Summary
The Whooping Crane was designated as “Endangered” Species in 2000 by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC). The species at risk act (SARA) prescribes delineation of critical habitat for this species. This work contributes to and supplements related recovery and conservation efforts. A comprehensive population and habitat viability analysis for the Whooping Crane in the Wood Buffalo National Park and surrounding areas has been conducted. Metapopulation and individual-based, spatially explicit population models were used to asses demographic viability, minimum viable population size and critical habitat for the Whooping Crane population. The results indicate that the Whooping Crane population is demographically viable and self-sustaining. Presuming that habitat is available for and accessible to 500 breeding pairs over 100 years, the calculated extinction risk may be less than one percent. Under such conditions the minimum viable population size over a time span of 100 years is estimated to be 40 breeding pairs, which is 20 percent less than the actual number of breeding pairs in the Wood Buffalo National Park. However, actual habitat amount and fragmentation may limit future population growth of the Whooping Crane. If the Whooping Crane would be confined to its currently occupied habitat (about 200 km², 50 territories), the population would face an extinction risk of about 13 percent together with a steady population decline. In contrast, when all identified suitable habitat within the Wood Buffalo National Park (about 927 km², 231 territories) remains suitable and available for the Whooping Crane, the population may double within 100 years without being endangered to extinction. The potential for population growth may increase when all suitable habitat within and outside the borders of the Wood Buffalo National Park (1615 km², 403 territories) are conserved. The predicted population growth, however, is far less than the observed growth rate of 3.5 percent per year in the past. The results indicate that the actual growth rate for the Whooping Crane population may be limited by the fragmentation and dispersion of breeding habitat. Some of the habitat fragments may be too small and too far apart to be steadily utilized and colonized by the Whooping Crane, whose observed natal dispersal range is limited to 55 km. The model predicts average habitat utilization rates of 30 percent and maximum habitat utilization of 75 percent over 100 years. The identified suitable habitat within the boundaries of the Wood Buffalo National Park may be sufficient to support a viable and self-sustaining population of the Whooping Crane. However, the growth rate of the population may significantly increase when habitat outside the park boundaries remains intact and suitable.