Northern Prairie Wildlife Research Center
Upland forests in the region are mixed coniferous-deciduous. Infertile soils and poor drainage limit agriculture in much of the primary range of wolves. Lakes are common. About 77% of the primary range is classified as forested land use, whereas forested in the other portions of the range varies between 21 and 86% (G. L. Radde, personal communication). Human population in the primary zone declined from 1970 to 1986, while it increased in each of the other zones where farm density is higher.
White-tailed deer (Odocoileus virginianus) are the primary prey of wolves in all occupied areas of Minnesota, but wolves also eat moose (Alces alces), beaver (Castor canadensis), and snowshoe hares (Lepus americanus; Frenzel 1974; Van Ballenberghe et al. 1975; Fritts and Mech 1981; Fuller 1989). In our studies, deer populations seemed to be at least as high in areas where livestock were produced as in more remote forested areas. Reliable estimates of deer populations have been available for the wolf-inhabited areas of Minnesota since 1982, and they showed no substantial changes during 1982-86. However, decreases of 8 to 24% were indicated in some deer management subunits in the southern and southwestern part of the wolf range where several of the farms are located (Joselyn et al. 1988).
No data were available on wolf population trends in the main agricultural areas of Minnesota during the present study. Although the over all population seemed to be generally stable, with essentially all habitat filled, our observations suggested that some increase may have occurred in the western part of the range, especially in Wolf Management Zone 5 (Fig. 1a). The total Minnesota population was estimated at 1,000-1,200 in the mid-1970's (USFWS 1978) and at 1,235 in 1979 (Berg and Kuehn 1982). Some statewide increase since 1979 is likely.
Wolves occasionally prey on Minnesota livestock wherever the two coexist, but most depredations occur in north-central and northwestern counties where farm density and livestock production is highest within the wolf s range. Fritts (1982) estimated that there were about 12,230 farms (at least 80% having some livestock) in the wolf range in 1979, containing 234,000 cattle, 91,000 sheep, and an unknown number of turkeys, swine, horses, goats, chickens, ducks, and geese. Recalculation of the number of farms based on more recent census data (1982 v. 1976; Minnesota Agricultural Statistics 1984) showed about 7,200 farms. This figure is lower than the previous one because a more restricted wolf range was used in computations of farm numbers-based on a refinement of the known wolf distribution (Mech et al. 1988a); and a real decline occurred in farm numbers in wolf range estimated at 13% from 1976 to 1982. A further decline in farm numbers from 7,200 to 6,800 was revealed by the 1987 census data, but total land area in farms declined only 1%. Farm size averaged 141.6 ha in the wolfrange during the study, tending to be larger in northwestern counties and smaller in northeastern counties.