Predicting energy expenditure of caribou using activity counts: potential use in disturbance studies

Kitchens, Julie A.; White, Robert G.; Murphy, Stephen M.

doi:10.7557/2.13.2.1098

Cited by 2 publications

(1 citation statement)

References 8 publications

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“…Some energy expenditures (Fancy & White, 1985;Luick & White, 1986;White & Fancy, 1986) and seasonal energy budgets (Russell et al, 1993) have been documented for caribou and effects of energy and nutrition on fecundity have been estimated (Cameron et al, 1993;Gerhart et al, 1993). (Kitchens et al, 1993). All SELS from each day for a given animal were combined to estimate a time averaged sound level (L-p, ANSI S 12.40-1990).…”

Section: Introductionmentioning

confidence: 99%

Modeling energy and reproductive costs in caribou exposed to low flying military jet aircraft

Luick¹,

Kitchens²,

White³

et al. 1996

Ran

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We used simulation modeling to estimate the effect of low-flying military jet aircraft on the productivity of caribou. The base model (CARIBOU, CWS Whitehorse, Yukon Territory) uses daily intake and expenditure of energy to assess the condition of female caribou throughout the annual cycle. The activity budget of the model caribou was adjusted based on field observations of responses to noise disturbance. A subroutine was added that predicted the likelihood of conception based on fall body fat weight. Caribou responses to overflights were evaluated by equipping free-ranging caribou with radio collars and activity sensors that could distinguish between resting and active periods. Collared animals were exposed to 110 overflights by A-10, F-15 and F- 16 jet aircraft during late-winter, post-calving and the insect season. Noise exposure levels for individual animals either were measured directly with collar-mounted dosimeters or were estimated based on the proximity of the caribou to the aircraft during the overflight. A Time-averaged Sound Level (LT) was calculated from the total daily noise exposure for each animal and linear regression was used to evaluate the influence of daily noise exposure on daily hours spent resting. Results of these analyses then were used to modify the time budgets in the CARIBOU model. That is, if time spent resting declined, then time spent in the two rest classes (lying and standing) were proportionately redistributed into the three active classes (foraging, walking and running). Model simulations indicated that caribou increased forage intake in response to increased noise exposure, but it also predicted that increased noise exposure would cause a reduced accumulation of body fat. Because body fat in fall has successfully been used to predict the probability of pregnancy (see Gerhart et al, 1993), this relationship was used in the model. Preliminary model simulations indicate that increased noise exposure decreases the probability of pregnancy and that unfavorable environmental conditions (e.g., deep snow and severe insect harassment) exacerbate the situation. The threshold at which point the caribou fail to conceive has not been determined at this time, but appears to be well beyond the exposure to aircraft that caribou in the Delta herd are currently experiencing

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Section: Introductionmentioning

confidence: 99%

Modeling energy and reproductive costs in caribou exposed to low flying military jet aircraft

Luick¹,

Kitchens²,

White³

et al. 1996

Ran

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show abstract

Timing and synchrony of activity in caribou

Maier¹,

White²

1998

Can. J. Zool.

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Activity data were analyzed to assess activity patterns of caribou (Rangifer tarandus granti). We hypothesized that equal day and night activity, termed nychthemeral activity, would be expected if food constitutes a limiting resource for a highly gregarious species. To test this hypothesis, we investigated activity patterns of two caribou populations at the same latitude: one captive with no food limitation and the other wild and free-ranging in the Alaska Range in interior Alaska known to be at the end of a 3-year low plane of nutrition. For captive caribou, activity patterns were determined from focal-animal behavioural observations each month except May. Data were collected on wild caribou using activity-recording radio collars in each of three seasons: late winter, postcalving, and midsummer. Wild and captive caribou exhibited nychthemeral activity and did not time activity to sunrise or sunset. Wild caribou exhibited no among-group synchrony. Within-group synchrony was high in both herds. Wild caribou exhibited significantly fewer cycles of activity than captive caribou. Longer resting bouts in late winter, and longer active bouts postcalving and in midsummer for wild caribou, were interpreted as behavioural responses to ecological effects of limited food availability, with and without snow, and disturbance by insects.

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Predicting energy expenditure of caribou using activity counts: potential use in disturbance studies

Cited by 2 publications

References 8 publications

Modeling energy and reproductive costs in caribou exposed to low flying military jet aircraft

Modeling energy and reproductive costs in caribou exposed to low flying military jet aircraft

Timing and synchrony of activity in caribou

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