou killed by predators did not have less marrow fat than those that died in accidents, suggesting that nutritionally stressed caribou were not foraging in less secure habitats or that predators selected nutritionally stressed individuals. Marrow fat in endangered and declining populations of mountain caribou was similar to caribou in other, more viable populations. Our results support previous research suggesting that observed population declines of mountain caribou are due to excessive predation that is not linked to body condition.

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