April 24, 2000 Letter from Dr. Larry Irwin to DR. Chris Servheen in reference to the FEIS [Final Environmental Impact Statement ]
Dr. Christopher Servheen
U.S. Fish and Wildlife Service
P.O. Box 5127
Missoula, MT 59806
I wish to comment on the Final Environmental Impact Statement (FEIS) on Grizzly Bear Recovery in the Bitterroot Ecosystem (BE). I previously expressed my personal biological concerns that the BE may not contain sufficient high quality habitat to support a viable population of Grizzly Bears in the future, without supplemental support from adjacent districts.
In my estimation, the FEIS could have done more to assess the condition or quality of the environment and to project future conditions, using existing information. To be sure, the FEIS acknowledged that important sources of energy and protein in the form of anadromous fish and whitebark pine nuts have declined precipitously, but noted that vegetation types comparable to other areas occupied by grizzlies are present, and over 60% of known herbaceous food items and over 80% of known fruit and nut forage items consumed by grizzlies elsewhere occur in the BE.
While knowing that food items and vegetation types are physically present is indeed comforting, the FEIS provided little compelling information that the vegetation types are productive or that the quality of the food supply is sufficiently high now and will be so into the future to support adequate growth of a Grizzly Bear population.
For example, elk population productivity and numbers have declined much more steeply than indicated in the FEIS. In fact, there is high concern among other agencies for declining elk populations in all areas in Idaho north of the Salmon River. While some people believe that elk are declining due in part to black bear predation, the more pervasive, while subtle, factor probably involves forest regrowth following the large forest fires of 1910, 1919, 1931, and 1934.
Those fires created extensive seral brushfields that formerly produced extensive forage for both elk and black bears, and might still provide sources of food for a reintroduced Grizzly population.
However, those brushfields have largely been overtaken by coniferous trees, especially in the northern half of the BE. Moreover, elk may have actually exacerbated the decline of shrubs, including important berry-producing shrubs (such as mountain ash, chokecherry, pin cherry, currants, elderberry, serviceberry, and perhaps even snowberry), via selective herbivory, as described by Riggs et al. (2000).
If so, important succulent food plants that might otherwise be utilized by Grizzlies may also have been reduced in abundance and productivity by elk.
While known Grizzly foods may well be present or even locally abundant, the FEIS would have done well to provide information on the trends in abundance and productivity of those sources of food supplies. Toward that end, I was surprised that the FEIS did not apply what may be substantial information on the BE that was collected by the Interior Columbia Basin Ecosystem Management Project, operating from Walla Walla, Washington and Boise, Idaho.
My understanding was that parts of the BE were studied in detail by that Project and GIS maps are available. Also, future trends in conifers and understory shrubs can be projected using models available from the U.S. Forest Service Research Station in Moscow, Idaho.
In fact, it would have been interesting to apply Dr. Mark Boyce's resource selection model to conditions that can be predicted 50 and 100 years into the future. Incidentally, that form of modeling could have been used to predict specific locales in the BE with the highest current and future likelihood of occupancy by Grizzlies, similar to a topographic map.
I respectfully suggest that doing so would be of high interest.
A related factor affecting the environmental quality for both Grizzly Bears and elk is the invasion of the BE by noxious weeds, not the least of which is spotted knapweed.
It was surprising that the FEIS did not mention the extent or effects of invasion by weeds, nor did it discuss the likely future increases in weeds, which seem certain to further excacerbate the current forage trends.
This may be particularly true for Spring ranges, especially those at lower elevations and those in the southern parts of the BE.
The FEIS noted correctly that vegetation types that commonly support huckleberry plants are well-distributed in the northern part of the BE.
In my own published research on shrub production in those parts of the BE (Irwin and Peek 1979), I observed evidence that the ubiquitous presence of huckleberry plants does not necessarily indicate consistent and abundant crops of berries, particularly under dense coniferous forests.
One wonders how the forest re-growth has influenced the frequency and quantity of huckleberry crops in the BE, and what the trends will be into the future.
Another topic that could have an important influence in that regard may be global warming. Scientists at the University of Montana have discovered that annual temperatures have increased a full 40 F since 1950.
One would expect that the increased temperatures and associated increased frequency of drought could have an impact on production of huckleberries and subsequent reproductive success of bears. If so, the FEIS might have done well to portray the future conditions of those potential sources of food for Grizzlies and other wildlife.
Thus, while there indeed appear to be potential sources of foods for Grizzlies in some parts of the BE, in my opinion the FEIS too swiftly dismissed the issue by stating that the reduced supplies of anadromous fish, whitebark pine nuts and berry-producing shrubs, will simply result in lower densities of Grizzly Bears. It would have been more satisfying if the FEIS would have discussed the cumulative effects of current and future declines in Grizzly food resources that may be critical to post-hibernation (winter sleep), reproductive success, pre-hibernation health and longterm population survival.
As a result, substantial biological uncertainty surrounds the potential reintroduction of Grizzly Bears and whether a self-sustaining population would eventually be established.
Sincerely, Larry L. Irwin, Principal Scientist
Literature Cited Irwin, L.L. and J.M. Peek. 1979. Shrub production and biomass trends in the cedar-hemlock zone of northern Idaho. Forest Science 25(3):415-426.Riggs, R.A., A.R. Tiedemann, J.G. Cook, T.M. Ballard, P.J. Edgerton, M. Vavra, W.C. Krueger, F.C. Hall, L. Bryant, L.L. Irwin and T. DelCurto. 2000. Modification of mixed conifer forests by ruminant herbivores. USDA For. Serv. Gen. Tech. Rep. PNW-GTR (In Press).- page ¶2§ -ncasi National Council for Air and Stream Improvement, Inc.P.O.Box 68, Stevensville, MT59870Phone (406) 777-7215 Fax (406)777-7213 Larry L. Irwin Principal Scientist W. Wildlife Program