Title
Testing hypotheses of bison population decline (1970-1999) in Wood Buffalo National Park: Synergism between exotic disease and predation
Author(s)
Joly D.O., Messier F.
Published
2004
Publisher
Canadian Journal of Zoology
Abstract
One hypothesis to explain the decline of bison (Bison bison (L., 1758)) abundance in Wood Buffalo National Park, Canada, is the "disease- predation" hypothesis where tuberculosis (Mycobacterium bovis Karlson and Lessel, 1970) and brucellosis (Brucella abortus (Schmidt, 1901)) reduce bison survival and reproduction, thus shifting bison abundance from a high-density, food-regulated equilibrium to a low-density, predator-regulated equilibrium. We use historical data on bison abundance and stochastic population simulation to examine this hypothesis. A decline in only one area of the park would discount disease as a factor, because exotic disease is present throughout the park; however, we found that decline rates were similar in the two main populations of bison. Using simulation, we found a high (68.5%) probability that a tuberculosis- and brucellosis-infected bison population experiencing predation by wolves (Cams lupus L., 1758) would stabilize at low densities (<0.83 bison/km2), which increased to 93.6% when anthrax and drowning were considered to be mortality sources. In the absence of tuberculosis and brucellosis, there was a low probability that bison would persist at this low density (<8%). These simulations suggest that an interaction between tuberculosis, brucellosis, and predation may account for the decline of bison abundance in Wood Buffalo National Park from 1970 to 1999.
Keywords
Bacteria; Computer simulation; Diseases; Ecology; Ecosystems; Population statistics; Probability; Random processes; Reproduction; Stochastic population simulation; Tuberculosis; Biodiversity; brucellosis; population decline; predation; synergism; tuberculosis; ungulate; Canada; North America; Western Hemisphere; Wood Buffalo National Park; World; Anthrax; Bacteria (microorganisms); Bison; Bison bison; Brucella; Brucella melitensis biovar Abortus; Bubalus; Canidae; Canis; Canis familiaris; Canis lupus; Mycobacterium; Mycobacterium bovis
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PUB11102