Excellent review of the literature on wolverines as of 1994. Too much to summarize here, but here are some notable excerpts:

Wolverine Distribution
Overall
Banci (1994) reviews the historical distribution of wolverines in North America (p. 102). She reports that in the western U.S., "the presettlement geographic range of wolverines extended southward from Canada through the montane ecoregions to Arizona and New Mexico (Hash 1987)." She then qualifies this statement: "However, it is not known whether these southern occurrences represent reproducing populations or dispersers." Banci concludes this section: "The northward retreat of wolverine distribution in the United States began in the 1840's (Hash 1987). Today, wolverines occur in Montana, Idaho, Wyoming, Colorado, Washington, Oregon, and California."
Regarding historical wolverine presence in the Lake States and High Plains, Banci (1994) reports:
"Wolverines are thought to have had a wide presettlement distribution in the Great Lakes region, although only in small numbers (deVos 1964). They have been absent from this region since the early 1900's (deVos 1964) and are extirpated from North Dakota, Minnesota, Wisconsin, Michigan, and Iowa (Hamilton and Fox 1987)."
Banci (1994) does not discuss wolverine distribution in the eastern states, but mentions its presence in Labrador and Quebec (Kelsall 1981), and that they were extirpated from New Brunswick in the second half of the 19th century (Seton 1929).

Rocky Mountains
According to Banci's 1994 chapter for FS Gen. Tech Report RM-254, the species was believed to be near extirpation in Wyoming in the 1920s; however she reports, "Newby and McDougal (1964) believed wolverine had expanded their range into the southwestern part of the state, as did Hoak et al. (1982). There are 100 records available from 1961 to 1991, all in the western third of the state (unpublished data in Maj and Garton 1992)" (p. 103).
"Johnson (1977) suggested that wolverines were present in the Cascade Range between 1890 and 1919) but absent or rare throughout the state from 1920 through 1959" (p. 103). Twenty-eight Wolverines were recorded for the state between 1970 and 1990 (p. 103). "Kebbe (1966) referred to unverified reports that indicated that a remnant population existed in remote areas of the Cascade Range There are 23 records from 1981 to 1992, compared to 57 records from 1914 to 1980" (p. 103).

Sierra & Northwest
According to Banci's 1994 chapter for FS Gen. Tech Report RM-254, the wolverine was believed to be near extirpation in California by the 1920s, but since then have partially recovered. "Yocum (1973) believed that wolverines were becoming established in the mountainous areas of northwestern California, from `surviving nuclei' to the north. The current range includes a broad arc from Del Norte and Trinity counties through Siskiyou and Shasta counties, and south through the Sierra Nevada to Tulare County" (p. 103). This is consistent with evidence cited by White and Barrett (1979), who estimated a population of 50-100 wolverines in the state.
Banci expressed concern that the California population may be becoming isolated, and that this has already occurred for wolverines in Colorado: "Wolverines in the Colorado Rocky Mountains ecoprovince are isolated from areas to the north by the Central Rocky Mountain and Wyoming Basins" (p. 104).

Range requirements
Wolverines, it appears, exist at even lower densities than other mid-sized carnivores (Banci, 1994). "Not a hunter, [the wolverine] depends on wolves and other predators to provide carrion" (Banci, 1994; p. 100). Wolverine diet can also be provided by avalanches, starvation, and other factors.
How much space does a wolverine need to meet its needs? Banci (1994) wrote: "Home ranges of adult wolverine in North America range from less than 100 km2 to over 900 km2. . . The variation in home range sizes among studies partly may be related to differences in the abundance and distribution of food" (Banci, 1994, p. 117). She goes on to cite the wolverine situations in "the southwest Yukon and in southcentral Alaska" and the differing situation in salmon spawning areas (Banci, 1994, p. 117). "In northwest Alaska, food levels were particularly low and dispersed because of the absence of overwintering caribou and home ranges of wolverine were larger than all others reported (Magoun, 1985)" (Banci, 1994, p. 117). Thus, comparatively small home ranges may reflect more abundant food sources, larger ones scarcer food.

Reproduction
Wolverines are not prolific reproducers: "Reproductive rates are low and sexual maturity delayed, even in comparison with other mammalian carnivores" (Banci, 1994, p. 108). Years when food is scarce may inhibit litter production if females are in poor nutritional condition. (Banci, 1994). Some observers have speculated that lack of suitable denning habitat may also inhibit reproduction.
"Wolverines exhibit delayed implantation, during which development of the embryo is arrested at the blastocyst stage. Implantation in the uterine wall can occur as early as November (Banci and Harestad 1988) or as late as March (Rausch and Pearson 1972)" (Banci 1994, p. 104).
Kits are weaned at 9-10 weeks (Banci, 1994), and grow at a faster rate than many other mammals, reaching adult size by seven months of age (Banci, 1994, citing Magoun, 1985). "Iversen (1972) suggested that the rapid increase in total heat production during the early phase of growth resulted from a faster growth of the high energy-producing tissues compared to other mammals This, in turn places high energetic demands on mothers and can affect female reproduction in the immediate future" (Banci, 1994). Regarding their age of first reproduction, female wolverines do not breed during their first summer, while males remain sexually immature until after their first two years (Banci, 1994).

Habitat needs
General
"habitat is probably best defined in terms of adequate year-around food supplies in large, sparsely inhabited wilderness areas, rather than in terms of particular types of topography or plant associations" (Kelsall 1981). She qualifies this finding by pointing out that while this is generally true at the landscape scale, stand-level habitat use by wolverines in forests has not been adequately investigated. (Banci, 1994, p. 114)

Denning habitat needs
Banci compiled characteristics of wolverine den sites in North America (1994):
"Information on the use of natal dens in which the kits are born by wolverines in North America is biased to tundra regions where dens are easily located and observed. These natal dens typically consist of snow tunnels up to 60 m in length. Northern European dens have been noted in boulder fields and talus slopes. . . . Natal dens may be located near abundant food, such as cached carcasses or live prey (Haglund 1966, Rausch and Pearson 1972, Youngman 1975)" (Banci, 1994). Wolverine dens, in the northern hemisphere have included hollow trees, holes under tree roots, overturned trees.
"Rarely, kits have been found relatively unprotected, on branches and on the bare ground. . . . abandoned beaver lodges . . . old bear dens, . . . creek beds, under fallen logs, under the roots of upturned trees, or among boulders and rock ledges" (Banci, 1994).

Habitat security
"If females are disturbed they will move their kits, often to what appear to be unsuitable den sites." While the kits are still too young to travel, the female leaves them in a "rendezvous site" and forages alone. "Wolverine mothers go to great lengths to find secure dens for their young, suggesting that predation may be important" (Banci, 1994).
The level of human activity is clearly a primary factor for wolverine habitat (Banci, 1994):
Within its geographic range, the wolverine occupies a variety of habitats. However, a general trait of areas occupied by wolverines is their remoteness from humans and human developments.
Banci (1994) wrote:
"Refugia, large areas that are not trapped and free from land-use impacts, can serve as sources of dispersing individuals and have been shown to be effective at ensuring the persistence and recovery of fisher and American marten populations (deVos 1951, Coulter 1960). The persistence of wolverine populations in Montana, despite years of unlimited trapping and hunting, was attributed solely to the presence of designated wilderness and remote, inaccessible habitat (Hornocker and Hash 1981). Wolverines persisted in southwestern Alberta despite their extirpation elsewhere in the province, largely because of the presence of large refugia in the form of national parks" (Banci, 1994, p. 108).
Yet, Banci (1994) also noted some inconsistencies in the general truth that wolverines are intolerant of people:
"Human presence alone is not a deterrent to the presence of wolverines, as evidenced by their feeding in garbage dumps in northern Canadian communities. If large tracts of undeveloped and unroaded habitat are essential, why do wolverine occur in the logged forests of the Sub-Boreal Interior of British Columbia and in the habitats criss-crossed with seismic lines on the Boreal Plains? (pp. 100-101)

Mortality
Banci reports: "Over most of its distribution, the primary mortality factor for the wolverine is trapping. In telemetry studies, trapping has accounted for over half of all mortalities"