SIZE, TREND, DISTRIBUTION AND CONSERVATION OF THE BROWN BEAR URSUS-ARCTOS POPULATION IN SWEDEN

The density of adult (greater than or equal to 3 years) female brown b ears Ursus arctos was estimated in two areas of Sweden from ratios of radio-marked and unmarked females consorting with radio-marked adult m ales during the breeding season. The resulting densities were 1.2 +/- 0.81 (95% confidence interval) adult females/1000 km(2) in a northern study area and 1.06 +/- 3.44 adult females/1000 km(2) in a southern ar ea. These estimates were extrapolated to obtain a population estimate for Sweden using relative densities throughout the range of the specie s in Sweden, based on hunter-kill statistics, and observed rates of re production and juvenile and subadult survival. The total population in spring 1991 was estimated to be about 620 bears, with almost all fema les confined to four geographically separated areas, termed female cor e areas. A supplementary estimate, based on estimated kill rates of ad ult females in the study areas, was about 660 bears. Estimates based o n hunter kill rates of marked bears gave minimum and maximum estimates of about 300 and 900 bears, respectively. Although these are not conf idence intervals of the total population estimate, we believe that the true population size is included within these limits. Densities withi n the female cove areas varied from 50 to 100% of those in similar hab itats in European Russia. The bear population in Sweden appeared to ha ve increased at a stable rate of about 1.5% annually during the past 5 0 years. Mean annual rate of legal harvest during 1943-1991 was estima ted to be 55% (+/- 2.1% SD), suggesting a maximum sustainable rate of 7.0% for this population. The harvest increased at a rate of 9.6% annu ally during 1981-1991, and apparently was at the maximum sustainable l evel during 1987-91.