Shane P. MAHONEY, Keith P. LEWIS, Kim MAWHINNEY, Chris MCCARTHY, Scott TAYLOR, Doug ANIONS, James A. SCHAEFER, and David A. FIFIELD
CWBM 5 (2): 46-59.
Correspondence: Shane Mahoney, Conservation Visions Inc., P.O Box 5489, Station C, 354 Water Street, St. John’s, Newfoundland, A1C 5W4, Canada. E-mail: firstname.lastname@example.org
Caribou (Rangifer tarandus) and other northern ungulates are increasingly exposed to snowmachine activity, but the implications of such exposure for energetics and habitat use are not fully understood. We assessed the influence of snowmachine exposure on the energy balance and habitat selection of caribou in Gros Morne National Park, Newfoundland, Canada. We assessed habitat selection of radio-collared females at 2 spatial scales, within the population range and the home range. Based on field observations of caribou reactions to provocation by snowmachine, we modelled the energetic costs of disturbance as 1 event and extrapolated its effects on body mass during winter. During winter, females exhibited apparent preference for snowmachine trails at the scale of the population range, but neither preference nor avoidance at the scale of the home range. This broad-scale pattern likely reflects the spatial association of trails with lowlands and the more favourable nival conditions there. The energetic cost of 1 snowmachine encounter was negligible; we surmise it would require far more encounters than are likely to produce a significant and harmful loss in body mass. We conclude that the lack of response to snowmachines may represent habituation, a lack of snowmachine-free alternative habitat, and/or risk-prone foraging by this population.
Key Words: Caribou, Disturbance, Energetics, Habitat Selection, Snowmobile.