Woodland caribou continue to be a lightening rod for industry, government, and public interest because of their threatened status and the fact that there is clear evidence that many populations are declining in Alberta and other parts of Canada. The working hypothesis has been that caribou declines are linked to forest harvesting because these activities have increased alternate prey (moose) that in turn, has increased wolf populations. Higher wolf numbers result in an increase in the spatial overlap between caribou and wolves that in turn, increases caribou mortality. Our studies in northeastern Alberta suggest that the basic moose-wolf-caribou system may be getting more complicated. It is possible that deer have become an important alternate prey for wolves along with moose as aerial surveys conducted by government personnel suggest that deer have increased and expanded their range significantly. In addition, coyotes represent a potential new predator on caribou calves and the creation of linear features during hydrocarbon exploration and extraction may enhance hunting efficiency in caribou range for a number of predators. A key uncertainty relates to whether the mechanisms of increased spatial overlap of predators and caribou are local or regional in scale. In other words, is increased overlap between caribou and their predators caused by regional predator populations increasing outside caribou habitat but using human-created linear features to increase access and improve hunting efficiency or to a local response whereby deer and moose have increased in caribou range to levels capable of supporting resident individuals/packs of wolves and coyotes?
We will adopt two approaches to answer this question. First, we will do in-depth studies of two caribou herds that have been well-studied in the past 10 years. David Latham is working on the West Side of the Athabasca River (WSAR) range where we previously studied the spatial overlap between wolves, moose and caribou 10 years earlier. At that time the caribou population was considered stable, there were few deer in the region, and there was little overlap between wolves and caribou. Since then oil and gas development on the range has increased as has forest harvesting in the surrounding region. Latham will test the hypothesis that these changes have compromised the spatial separation strategy of the WSAR herd. He is in the first year of a three-year field program designed to:
1) determine the current degree of spatial overlap between caribou and moose, deer, coyotes and wolves
2) examine how relative densities of all species have changed on and around the range in the last 10 years
3) determine if and how wolf packs are distributed in the peatland complexes that used to be exclusive to caribou
4) determine how wolves and coyotes currently divide space and food resources in this area.
The Little Smoky herd, located in west-central Alberta, is presently estimated to number approximately 60-80 animals and studies of adult mortality and annual calf recruitment since 1990 have indicated a steep decline in herd size during this period. A combination of forest harvesting and the accumulation of extensive linear disturbances (e.g., seismic cutlines, roads and pipeline corridors) are thought to have contributed significantly to the decline of this herd. In 2004, Suncor Energy and Conoco-Phillips Canada made a two-part funding commitment towards habitat recovery actions for the Little Smoky caribou herd as part of their application to construct a 100 km gas pipeline in the Little Smoky range. One of the goals of the Little Smoky habitat restoration pilot is to apply restoration techniques to speed the recovery of historical man-made linear features on a portion of the Little Smoky Range so that the negative effects of these features on caribou use of their habitat are reduced, including reducing permeability of habitat to predators. The Chair has collaborated with the Little Smoky Range restoration team to create an experimental design and monitoring program to assess whether or not restored lines discourage wolf use and how this in turn, affects caribou habitat use.
We will study the two herds in a similar fashion. Female caribou are fitted with conventional VHF collars for survival and calf recruitment calculations. Some animals receive GPS collars that provide detailed information on habitat selection and response to linear features. The same is done for wolves in the study area. Predator diet will be assessed via scat collection and analysis. Scats will be collected opportunistically and by directed searches (i.e. whilst conducting ungulate pellet surveys) throughout the ranges. Resource selection functions will be developed to examine how various landscape attributes affect the relative probability of habitat and linear feature use.
Additional management actions are also being considered for the Little Smoky Herd including predator management (reduction), alternate prey management (aggressive hunting quotas to reduce deer and moose), and calf protection (pregnant females are housed in pens until they give birth and calves have reached two weeks of age). The Chair will work with government and industry partners through involvement in the Alberta Caribou Committee to plan how these treatments can be implemented to maximize learning in an active adaptive management sense.
The caribou work will be done as a major collaborative effort between the Chair, the Alberta Caribou Committee (ACC), and Dr. Fiona Schmiegelow (Department of Renewable Resources). The caribou monitoring (collaring, survival and recruitment) and implementation of experiments will be handled by the ACC as part of their mandate to develop and implement recovery plans for caribou herds within the province. Dr. Schmiegelow has led a research program on caribou and wolves in the Little Smoky region for the past 5 years and she and the Chair have served in an advisory role for the range recovery plan developed by Suncor and Conoco-Phillips.
We will couple the detailed study of two herds with broad-scale comparisons of multiple herds through collaborations with studies currently underway or planned for 15-20 herds in Alberta, British Columbia, Yukon, and Northwest Territories. These herds vary in the level of industrial activity in and around each range. Each study is collecting data on caribou adult survival and recruitment and the Chair will undertake a coordinating role to have each project also collect wolf, coyote, deer, and moose relative abundance. This broad-scale information will allow us to determine if there may be possible thresholds to development that trigger the breakdown in spatial separation between caribou and their predators