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Data from: Population size and major valleys explain microsatellite variation better than taxonomic units for caribou in western Canada
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Serrouya, Robert; Paetkau, David; McLellan, Bruce N.; Boutin, Stan; Jenkins, Deborah A.; Campbell, Mitch — 2012-03-02 Identifying conservation units below the species level is becoming increasingly important, particularly when limited resources necessitate prioritization for conservation among such units. This problem is exemplified with caribou, a mammal with a circum-Arctic distribution that is exposed to a broad spectrum of ecological conditions, but is also declining in many parts of its range. We used microsatellite markers to evaluate the suitability of existing intra-specific taxonomic designations to act as population units for conservation, and contrasted this with landscape features that were independent of taxonomy. We also quantified the relationship between genetic differentiation and subpopulation size, a factor that has been under-represented in landscape genetic research. Our dataset included three subspecies and three ecotypes of caribou that varied in population size by five orders of magnitude. Our results indicated that genetic structure did not correspond to existing taxonomic designation, particularly at the level of ecotype. Instead, we found that major valleys and population size were the strongest factors associated with substructure. There was a negative exponential relationship between population size and FST between pairs of adjacent subpopulations, suggesting that genetic drift was the mechanism causing the structure among the smallest subpopulations. A genetic assignment test revealed that movement among subpopulations was a fraction of the level needed to stabilize smaller subpopulations, indicating little chance for demographic rescue. Such results may be broadly applicable to landscape genetic studies, because population size and corresponding rates of drift have the potential to confound interpretations of landscape effects on population structure.
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Woodland Caribou demographic data and range boundaries
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DeMars, Craig; Boutin, Stan; Serrouya, Robert; Gilbert, Sophie; Kelly, Allicia; Larter, Nicholas; Hervieux, Dave — 2021-10-07 <p>As global climate change progresses, wildlife management will benefit from knowledge of demographic responses to climatic variation, particularly for species already endangered by other stressors. In Canada, climate change is expected to increasingly impact populations of threatened woodland caribou (<i>Rangifer tarandus caribou</i>) and much focus has been placed on how a warming climate has potentially facilitated the northward expansion of apparent competitors and novel predators. Climate change, however, may also exert more direct effects on caribou populations that are not mediated by predation. These effects include meteorological changes that influence resource availability and energy expenditure. Research on other ungulates suggests that climatic variation may have minimal impact on low-density populations such as woodland caribou because per-capita resources may remain sufficient even in “bad” years. We evaluated this prediction using demographic data from 21 populations in western Canada that were monitored for various intervals between 1994 and 2015. We specifically assessed whether juvenile recruitment and adult female survival were correlated with annual variation in meteorological metrics and plant phenology. Against expectations, we found that both vital rates appeared to be influenced by annual climatic variation. Juvenile recruitment was primarily correlated with variation in phenological conditions in the year prior to birth. Adult female survival was more strongly correlated with meteorological conditions and declined during colder, more variable winters. These responses may be influenced by the life history of woodland caribou, which reside in low-productivity refugia where small climatic changes may result in changes to resources that are sufficient to elicit strong demographic effects. Across all models, explained variation in vital rates was low, suggesting that other factors had greater influence on caribou demography. Nonetheless, given the declining trajectories of many woodland caribou populations, our results highlight the increased relevance of recovery actions when adverse climatic conditions are likely to negatively affect caribou demography.</p>
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Data associated with: Applying remote sensing for large-landscape problems: Inventorying and tracking habitat recovery for a broadly distributed Species At Risk
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Dickie, Melanie; Hricko, Branislav; Hopkinson, Christopher; Tran, Victor; Kohler, Monica; Toni, Sydney; Serrouya, Robert; Kariyeva, Jahan — 2023-06-19 <ol start="1" type="1"> <li> <p><span lang="EN">Anthropogenic habitat alteration is leading to the reduction of global biodiversity. Consequently, there is an imminent need to understand the state and trend of habitat alteration across broad areas. In North America, habitat alteration has been linked to the decline of threatened woodland caribou. As such, habitat protection and restoration are critical measures to support recovery of self-sustaining caribou populations. Broad estimates of habitat change through time have set the stage for understanding the status of caribou habitat. However, the lack of updated and detailed data on post-disturbance vegetation recovery is an impediment to recovery planning and monitoring restoration effectiveness. Advances in remote sensing tools to collect high-resolution data at large spatial scales are beginning to enable ecological studies in new ways to support ecosystem-based and species-based management.</span></p> </li> <li> <p><span lang="EN">We used semi-automated and manual methodologies to fuse photogrammetry point clouds (PPC) from high-resolution aerial imagery with wide-area Light Detection and Ranging (LiDAR) data to quantify vegetation structure (height, density, class) on disturbances associated with caribou declines. We also compared vegetation heights estimated from the semi-automated PPC-LiDAR fusion to heights estimated in the field, using stereoscopic interpretation, and using multi-channel TiTAN LiDAR.</span></p> </li> <li> <p><span lang="EN">Vegetation regrowth was occurring on many of the disturbance types, though there was local variability in the type, height, and density of vegetation. Heights estimated using PPC-LiDAR fusion were highly correlated (r ≥ 0.87 in all cases) with heights estimated using stereomodels, TiTAN multi-channel LiDAR, and field measurements. </span></p> </li> <li> <p>We demonstrated that PPC-LiDAR fusion can be operationalized over large areas to collect comprehensive and consistent vegetation data across landscape levels, providing opportunities to link fine-resolution remote sensing to landscape-scale ecological studies. Crucially, these data can be used to estimate rates of habitat recovery at resolutions that are not feasible using more commonly used satellite-based sensors, bridging the gap between resolution and extent.  Such data are needed to achieve effective and efficient habitat monitoring to support caribou recovery efforts, as well as a myriad of additional forest management needs.</p> </li> </ol>
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Data from: Faster and farther: wolf movement on linear features and implications for hunting behaviour
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Dickie, Melanie; Serrouya, Robert; McNay, R. Scott; Boutin, Stan — 2017-06-21 Predation by grey wolves Canis lupus has been identified as an important cause of boreal woodland caribou Rangifer tarandus caribou mortality, and it has been hypothesized that wolf use of human-created linear features such as seismic lines, pipelines and roads increases movement, resulting in higher kill rates. We tested if wolves select linear features and whether movement rates increased while travelling on linear features in north-eastern Alberta and north-western Saskatchewan using 5-min GPS (Global Positioning System) locations from twenty-two wolves in six packs. Wolves selected all but two linear feature classes, with the magnitude of selection depending on feature class and season. Wolves travelled two to three times faster on linear features compared to the natural forest. Increased average daily travelling speed while on linear features and increased proportion of steps spent travelling on linear features increased net daily movement rates, suggesting that wolf use of linear features can increase their search rate. Synthesis and applications. Our findings that wolves move faster and farther on human-created linear features can inform mitigation strategies intended to decrease predation on woodland caribou, a threatened species. Of the features that can realistically be restored, mitigation strategies such as silviculture and linear deactivation (i.e. tree-felling and fencing) should prioritize conventional seismic lines (i.e. cleared lines used for traditional oil and gas exploration) and pipelines, as they were selected by wolves and increased travelling speed, before low-impact seismic lines.

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(Author: Serrouya, Robert)

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