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Gates,
C.C., N.C. Larter and P.E. Komers. 1991. Size and composition of the
Mackenzie wood bison population in 1989. 24 pp.
ABSTRACT
Wood
bison introduced to the Mackenzie Bison Sanctuary in 1963 increased at a
mean exponential growth rate of r = 0.215 during the period 1964
to 1987.
The rate of population growth has slowed since 1975.
However, with the continued increase in herd size a controlled
hunt was allowed for the first time during the 1987/88 hunting season.
Four bison were killed from a quota of 20 males.
Twenty males were killed in 1988/89 when the quota was increased
to 40 males.
A census was conducted in March 1989, employing a combination of
total counts and sampling to estimate bison numbers.
The number of bison estimated in the sampled strata was 1048 +
229 (s.e.). Total population size was estimated to be 2431 bison based
on census results.
The calculated 95% confidence range for the annual exponential
rate of increase (r) between 1987 and 1989 based on the census
estimate was 0.07 to 0.26.
A
demographic model was constructed to provide alternative estimates of
population size and rate of increase, based on the 1987 total count and
demographic parameters.
With this method the estimated size of the herd in March 1989 was
2040 and a growth rate for 1988/89 of r = 0.11 was calculated,
accounting for hunting losses and estimated natural mortality.
The accidental loss of 177 bison caused by deteriorating ice on
Falaise Lake in May 1989 resulted in a total population of 1863 in June
1989 and a net rate of increase of r = 0.02 for 1988/89.
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