[Thanks to Keith Hammer of Swan View Coalition for this analysis; Swan View Coalition, 3165 Foothill Road, Kalispell, MT 59901, (406) 755-1379]

Mace and Waller's 1997 "final" South Fork Grizzly study report has been issued under the title "Final Report: Grizzly Bear Ecology in the Swan Mountains, Montana,". Some chapters from the final report have since been published in peer reviewed jounals in various forms.

In a nutshell, the report greatly softens the importance and emphasis on the need for road obliteration, placing more importance on reducing traffic volume. The importance of "roadless" core area is still stressed, although the percentage found on average in female home ranges is lowered from 68% to 60% from previous reports (which is where permanent closure / obliteration of roads still applies tosome extent).

Mace, Waller and other agency biologists participating in the Interagency Grizzly Bear Committee, however, have proposed new road management standards that depart significantly from standards based on earlier South Fork study findings and from the findings of the final report itself. Dr. Lee Metzgar in November 1998 issued adetailed, highly critical review of their proposal and their proposal is currently before a peer review panel.

The South Fork population was initially described as a "tenuously stable source-sink" situation, with bears from the core area suffering high mortality, primarily around the perimeter (with the exception being mistaken identity kills during black bear hunting season in the Bob Marshall Wilderness). Alerted by Dr. Metzgar to an error in the calculated reproductive rate, however, Mace and Waller issued in September 1998 an errata sheet to page 112 of their final study:

"An error in calculating the reproductive rate for 6 female grizzly bears was discovered [] The actual reproductive rate for female cubs was 0.261 not 0.389. This change in reproductive rate served to change the mean estimate of lambda from 1.009 down to 0.977.

The probability of the population declining was 69%, stable to increasing 31%, and increasing 27%. The annual exponential rate of increase (r) was -0.02 [], indicating it would take [approximately] 30 years to observe a population halving, given long-term stability of vital rates." In his November 1998 critique, however, Dr. Metzgar notes that Mace and Waller incorrectly define "stable to increasing" as populations having a lambda of 0.995 to 1.0, rather than correctly defining populations with a lambda <1.0 as declining. Dr. Metzgar concludes that Mace and Waller's calculations actually produced a 73% probability that the population was declining with lambdas <1.0 and a 27% probability that the population was stable or increasing with lambdas of or = 1.0.

The study findings are summarized in Chapter 10 and include the following highlights. Errata sheets for other statements regarding
population trend were not issued:

"At all landscape scales, bear density declined as road densities and traffic volume increased . . . bears tolerated low levels of disturbance, but their vulnerability to humans increased. Thus management efforts should focus on minimizing road density and road-use, and protecting seasonally preferred habitats. . . the negative effects of cutting units were related more to open roads than to reduction of habitat to earlier seres." (p. 120)

"The local population of grizzly bears was tenuously [as noted in the page 112 errata, the population was probably decreasing]during the period of study. Our estimated annual mortality rate was higher than most other brown bear populations in North America. . . The population under study, though skewed towards females, was experiencing the probable maximum sustainable mortality rate, beyond which a decline would be certain," (p.120)

"[The] Swan Mountains study area was approximately 9% private land and man-caused mortality was approximately 7 times higher in the rural portion of the study area (predominantly private land) than in the core (public land). . . strict road access programs on national forest lands will not be sufficient to significantly improve the population trajectory if mortality and habituation of bears on private lands is not reduced. Until effective management programs are developed for private lands, federal lands should be considered invaluable source areas and managed to reduce man-caused mortality. This would be accomplished by establishing high-security core areas that include seasonal habitats and where vehicle access is restricted. . . Approximately 60% of core areas having superior seasonal habitat should be at least 0.5 km from the nearest road." (p. 121)

"The 2 biggest sources of human caused mortality were mistaken identification during the spring black bear season and management removal. . . Our data suggests that the study area black bear population is over-harvested." (p. 121)

If you would like further information please contact Dr. Lee Metzgar, and
The Alliance for the Wildrockies, (406) 721-5420.
The paper is :
Metzgar, L. H. 1998. A Review Of: Rationale and choices made in the
review and development of an access direction proposal for the NCDE grizzly bear
ecosystem. Dated: 10/8/98. Available from The Alliance For The Wild Rockies,
P.O.Box 8731, Missoula MT 59807.