State- and context-dependent applications of an energetics model in free-ranging bighorn sheep

Denryter, Kristin; German, David W.; Stephenson, Thomas R.; Monteith, Kevin L.

doi:10.1016/j.ecolmodel.2020.109349

Cited by 8 publications

(12 citation statements)

References 85 publications

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“…We find that energy-saving mechanisms such as peripheral heterothermy depend on body condition, age and reproductive state. Overall, a strong seasonal pattern overshadowed relatively small intraseasonal responses in heart rate, emphasizing the importance of evaluating individual state and seasonal context when studying energetics in free-living animals [ 79 ].…”

Section: Discussionmentioning

confidence: 99%

“…This effect was even greater in heavier females, suggesting that the cost of locomotion increases disproportionally with body mass and the intensity of activity [78]. Also, the reduced time spent active in winter is indicative of behavioural compensation to reduce energy deficits during periods of low food supply [79]. In summer, a higher proportion of time spent foraging [42] is likely to lead to a greater degree of rumen filling and, in turn, precipitate increased energy uptake and necessary increase in blood supply to the rumen [80] contributing to increased heart rates, even when resting.…”

Section: Discussionmentioning

confidence: 99%

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Determinants of heart rate in Svalbard reindeer reveal mechanisms of seasonal energy management

Trondrud

Pigeon

Albon

et al. 2021

Phil. Trans. R. Soc. B

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Seasonal energetic challenges may constrain an animal's ability to respond to changing individual and environmental conditions. Here, we investigated variation in heart rate, a well-established proxy for metabolic rate, in Svalbard reindeer ( Rangifer tarandus platyrhynchus ), a species with strong seasonal changes in foraging and metabolic activity. In 19 adult females, we recorded heart rate, subcutaneous temperature and activity using biologgers. Mean heart rate more than doubled from winter to summer. Typical drivers of energy expenditure, such as reproduction and activity, explained a relatively limited amount of variation (2–6% in winter and 16–24% in summer) compared to seasonality, which explained 75% of annual variation in heart rate. The relationship between heart rate and subcutaneous temperature depended on individual state via body mass, age and reproductive status, and the results suggested that peripheral heterothermy is an important pathway of energy management in both winter and summer. While the seasonal plasticity in energetics makes Svalbard reindeer well-adapted to their highly seasonal environment, intraseasonal constraints on modulation of their heart rate may limit their ability to respond to severe environmental change. This study emphasizes the importance of encompassing individual state and seasonal context when studying energetics in free-living animals. This article is part of the theme issue ‘Measuring physiology in free-living animals (Part II)’.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Determinants of heart rate in Svalbard reindeer reveal mechanisms of seasonal energy management

Trondrud

Pigeon

Albon

et al. 2021

Phil. Trans. R. Soc. B

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“…However, Spitz et al (2020) also observed that forage availability on both high and lowelevations ranges helped to explain the frequency of migrant and resident behaviors. They concluded that migrant SNBS prioritize access to forage at the cost of increased predation risk, while residents minimize predation risk but incur increased energetic costs imposed by limited access to forage and greater thermoregulatory demands (Johnson et al, 2013;Spitz et al, 2020;Denryter et al, 2021a). While our results suggest that avoidance of snow may be of greater importance for migrants than access to forage, discrepancies between studies may result from our quantification of vegetative biomass.…”

Section: Habitatmentioning

confidence: 58%

Seeing Is Be-Leaving: Perception Informs Migratory Decisions in Sierra Nevada Bighorn Sheep (Ovis canadensis sierrae)

et al. 2022

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Seasonal migration is a behavioral response to predictable variation in environmental resources, risks, and conditions. In behaviorally plastic migrants, migration is a conditional strategy that depends, in part, on an individual’s informational state. The cognitive processes that underlie how facultative migrants understand and respond to their environment are not well understood. We compared perception of the present environment to memory and omniscience as competing cognitive mechanisms driving altitudinal migratory decisions in an endangered ungulate, the Sierra Nevada bighorn sheep (Ovis canadensis sierrae) using 1,298 animal years of data, encompassing 460 unique individuals. We built a suite of statistical models to partition variation in fall migratory status explained by cognitive predictors, while controlling for non-cognitive drivers. To approximate attribute memory, we included lagged attributes of the range an individual experienced in the previous year. We quantified perception by limiting an individual’s knowledge of migratory range to the area and attributes visible from its summer range, prior to migrating. Our results show that perception, in addition to the migratory propensity of an individual’s social group, and an individual’s migratory history are the best predictors of migration in our system. Our findings suggest that short-distance altitudinal migration is, in part, a response to an individual’s perception of conditions on alterative winter range. In long-distance partial migrants, exploration of migratory decision-making has been limited, but it is unlikely that migratory decisions would be based on sensory cues from a remote target range. Differing cognitive mechanisms underpinning short and long-distance migratory decisions will result in differing levels of behavioral plasticity in response to global climate change and anthropogenic disturbance, with important implications for management and conservation of migratory species.

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“…An alternative explanation for vacillating migration is that it represents seasonal habitat use or forays rather than a type of migration; however, high-and low-elevation ranges were separated by hundreds to thousands of meters in elevation (Appendix S1: Fig. S1B) and~4-12 km-distances that were~3-12 times greater than the high end of the 95% confidence interval (CI) of daily movements of Sierra bighorn during winter (Denryter et al 2021). Regardless of whether vacillating migration is a true migratory behavior or seasonal habitat use, it differed significantly from other types of movement behavior in our study area.…”

mentioning

confidence: 99%

“…S1B) and ~4–12 km—distances that were ~3–12 times greater than the high end of the 95% confidence interval (CI) of daily movements of Sierra bighorn during winter (Denryter et al. 2021 ). Regardless of whether vacillating migration is a true migratory behavior or seasonal habitat use, it differed significantly from other types of movement behavior in our study area.…”

mentioning

confidence: 99%

Broadening the migratory portfolio of altitudinal migrants

Denryter

Stephenson

Monteith

2021

Ecology

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State- and context-dependent applications of an energetics model in free-ranging bighorn sheep

Cited by 8 publications

References 85 publications

Determinants of heart rate in Svalbard reindeer reveal mechanisms of seasonal energy management

Determinants of heart rate in Svalbard reindeer reveal mechanisms of seasonal energy management

Seeing Is Be-Leaving: Perception Informs Migratory Decisions in Sierra Nevada Bighorn Sheep (Ovis canadensis sierrae)

Broadening the migratory portfolio of altitudinal migrants

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