Application of Herd Viability Models for Boreal Woodland Caribou (Rangifer tarandus caribou) to a Northern Mountain Caribou Herd

Posted on Oct 10, 2013


Donald G. REID, Shawn R. FRANCIS, and Terry ANTONIUK

Correspondence: Donald G. Reid, Wildlife Conservation Society Canada, P.O. Box 31127, Whitehorse, Yukon, Y1A 5P7, Canada. Email:

Received 22 July 2013 – Accepted 10 October 2013


Caribou (Rangifer tarandus) herds of the northern mountain population in British Columbia and Yukon are facing increased human development and habitat alteration. Managers need to better understand at what stage these changes will become a conservation issue. Historical declines in numerous herds of the Boreal Woodland Caribou population prompted development of three models relating herd viability to human footprint and proportion of the land base changed to early-seral conditions by natural or human disturbance. We applied these models to the range of a northern mountain herd, the Carcross Caribou Herd (CCH), in southcentral Yukon, to understand whether and how the boreal models could be used in a northern mountain context. Two of the boreal models, one based on Canada-wide (CW) herds and one on Alberta (AB) herds, produced reasonable approximations of the current population status of the CCH (increasing). The minimal secure patch area requirement of the third model, based largely on Northwest Territories (NT) herds, could not be satisfied in the CCH range, if such secure patches necessarily include substantial winter range. The boreal models could not deal with the widespread and permanent shrub and sparsely vegetated habitats, often at high elevations, in Northern Mountain Caribou range, nor with the spatial segregation of the herds’ seasonal ranges, especially high-value winter ranges. The most robust conservation approach for Northern and Southern Mountain Caribou would be to develop new models based on the demographic and habitat profiles of numerous herds from these populations.

Key Words: Boreal, Caribou, Carcross, Northern Mountain, Population Viability, Rangifer tarandus.



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