Caribou Mortality and Disease Prevalence in West-central Alberta

Authors
Laura Finnegan
Bryan Macbeth
Doug MacNearney
Karine Pigeon
Terry Larsen
Helen Schwantje
Susan Kutz
Resource Date:
2016
Page Length
39

Woodland caribou are in decline across their range and although the proximate cause of decline is unsustainable rates of predation, health is increasingly recognised as a factor that may contribute to survival and reproduction in caribou. The goal of this two year project is to increase understanding of predator risk and caribou health in west-central caribou herds. In the first year of this research project our aims were 1) to use caribou mortality site visits and existing mortality databases to address the current knowledge gap surrounding predators and landscape attributes associated with caribou mortalities in west-central Alberta, and 2) to initiate the first detailed health assessment of west-central caribou herds.
Over a three year period we visited 21 caribou mortalities; 8 within 48 hours of the mortality event and 8 within 2 weeks of the mortality event. Using standardized site investigation, necropsy and sampling protocols we attributed 12 of these mortalities to probable predation, three to accidents, three to disease/health and three as unknown. Of the 12 mortalities we attributed to predation four were cougar, three were grizzly bear, two were wolf and three had multiple predator signs. Our preliminary analysis assessing the spatial distribution of mortalities revealed that
mortality patterns differed across seasons, and between protected and unprotected areas. Generally mortalities occurred in wet areas and closer to seismic lines, and we found a higher probability of mortality risk on steep slopes, at lower elevations during migration and summer, and in valleys during winter. Overall these results suggest that caribou mortalities occur in habitat preferred by a range of predators.