Annual re-habituation of calving caribou to oilfields in northern Alaska: implications for expanding development

• Published in: Canadian Journal of Zoology
• Main Authors: Haskell, Shawn P., Ballard, Warren B.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 2008
• Subjects: Animal Science and Zoology; Ecology, Evolution, Behavior and Systematics; caribou; Rangifer tarandus; Alaska
• Online Access: http://dx.doi.org/10.1139/z08-039; http://www.nrcresearchpress.com/doi/full-xml/10.1139/Z08-039; http://www.nrcresearchpress.com/doi/pdf/10.1139/Z08-039

Previous research led to hypotheses that calving caribou ( Rangifer tarandus granti J.A. Allen, 1902) in north Alaskan oilfields habituated to human activities: (i) across years and (ii) annually after spring migration (i.e., re-habituation). We used predictor variables of year and a spring snowmelt index to evaluate weight of evidence for these competing hypotheses. Response variables were calf percentage and sighting rate of calving caribou along a high-traffic road system from 1982 to 1990 and 2000 to 2002. We also considered local calf percentage and caribou density, determined by aerial surveys, for respective response variables. We found no evidence of habituation across years. We found two more lines of evidence (one strong and one weaker) for re-habituation within years during calving periods. Post hoc models suggested a further tolerance response exhibited by caribou; more data are needed. Even when snow melted early and calving caribou were most habituated among years, caribou and calves were under-represented near the road system. Investigation of a traffic-rate effect seems warranted. However, habitat selection and forage availability should be considered when interpreting avoidance behaviour at a larger spatial extent. We contend that the behavioural adaptability of calving caribou exhibited in existing oilfields was contingent on the no-hunt policy.