2026-02-05 カナダ・ブリティッシュコロンビア大学(UBC)
<関連情報>
- https://news.ubc.ca/2026/02/wolf-reduction-boosts-caribou-survival-in-rugged-terrain/
- https://wildlife.onlinelibrary.wiley.com/doi/10.1002/jwmg.70143
マウンテンカリブーの新生児死亡率:オオカミ削減計画開始時の捕食パターン Neonate mortality in mountain caribou: Patterns of predation during onset of a wolf reduction program
Tazarve Gharajehdaghipour, Marie Auger-Méthé, A. Cole Burton
The Journal of Wildlife Management Published: 23 November 2025
DOI:https://doi.org/10.1002/jwmg.70143
Abstract
Caribou (Rangifer tarandus) calf mortality during the neonatal period is commonly attributed to predation, particularly by gray wolves (Canis lupus). However, neonate mortality remains understudied in mountain caribou, despite increasing wolf reduction programs. We used an individual-based movement method to infer parturition and neonate mortality from adult female telemetry data (78 individual-years), supplemented with 3 years of camera trap data (89 cameras), to examine changes in neonate mortality rates, timing, and locations before (2012–2014) and after (2020–2021) wolf reduction, across 2 calving areas (one rugged, another gradual) for the Itcha-Ilgachuz subpopulation in British Columbia, Canada. Given the likely difference in the timing of wolf–neonate overlap between calving areas, we hypothesized that wolf predation would be additive to other mortality sources typically affecting younger neonates (e.g., grizzly bear [Ursus arctos] predation) in the rugged area, but compensatory in the gradual area. Accordingly, we predicted that reducing wolves would increase survival and lower the average mortality age for neonates in the rugged area, with smaller gains in survival and minimal change in average mortality age in the gradual area. After wolf reduction, survival increased 41% in the rugged area but did not improve in the gradual area, resulting in no overall increase in survival at the subpopulation level. Average mortality age decreased in the rugged area from approximately 14 days to 8 days, coinciding with the peak in camera detections of grizzlies and wolverines (Gulo gulo), and remained at approximately 9 days in the gradual area. Mortalities before wolf reduction (i.e., those more likely caused by wolves) were more strongly associated with anthropogenic linear features and treed valley bottoms. Our findings highlight the value of considering habitat-specific mechanisms influencing calf mortality and integrating indirect approaches to address knowledge gaps in prey–predator dynamics.
