United States
Department of
Agriculture
Forest
Service
Tongass National Forest
Forest Plan Interdisciplinary Team
8465 Old Dairy Road
Juneau, Alaska 99801
(907) 586-8700
Reply To:
RG-G-l0-b
Subject:
Brown Bear Viability Assessment Panel Summary
To:
TLMP Revision Planning File
From:
Chris Iverson, TLMP IDT
Date: February 2, 1996
I. BACKGROUND
A panel of brown bear experts met in Juneau, Alaska on January 23-24, 1996 to evaluate the
relative likelihood that TLMP Revision alternatives would maintain persistent and well distributed
brown bear populations throughout their historic range on the Tongass National Forest. Panel
members integrated technical information presented on brown bear ecology in Southeast
Alaska and their personnel experience and knowledge of brown bear ecology with details
concerning design elements of forest plan alternatives. They developed professional judgments
about likely outcomes related to the longterm persistence and distribution of brown bears on the
Tongass National Forest.
The following information was provided to brown bear panelists to conduct this assessment:
l
Overview video of forest planning: Bruce Rene’, TLMP.
l
Overview presentation and discussion of alternatives; Chris Iverson, TLMP.
l Panel assessment procedures; Terry Shaw, TLMP.
l
Presentation on brown bear ecology and habitat relationships in Southeast Alaska: Kim
Titus, Research Biologist, Alaska Department of Fish and Game.
l
Presentation of principle findings of the fish assessment panel: Ron Dunlap, TLMP
l
Copies of:
Extinction Rates in Archipelagos: Implications for Populations in Fragmented Habitats.
Tongass Land Management Plan Framework for Development of Draft Alternatives;
Resource Assessment Panel Meetings, November 7-8 and 15-16, 1995,
January 23-24 , 1996
TLMP Panel Assessment Procedures.
Forestwide Standard and Guidelines: Wildlife (Brown Bear); Riparian.
l
Tongass maps illustrating 9 alternatives and land use allocations; 1954 and 1995
productive old growth forest on the Tongass NF; present old growth abundance and
distribution by alternative; anticipated old growth and seral forest abundance and
distribution in 2095 for all alternatives; productive old growth blocks remaining in 2095 by
alternative; current road existing across the Tongass; planned road system tor Prince of
Wales Island at full implementation of Alternative 9 (current plan) to illustrate potential
longterm transportation system; percent of productive old growth harvested between 1954
to 1995 by Value Comparison Unit (VCU) by; anticipated percent of productive old growth
harvested by VCU in 2095 for all alternatives.
l
Planned acres of productive old growth harvested by alternative by 2095.
l
Planned miles of road construction by 2095 for each alternative.
l
Riparian buffer widths for each of the 3 Ripanan Management Options for the Moderate
Gradient Mixed Control and Floodplain Process Groups.
This summary provides an analysis of factors that emerged as major concepts considered and
debated by panelists that influenced their likelihood outcome ratings. An analysis and
comparison of ratings among alternatives is also presented. Panelists were instructed to base
likelihood outcomes on the anticipated effect that implementation of each alternative would have
in 100 years on the remaining abundance and distribution of habitats to support well distributed
and persistent brown bear populations.
A complete set of notes was taken during the 2-day session, including ail processes and
rating procedures and panelists’ likelihood outcome ratings. These notes are available in the
TLMP planning record and are not repeated here except for important factors affecting
likelihood outcomes.
II. IMPORTANT ECOLOGICAL CONSIDERATIONS
Riparian Habitat Manaaement
Riparian habitat emerged as one of the most important elements associated with brown bear
ecology addressed by panelists. Two components of riparian habitat management were of
particular interest. The first is the relationship between riparian habitat management and the
maintenance of habitat capability to sustain anadromous fish production (see Fish/Riparian Panel
Summary). Salmon obtained from mid-summer to early fall represent a very important food
source for accumulation of energy reserves to sustain overwinter denning for a substantial
proportion of the brown bear population in most years. Panelists agreed that any factor that
diminished net fish production and longterm habitat capability related to variation in riparian
habitat management standards was directly related to their assessment of iongterm brown bear
persistence. Panelists repeatedly requested empirical results of the fish assessment panel to
assist in their assessment task. To maintain independence amongst panel ratings, fish panel
scores were not provided, but a an overview of principal findings from the fish assessment panel
was provided. Thus panelists favored features that reduced management risk to the fishery
resource and maximized riparian habitat protection.
The second component of the riparian habitat is vegetative cover provided by riparian habitats.
Cover for visual obscurity is important for minimizing interaction among bears and between
humans and bears. In addition, unpublished data from local studies revealed that bears also use
daybed loafing sites within the riparian zone where salmon are taken to consume to avoid
interaction with other bears. These sites are generally within 500 feet from the stream. Panelists
were advised by the resource specialist that in his brown bear chapter in the interagency Viable
Population Committee Conservation Strategy (V-POP), he recommended maintenance of a
minimum 300 foot riparian buffer to meet this cover objective.
Panelists also examined the proposed TLMP brown bear standard and guideline that establishes
an objective to provide visual cover along streams important for brown bear foraging without
providing specific distances. This generic guideline was considered inadequate. They
reassessed the riparian buffer widths provided in the 3 riparian habitat management options.
Even the largest buffers of over 250 feet provided in option 1 on Moderate Gradient/Mixed Control
channel types was considered insufficient to meet riparian cover objectives for brown bears. After
extensive discussion, panelists strongly recommended that a minimum 500’ no harvest riparian
buffer be maintained along streams considered important for brown bear foraging. This should be
the default management prescription unless local site inspection for project level analysis revealed
that specific areas were not considered important for brown bear foraging.
Road and Access Manaaement
Roads and human access and the effect on brown bear populations was an equally important
issue debated by panelists. The panel specifically clarified that the issue was the human access
and use of roads and not necessarily the physical nature of the road itself. However, to the
2
extent that road construction and presence also contributed to reduced habitat capability for
anadromous fish populations, a major concern revealed by the fish panel, the panelists’ overall
concern over roads was heightened.
Data was presented that revealed a correlation between miles of road that facilitated human
access and bear mortality on northeast Chichagof Island. Mortality was from legal harvest, illegal
kills, and Defense of Life and Property (DLP). Panelists generally recommended that first priority
would be to retain currently unroaded watersheds in a roadless condition. Secondarily, when
roads must be constructed they should remain in excess of 500 feet from the stream and only
cross perpendicular to the stream. All roads in high priority watersheds should be closed to
establish roadless refugia for bears. No maximum road density thresholds were specifically
recommended by panelists to control the access/bear mortality issue. Of interest, panelists
concluded that moderate timber harvest without construction of additional roads would have
minimal effect (see Upland Old Growth below).
Access management and human education were discussed. The Greens Creek Mine brown bear
management program was featured as a nearterm success in permitting human development and
managing bear mortality Conversely, past evidence pointed to the inability or unwillingness by
the Forest Service to consider road closure and access management, especially on northeast
Chichagof. Rather, a case was cited where the Forest Service was conducting a NEPA analysis
to retain some roads open that were planned for closure in a recently approved timber sale
environmental analysis. The likely abandonment of brown bears from once inhabited landscapes
along the Juneau road system was also cited as evidence of effects of human access and
presence at a more intensive level. Discussion of the apparent absence of brown bears in this
area where they formerly inhabited was a clear example where a gap in brown bear distribution
had developed. Thus absence of bears from one or more adjacent major watersheds constituted
a gap in distribution.
Of interest was the consideration of major transportation corridors planned between Southeast
Alaska and British Columbia adjacent to major river systems bisecting the coastal mountain
range. The Stikine, Unuk, Bradfield, and Taku, rivers were specifically mentioned. This access
would likely result in increased frequency of human/bear interactions with predictable resulting
bear mortality. Bears inhabiting the mainland existed in relatively low densities and natural gaps
in distribution between these major river systems likely already existed. Planned roading and the
resultant human access and associated bear would further place these low density and isolated
bear populations in further jeopardy.
Upland Old Growth.
The upland old growth component of the landscape was a relatively minor factor discussed by
panelists. By definition, this focus excluded the riparian zone and was independent of the road
issue. In essence, while upland old growth forest contributed elements important to bear ecology,
e.g. especially berry crops, forest structure was much less important to panelists. In fact,
panelists estimated that nearly 80% of their overall concerns about longterm brown bear
persistence and distribution was included in the riparian habitat and access/human management
issues. Thus, design features of alternatives relative to harvest techniques, harvest thresholds,
rotation lengths, unevenaged management and other factors affecting upland old growth forest
structure were of secondary importance in panel deliberations. However, factors that resulted
increased road construction and repeated human entries into a watershed were viewed as
adverse to brown bear populations, especially the concept to dispersed extended rotation timber
harvests.
Panelists favored the reserve concept in alternative design, not necessarily as a large block of
unfragmented old growth, but rather as landscapes providing roadless refugia from human
disturbance. Most panelists considered the large 40,000 acre reserves as generally adequate in
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relation to the smaller home ranges of brown bears in Southeast Alaska, though one panelist
judged them too small. Medium reserves were considered too small to independently sustain
brown bear and rather functioned as landscape linkages between large reserves. They also
concluded that the 20 miles may be too far to ensure demographic interchange among bears
between reserves. Twenty miles was considered beyond the average dispersal movement from
telemetry data presented. However, several examples of large movements documented on
Admiralty Island demonstrated at least the capability of bears to move significant distances.
The panel considered current population trends and concluded that there is no evidence of short
or longterm brown bear populations declines in Southeast Alaska. Current morality rates are
estimated at 4% from all sources. The population is apparently reproducing at a rate matching
current mortality and thus maintaining at least a stable population. However, panelists’ ratings
suggest that anticipated cumulative effects of planned management may result in reduced brown
bear habitat capability, reductions in populations size with the resulting creation of more gaps in
distribution or some populations would exist in isolated refugia. Implicit in this conclusion is that
even if all regulated and permitted harvest would cease, morality rates would exceed 4% from
both illegal and DLP sources due to anticipated increases in roading and human population,
resulting in at least locally declining populations.
Subpopulations
Based upon work conducted by Dr. Shields at the University of Alaska, genetically distinct and
relatively isolated subpopulations of brown bears exist in Southeast Alaska. Bears on Chichagof
and Baranof are different from Admiralty and these bears are distinct from the mainland bears that
are more similar to interior British Columbia bears. Further, brown bears in Southeast Alaska are
more closely related to polar bears than brown bears in other regions of Alaska. Variations in
gross morphology and pelage coloration among island bear populations are consistent with
genetic differentiation patterns. Differentiation suggests limited dispersal and interchange among
populations. Based upon this information, panelists were presented the opportunity to assess 100
year likelihood outcomes for individual populations and they accepted this opportunity.
III. COMPARISON OF ALTERNATIVES
Forestwide Ratings
Panelists unanimously agreed that brown bears would not likely be extirpated in 100 years from
the Tongass National Forest under any alternative. All panelists rated Outcome V as 0 for all
alternatives. Wilderness and Legislated LUD IIs essentially guaranteed that brown bears would
persist somewhere in Southeast Alaska in 100 years.
Alternative 1 was rated highest in total likelihood of maintaining brown bears in their current
distribution, combined scores of Outcomes I and II of 93, even though certain populations would
experience some reduction in overall density (a 53 score for Outcome II). The likelihood rating of
7 for creation of temporary gaps or limitation in interaction are likely due to the extent of past
roading and an anticipated future growth in human use of existing roads, in spite of little or no
additional timber harvest.
Due to the planned extensive timber harvest and associated road construction to access the
timber, Alternatives 7 and 9 had the highest likelihoods of limiting distribution of brown bears such
that they might exist in isolated refugia with Outcome IV scores of 40 and 41, respectively.
Panelists generally agreed that either Outcomes III, IV or V would not represent well distributed
populations based upon the assessment criteria they were provided. Alternatives 2, 7, 8, and 9 all
had combined scores of over 50 for this cumulative outcome of III, IV, and V combined. All of
these alternatives have in common relatively extensive planned timber harvest and all are
managed with a 100 year rotation. Interestingly, while panelists conceptually liked the reserve
4
concept that establishes roadless refugia and is a forestwide feature of Alternative 8, this
alternative had a combined score of 71, higher even than alternative 2 (combined score of 61).
The result suggests that reserves did not compensate for the extensive timber harvest and
roading that would likely exist between reserves. Together, these 4 alternatives present the
greatest longterm risk to maintenance of well distributed brown bear populations in 100 years.
Surprisingly, Alternative 3 ratings did not reflect the panelists’ discussion conclusion that riparian
habitat protection was a significant feature in brown bear management. Alternative 3 is the only
alternative with riparian option 1 that has the widest riparian buffers on most all channel types. In
spite of these substantial buffers in high quality fish watersheds, Alternative 3 was rated close to
alternatives 4, 5, and 6 in cumulative Outcome I and II scores of 60, 55, 66, and 51, respectively.
Perhaps, as the panelists generally concluded, even riparian option 1 buffers were not adequate.
In addition, the extended rotations in alternatives 4 and 5 inferred greater dispersion of future
timber harvest into roadless watersheds and were rated similar to alternatives 3 and 6 in spite of
much less total planned harvest of old growth. Nonetheless, these four alternatives had a
moderate likelihood of maintaining brown bear populations at least in their current distribution in
spite of the potential for development of temporary gaps in distribution.
Mainland Population
Panelists generally had greater concerns for the mainland bear populations than the other 2
populations rated. The mainland population was rated consistently lower than Chichagof/Baranof
for all alternatives in combined Outcomes I and II. In fact only Alternative 1 provided better than
an even likelihood of maintaining a well distributed population 100 years (Table 2). These ratings
support discussion that focused significant concern on the low density population that may already
exist in relatively isolated regions. Anticipated future roading and human access development
would exacerbate this natural situation and place these populations at additional risk.
Chichagof/Baranof Population
Four alternatives (1, 3, 4, and 5) had combined outcome I and II scores over 50 suggesting a
reasonable likelihood that persistent and well distributed populations would exist on
Chichago/Baranof Islands in 100 years. Alternatives 2, 7, 8, and 9 could result in at least the
development of permanent gaps in brown bear distribution (Table 3).
Admiralty Island Population
Panelists believed brown bears had a very high likelihood of maintaining persistent and well
distributed populations on Admiralty Island due to its Wilderness designation that would preclude
development considered adverse to brown bears. Ratings for all alternatives were above 97 for
Outcomes I and II (Table 4).