Probability of Range Occupancy by Woodland Caribou during Winter in the Muskwa-Kechika Management Area, British Columbia
Occupancy by caribou is not formally known or recorded for some locations within the Muskwa-Kechika Management Area (MKMA) in northern British Columbia even though, anecdotally, caribou are known to occur in those places. To assist execution of population surveys, we applied a habitat model to forecast the relative probability of occupancy by caribou in high-elevation areas during winter in the MKMA. The MKMA is located in north-eastern BC, its’ extent ranging approximately from 56º22’N to 59º57’N and 122º47’W to 128º56’W encompassing an area of 6.4 million hectares. We determined that more than half of the MKMA was above 1,300m asl (57% or 3.48 Mha) and that 2.48 Mha (71% of the high elevation and 39% of the entire MKMA) was apparently capable of providing winter range for woodland caribou. To assess the model results, we collected 2,388 observations of woodland caribou when they occurred at high-elevations during winter including that from 14 individual radio-collared caribou and 9 different population surveys. Although a disproportionate majority of the observations were for caribou using the best of the high elevation range, use of poor habitat was still 24% of the sample.
We concluded that the model was not able to distinguish high-valued winter range sufficient to greatly raise the efficiency of population surveys in the MKMA. This result was contrary to previous applications of the model in north-central BC where we were successful in formally designating Ungulate Winter Range for woodland caribou. If use of the model in the MKMA is to be investigated further, we suggest focusing on setting new parameters for the snowfall factor in the model which may help refine the prediction of high-elevation winter range to the point where is will be operationally of benefit. Also, more care should be taken to insure test observations from caribou are from behavior types that are relevant to the habitat being predicted.