Diets of Overwintering Caribou, &lt;em&gt;Rangifer tarandus&lt;/em&gt;, Track Decadal Changes in Arctic Tundra Vegetation

Joly, Kyle; Cole, M. Jeanie; Jandt, Randi R.

doi:10.22621/cfn.v121i4.509

Cited by 33 publications

(32 citation statements)

References 37 publications

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“…These habitat types typically have relatively high lichen cover (Swanson et al, 1985). Lichens are an important component of the winter diet of WAH caribou, making up a majority of their forage (Saperstein, 1996;Joly et al, 2007b). Concurrent with major declines in lichen cover within the core winter range of the WAH (Joly et al, 2007c) and the percentage of lichens in their winter diet (Joly et al, 2007b), the size of the WAH peaked and has declined for the first time in 30 years.…”

Section: Discussionmentioning

confidence: 99%

“…Lichens are an important component of the winter diet of WAH caribou, making up a majority of their forage (Saperstein, 1996;Joly et al, 2007b). Concurrent with major declines in lichen cover within the core winter range of the WAH (Joly et al, 2007c) and the percentage of lichens in their winter diet (Joly et al, 2007b), the size of the WAH peaked and has declined for the first time in 30 years. Though only anecdotal, this evidence supports the theory (Klein, 1991) that lichens may be a critical component of the winter diet of large migratory herds in North America (see also Holleman et al, 1979).…”

Section: Discussionmentioning

confidence: 99%

“…Snow characteristics are impor¬ tant because movement can be impeded by deep snow, while foraging efficiency can be reduced by either deep or crusted snow (Skogland, 1978;Fancy & White, 1985;Fancy & White, 1987;Collins & Smith, 1991;Joly et al, 2011). Habitat is an impor¬ tant factor because lichens comprise the majority of the winter diet of WAH cari¬ bou (Saperstein, 1996;Joly et al, 2007b). Pregnant caribou should be the most reliant on high quality habitat dur¬ ing the winter months as their energetic demands are relatively higher than other classes of caribou (Cam¬ eron et al,, 1993;Barboza & Parker, 2008).…”

Section: Introductionmentioning

confidence: 99%

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Modeling influences on winter distribution of caribou in northwestern Alaska through use of satellite telemetry

Joly

2011

Ran

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I hypothesize that the distribution of barren-ground caribou (Rangifer tarandus granti) is affected by multiple, interrelated factors. These factors include, but are not limited to, terrain and snow characteristics as well as predation pressure and habitat. To test this hypothesis, I attributed caribou locations derived from satellite telemetry over a 6 year period with terrain (elevation, slope, aspect, and ruggedness), habitat characteristics, and moose density -potentially an index of wolf predation pressure. These locations were compared to random locations, attributed using the same data layers, using logistic regression techniques to develop resource selection functions (RSFs). I found that caribou moved significantly less during mid-winter than early-or late-winter and that cows moved significantly more in April than bulls due to their earlier departure on their spring migration. Distribution was different between cows and bulls. Terrain variables were important factors but were scale-dependent. Cows avoided forested areas, highlighting the importance of tundra habitats, and selected for dwarf shrub, with relatively high lichen cover, and sedge habitat types. Bulls selected for dryas, coniferous forest and dwarf shrub habitats but against lowland sedge, upland shrub and burned tundra. Cow distribution was negatively correlated with moose density at the scale of the Seward Peninsula. My results support the hypothesis that caribou distribution during winter in northwest Alaska is affected by multiple, interrelated factors. These results may be useful for researchers to track and/or model changes in future patterns of range use over winter.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Modeling influences on winter distribution of caribou in northwestern Alaska through use of satellite telemetry

Joly

2011

Ran

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“…Such estimates remain elusive; however, our spatial models of bryophyte cover provide a starting point for efforts to predict moss thickness, particularly in areas with high total cover. Lichen cover estimates are highly desirable for efforts to monitor winter forage for Arctic caribou herds [34].…”

Section: Correspondence Of Pfts and Environmental Gradientsmentioning

confidence: 99%

Regional Quantitative Cover Mapping of Tundra Plant Functional Types in Arctic Alaska

et al. 2017

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Ecosystem maps are foundational tools that support multi-disciplinary study design and applications including wildlife habitat assessment, monitoring and Earth-system modeling. Here, we present continuous-field cover maps for tundra plant functional types (PFTs) across~125,000 km 2 of Alaska's North Slope at 30-m resolution. To develop maps, we collected a field-based training dataset using a point-intercept sampling method at 225 plots spanning bioclimatic and geomorphic gradients. We stratified vegetation by nine PFTs (e.g., low deciduous shrub, dwarf evergreen shrub, sedge, lichen) and summarized measurements of the PFTs, open water, bare ground and litter using the cover metrics total cover (areal cover including the understory) and top cover (uppermost canopy or ground cover). We then developed 73 spectral predictors derived from Landsat satellite observations (surface reflectance composites for~15-day periods from May-August) and five gridded environmental predictors (e.g., summer temperature, climatological snow-free date) to model cover of PFTs using the random forest data-mining algorithm. Model performance tended to be best for canopy-forming PFTs, particularly deciduous shrubs. Our assessment of predictor importance indicated that models for low-statured PFTs were improved through the use of seasonal composites from early and late in the growing season, particularly when similar PFTs were aggregated together (e.g., total deciduous shrub, herbaceous). Continuous-field maps have many advantages over traditional thematic maps, and the methods described here are well-suited to support periodic map updates in tandem with future field and Landsat observations.

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“…Overwintering caribou that incur the energetic expenses of migration and predation, such as the WAH, utilize lichens as their major food source (Klein 1982, Russell et al 1993, Joly et al 2007b). They are a critical source of carbohydrates that help these caribou survive winter until emergent forage appears in the spring (Person et al 1980, Parker et al 2005.…”

Section: Discussionmentioning

confidence: 99%

Simulating the effects of climate change on fire regimes in Arctic biomes: implications for caribou and moose habitat

Joly

Duffy²,

Rupp

2012

Ecosphere

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Citation: Joly, K., P. A. Duffy, and T. S. Rupp. 2012. Simulating the effects of climate change on fire regimes in Arctic biomes: implications for caribou and moose habitat. Ecosphere 3(5):36. http://dx.doi.org/10.1890/ES12-00012.1Abstract. Wildfire is the primary ecological driver of succession in the boreal forest and may become increasingly important within tundra ecosystems as the Arctic warms. Migratory barren-ground caribou (Rangifer tarandus granti ) rely heavily on terricolous lichens to sustain them through the winter months. Lichens preferred by caribou can take 50 or more years to recover after being consumed by wildfires. We simulated effects of climate change on the fire regime within the winter range of one of the largest caribou herds in the world, the Western Arctic Herd, to assess how their forage may be impacted. We forecast that the total area burned (AB) in the near term (2008-2053) will be 0-30% greater than during our historic reference period depending on the climate model (CGCM3.1 or ECHAM5) considered. Further into the future (i.e., 2054-2099), we forecast AB to increase 25-53% more than during our reference period. In contrast to the entire study area, which contains both tundra and boreal forest habitats, we forecast that the amount of AB in tundra alone will increase (0-61%) in the near term. Simulated highquality caribou winter range, as indexed by tundra and spruce habitat that had not burned in 50 years, decreased modestly (,6%) in the near term over the entire study area. Simulated changes were more dramatic within the herd's core winter range, with declines in high-quality caribou winter range approaching 30%. Conversely, moose habitat was projected to increase by 19-64% within the core winter range in the near term. The simulated declines in the quantity of core winter range in the future due to larger and more frequent fires could impact caribou abundance through decreased nutritional performance and/or apparent competition with moose. These impacts would likely be detrimental to the subsistence users that rely on this resource. Additionally, changes in the fire regime and decreases in caribou abundance could amplify feedback mechanisms, such as decreasing albedo, by facilitating shrub growth that may hasten climate-driven changes to the composition and structure of vegetation communities in the low Arctic.

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Diets of Overwintering Caribou, <em>Rangifer tarandus</em>, Track Decadal Changes in Arctic Tundra Vegetation

Cited by 33 publications

References 37 publications

Modeling influences on winter distribution of caribou in northwestern Alaska through use of satellite telemetry

Modeling influences on winter distribution of caribou in northwestern Alaska through use of satellite telemetry

Regional Quantitative Cover Mapping of Tundra Plant Functional Types in Arctic Alaska

Simulating the effects of climate change on fire regimes in Arctic biomes: implications for caribou and moose habitat

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