Boreal caribou survival in a warming climate, Labrador, Canada 1996–2014

Schmelzer, Isabelle; Lewis, Keith P.; Jacobs, John D.; McCarthy, Sara C.

doi:10.1016/j.gecco.2020.e01038

Cited by 15 publications

(16 citation statements)

References 94 publications

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“…Climatic effects on AFS of woodland caribou were somewhat surprising, given the expectation that low-density populations should show weaker responses to climatic variation [2,5] and that among vital rates, AFS should be the least sensitive [66]. Previous research on woodland caribou in eastern Canada found weak climatic effects on AFS (weak positive correlation with increasing snowfall; [29]). Our differing results underscore how demographic effects from climatic variation are likely to be context-specific.…”

Section: Adult Female Survivalmentioning

confidence: 99%

“…Generalizing across species is particularly problematic as differences in life-history traits can cause species to vary in their response to similar climatic effects. For example, Wilmers et al [7] reported that increasing snow depth interacted with predation to lower survival in elk (Cervus elaphus) whereas increasing snow depth had a weak positive effect on adult female survival in the boreal ecotype of woodland caribou (Rangifer tarandus caribou; [29]). Responses to climatic variation may also be variable within species as typified by contrasting climate-demographic relationships reported for caribou and reindeer.…”

Section: Introductionmentioning

confidence: 99%

“…To date, few studies have investigated direct climate-related effects on the demography of woodland caribou and all have been restricted to a few discrete areas within the broad and varied geographic distribution of these caribou (e.g., [6,29,30,40]); consequently, the demographic responses of most woodland populations to climatic variation remains largely unknown. This knowledge gap is perhaps surprising for an iconic, threatened animal, but one potential reason for the lack of research in this area is that prevailing literature predicts weak or muted demographic responses of woodland caribou to climatic variation.…”

Section: Introductionmentioning

confidence: 99%

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Demographic responses of a threatened, low-density ungulate to annual variation in meteorological and phenological conditions

et al. 2021

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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 (Rangifer tarandus caribou) 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.

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Section: Adult Female Survivalmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Demographic responses of a threatened, low-density ungulate to annual variation in meteorological and phenological conditions

et al. 2021

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“…The examples involving Caribou declines that Tom witnessed and acknowledged include complexities not only in bear and lynx as additional predators in Newfoundland (Lewis et al 2017), but also in variable effects of predation in Newfoundland that depend on weather (Bastille-Rousseau et al 2015), on Caribou population dynamics (Mahoney et al 2016), and on changes to their behaviour with food limitation (Schaefer et al 2016). Variable Caribou population dynamics also occur with changing snow and freezing rain conditions in Labrador (Schmeltzer et al 2020) and, as shown for the mountain populations in Alberta and BC, with human disturbance that can shift both Caribou behaviour (MacNearney et al 2016) and Gray Wolf hunting efficiency (Pigeon et al 2020). Caribou are also often not given enough space, and the space they are given as "critical habitat" continues to be fragmented; Palm et al (2020) recently reiterated this point for the BC populations that were so often top of Tom's mind: fragmentation reduces or eliminates the value of the shrinking space for Caribou as a refuge from predation.…”

Section: Discussionmentioning

confidence: 99%

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Lepitzki¹

2021

Can Field Nat

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The objectives of this Club shall be to promote the appreciation, preservation, and conservation of Canada's natural heritage; to encourage investigation and publish the results of research in all fields of natural history and to diffuse information on these fields as widely as possible; to support and cooperate with organizations engaged in preserving, maintaining, or restoring environments of high quality for living things.

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“…Recent studies have indicated that the mapping of caribou lichen is vital for sustainable land management and caribou recovery plans [1][2][3][4][5]. Canadian caribou are threatened by a changing environment due to declining lichen availability, unregulated hunting, habitat disturbances, and herd fragmentation due to human-made infrastructure [2][3][4][5][6]. Lichen is a dominant food source for caribou in the winter, comprising 75% and 25% of their diets in the winter and summer seasons respectively [5].…”

Section: Introductionmentioning

confidence: 99%

Leveraging AI to Estimate Caribou Lichen in UAV Orthomosaics from Ground Photo Datasets

Richardson

Leblanc

Lovitt

et al. 2021

Drones

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Relating ground photographs to UAV orthomosaics is a key linkage required for accurate multi-scaled lichen mapping. Conventional methods of multi-scaled lichen mapping, such as random forest models and convolutional neural networks, heavily rely on pixel DN values for classification. However, the limited spectral range of ground photos requires additional characteristics to differentiate lichen from spectrally similar objects, such as bright logs. By applying a neural network to tiles of a UAV orthomosaics, additional characteristics, such as surface texture and spatial patterns, can be used for inferences. Our methodology used a neural network (UAV LiCNN) trained on ground photo mosaics to predict lichen in UAV orthomosaic tiles. The UAV LiCNN achieved mean user and producer accuracies of 85.84% and 92.93%, respectively, in the high lichen class across eight different orthomosaics. We compared the known lichen percentages found in 77 vegetation microplots with the predicted lichen percentage calculated from the UAV LiCNN, resulting in a R2 relationship of 0.6910. This research shows that AI models trained on ground photographs effectively classify lichen in UAV orthomosaics. Limiting factors include the misclassification of spectrally similar objects to lichen in the RGB bands and dark shadows cast by vegetation.

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Boreal caribou survival in a warming climate, Labrador, Canada 1996–2014

Cited by 15 publications

References 94 publications

Demographic responses of a threatened, low-density ungulate to annual variation in meteorological and phenological conditions

Demographic responses of a threatened, low-density ungulate to annual variation in meteorological and phenological conditions

Full Issue PDF

Leveraging AI to Estimate Caribou Lichen in UAV Orthomosaics from Ground Photo Datasets

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