Benn, Bryon and Stephen Herrero. 2000. Grizzly Bear Mortality and Human
Access in Banff and Yoho National Parks, 1971-98.
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GRIZZLY BEAR MORTALITY AND HUMAN ACCESS IN BANFF AND YOHO NATIONAL
PARKS, 1971-98
Bryon Benn
and Stephen Herrero
Abstract: We conducted
spatial and temporal analyses to examine the relationship between
access, changing grizzly bear management strategies and grizzly bear
mortality for the period 1971-98 in Banff and Yoho National Parks,
Canada. We summarized mortality rates by cause of death, sex, age, and
cohort. The annual number of grizzly bear deaths declined significantly
from 1971-1984 to 1985-98. However, the female portion of this mortality
was 80% from 1985-98. Total human-caused mortality rates for the 2 parks
combined were estimated at 7-9% for the 1971-84 analysis period. These
estimated rates dropped to below 2% during 1985-98. Human-related causes
were the primary sources of recorded grizzly bear mortality in the study
area (119 of 131 known mortalities). Problem wildlife control accounted
for 71% of 119 known human-caused mortalities, followed by highway and
railway mortalities (19%), unknown cause of death (9%), and research
(<1%). One hundred percent of 96 human-caused mortalities with known
accurate locations fell within 500m of roads and 200m of trails (25% of
the area of suitable habitat in the study area). Eighty percent of 96
mortalities occurred below 2000m. Area-concentrated kills occurred at
Banff townsite, Lake Louise, and along the Trans Canada Highway.
Management of development, trail access and human food and garbage are
critical for managing grizzly bear mortality in the national parks. We
present specific recommendations.
Introduction
Grizzly bears
in Banff and Yoho National Parks are part of a regional ecosystem called
the Central Rockies Ecosystem (Figure 1). The Central Rockies Ecosystem
is experiencing intensive exploration and development of coal, oil and
gas, cattle production, timber harvesting, housing and highway
development, and outdoor recreation. Moreover, present attitudes towards
the grizzly bear, a potentially dangerous animal (Herrero 1985) and
competitor for food and space (Mattson 1990), challenge human - grizzly
bear coexistence. As a result, the grizzly bear is suffering from
continuing habitat degradation and potentially unsustainable mortality
rates in some regions of the Central Rockies Ecosystem (Herrero et al.
2000).
The national park portions of the Central Rockies Ecosystem
continue to experience increases in human use, commercial development
and major transportation expansion with ongoing twinning of the Trans
Canada Highway through Banff National Park (Banff-Bow Valley Study
1996). The grizzly bear population estimate for Banff National Park
ranges from 55-85 (Vroom 1974, Gibeau et al. 1996). Interagency planning
for effective land use at the regional scale (Herrero 1995), whereby
bears can meet their energetic requirements, and encounters between
humans and bears can be reduced, may be the best option for reducing
grizzly bear mortality (Mattson and Knight 1991).
Natural survival rates for adult grizzly bears in unhunted
populations are high and consistent (Knight and Eberhardt 1985, McLellan
1989), whereas young bears die more frequently of natural causes such as
intraspecific aggression (Stringham 1983), accidents (Nagy et al. 1983),
and nutrition related causes (Nagy et al. 1983, Knight et al. 1988). In
the southern parts of grizzly bear range, natural mortality is
infrequently discovered, and is probably a minor cause of adult
mortality (McLellan et al. 1999). Mortality data from around North
America show that human-caused mortality far outnumbers natural
mortality (Craighead et al. 1988, Carr 1989, McLellan 1989, Dood and Pac
1993, Gunson 1995, Gibeau et al. 1996). Historical (Storer and Tevis
1955, Noble 1972, Nielsen 1975, Young and Beyers 1980, McCrory and
Herrero 1982, Brown 1985) and recent works (McLellan and Shackleton
1988, Mattson et al. 1996, Gibeau et al. 1996, Benn 1998, McLellan et
al. 1999) consistently link the type and degree of human land use with
grizzly bear mortality.
Percentage values for sustainable total and harvest mortality
rates have been identified in computer simulated populations (Bunnell
and Tait 1980, Harris 1984, Harris 1986). However, no clear
understanding exists of the relative risk of mortality posed to bears by
human activities other than hunting. Determination of population numbers
and vital rates for grizzly bears require long term study, and the
number of undetected mortalities are typically estimated by inference.
However, McLellan et al. (1999) used unreported mortality of
radio-collared bears from various western cordilleran studies to
estimate the percentage of unreported human-caused mortality. Due to the
difficulty in reliably determining all relevant variables, the threshold
where grizzly bear populations begin to decline can rarely be determined
precisely.
Roads are frequently implicated as contributing to increased
grizzly bear mortality, as they facilitate access for a host of human
activities, increase the frequency of energetically costly flight
responses, and increase vehicle related mortalities (Mattson et al.
1987, McLellan and Shackleton 1988, McLellan 1989, Nagy et al. 1989,
BCMOELP 1995, Gibeau et al. 1996). As well, roadside vegetation may
attract bears to roads compounding the risk. At some scale, grizzlies,
in particular established adult females, will cease crossing major
transportation corridors (Gibeau and Herrero 1998a).
We analysed grizzly bear mortality for Banff and Yoho National
Parks for the period 1971-98. Results are discussed temporally with
respect to changing grizzly bear management strategies, and spatially to
examine the effects of access on mortality in the grizzly bear
population.
Study Area
The study
area is defined politically by the outermost boundaries of Banff and
Yoho National Parks (Figure 1). Banff National Park is 6,836 km2 and Yoho National Park is 1,313 km2. A description of the
vegetation and climate for the entire Central Rockies Ecosystem is
provided in Benn (1998). Both national parks are dissected by major
transportation corridors. Approximately 42% of the area of these parks
is rock and ice. Thus, grizzly bear habitat is restricted to major
vegetated valley systems. Human use is also concentrated in major valley
systems.
Figure
1. Study area map. The
National Parks of the Central Rockies Ecosystem (Benn 1998).
Methods
Grizzly bear
mortality databases and immobilization (translocation) databases were
supplied by Banff and Yoho National Parks for the period 1971-98.
Additional mortality records came from other wildlife files provided by
Parks Canada Western Region Office, annual warden and superintendent
reports, a consultant’s report (Millson 1978), and several graduate
theses (Noble 1972, Taylor 1984). Mortalities include dead bears, and
bears translocated so far that they are considered unable to interact
with the population of the removal area.
Mortality Summaries
We used all
mortality data to summarize mortality by cause of death, sex, age, and
cohort. To estimate mortality rates, we used population estimates of 60
and 80 (Gibeau et al. 1996) for Banff National Park and 20 for Yoho
National Park (Benn 1998). These were based on the subjective
assessments of knowledgeable field personnel. The following equation was
used to estimate mortality rates:
• estimated mortality rate = number of mortalities/period in
years/population estimate
Spatial Analyses
National park
access information came from 1:50,000 digital National Topographic
Series data supplied by Parks Canada. Mortality locations were
referenced to the UTM grid to the nearest 100m, with a location
descriptor such as a river, creek, or cultural feature added. Interviews
were conducted with past and present wardens and wildlife managers to
collect additional information about specific mortalities and their
locations. Accurate locations were those described by UTM grid reference
(+100m) and matching geographic descriptor. Reasonable locations
were described as being within some stated distance from a known road,
trail, drainage or development. Estimated and unknown locations
contained a vague or no description of the kill site respectively, and
were not used in the spatial analyses.
The access and mortality data were entered into a geographic
information system, MapInfo 4.0 (MapInfo Corporation, Troy, New York).
Zones of influence (ZOI) of 500m and 200m were set around roads and
trails respectively. The road layer included railway lines and all roads
open to the public and negotiable by 2 wheel drive vehicle. The trail
layer included roads closed to the public, utility corridors, and any
other linear access features accessible by hiking, mountain biking, or
horseback. For zone of influence area calculations, road and trail
buffers were combined into a single coverage. The area of overlap was
only calculated once, and mortality locations in the area of overlap
were analysed as occurring within road buffers, as roads were assumed to
have a greater effect on mortality risk than trails. These data were
used to test the following hypothesis:
• Ho1: The distribution of mortalities on the landscape
did not differ from a random distribution.
The number of
random points expected within the buffer zones was created by
multiplying the total number of mortalities by the proportion of the
area of suitable habitat covered by buffers. Suitable habitat is land
below 2400m. Above this, there is little grizzly bear foraging (Gibeau
and Herrero 1998b). We tested the distribution of mortality locations
against a random distribution of points at the 0.05 level of
significance, with a single-classification Goodness of Fit Test (G-test
with William’s Correction Factor), using the random points inside and
outside of zones of influence as expected values.
We tested mortality locations for sensitivity to minor
inaccuracies by systematically perturbing all points by 300m in each of
the four cardinal compass directions. We then retested hypothesis 1 with
the four new values.
Mortalities were tallied with respect to proximity to townsites
and commercial tourist operations. Analysis of these features considered
the presence or absence of food attractants (Weaver et al. 1986; Mattson
et al. 1987).
We compared the elevation of 95 human-caused grizzly bear
mortality locations with a series of elevations taken at geographic
landmarks along the Bow and Kicking Horse River valleys, and with the
elevations of some popular tourist destinations and park developments.
Temporal Analyses
To relate
changes in mortality characteristics with changing patterns of human use
and evolving management concerns and actions, we stratified the
mortality data into 2 periods. We chose 1984-1985 as the break, although
no major changes occurred in any single year. Rather a series of events
in the early 1980s led to a progressive modification in management
practices. These actions included 1) the 1980 Whiskey Creek bear
maulings in Banff National Park (Westhaver and Williams 1980, Herrero
1985), which stimulated increased efforts at communication and public
education with respect to bears and improved garbage management, 2)
closure of the Banff landfill in 1981, and 3) commencement of fencing of
the Trans Canada Highway from the east park gate in 1983. Also, we
recognized that it would take a few years for the bear population to
adapt behaviorally to events such as the landfill closure. Finally, for
ease of comparison, these 2 periods are of equal length. The
non-parametric pairwise Mann-Whitney U-test was used to test for
differences in frequencies between periods. All tests were run at the
0.05 level of significance. The following hypotheses were tested:
• Ho2: The annual number of grizzly bear mortalities in
Banff and Yoho National Parks did not differ significantly between the
periods, 1971-84 and 1985-98.
• Ho3: The annual number of problem wildlife grizzly
bear mortalities in Banff and Yoho National Parks did not differ
significantly between the periods, 1971-84 and 1985-98.
Finally, we analysed all dated mortalities by cause of death and
by grizzly bear seasons (April-July = pre-berry, July-Oct = berry,
Oct-Dec = post-berry).
Results
There were
131 grizzly bear mortality records in Banff and Yoho National Parks, of
which 12 were natural deaths, all in Banff National Park. We used the
remaining 108 records from Banff National Park and 11 from Yoho National
Park to summarize human-caused grizzly bear mortality.
Mortality Summaries
Average
annual mortality was 4.3 grizzly bears/year, with peaks of 15 recorded
deaths in 1972 and 13 in 1980 (Figure 2). The human-caused mortality
rate from 1971-98 was estimated to be 5.3% or 4.3% using the combined
population estimates of 80 or 100 for Banff and Yoho National Parks
respectively.
Figure
2. Annual number of
human-caused grizzly bear mortalities by type for Banff and Yoho
National Parks, 1971-98 (n=119). PW=problem wildlife,
H/RR=highway/railway, Other=research or unknown (Benn 1998).
Problem wildlife control actions (n=85) and highway and railway
mortalities (n=22) accounted for 71% and 19% of the 119 human-caused
grizzly bear deaths recorded. The remaining 10% (n=12) included 1
research related incident and 11 deaths of unknown cause. In addition to
mortalities recorded within Banff and Yoho National Parks, at least
seven research grizzlies known to use Banff and Yoho National Parks were
killed in British Columbia and Alberta (Gibeau and Herrero 1998c). The
breakdown of mortalities by sex, age, and cohort is presented in Table
1.
Table 1. Percent grizzly bear mortality by sex, age, and cohort for Banff
and Yoho National Parks, 1971-98 (n=119). The number of records is in
parentheses (Benn 1998).
Sex |
male 33.9 (40) |
female 33.9 (40) |
unknown 32.2 (39) |
Age |
adult 34.7 (41) |
dependent 29.7 (35) |
subadult 12.7 (16) |
|
unknown 22.9 (27)
|
|
|
Cohort |
dependent 29.4 (35) |
ad.female 16.0 (19) |
ad.male 15.1 (18) |
|
sub.female 7.6 (9)
|
sub.male 1.7 (2)
|
unknown 30.3 (36)
|
Of all human-caused grizzly bear mortalities where the cohort
was known, adult females and dependent young accounted for 65% (54 of
83). Females accounted for 50% of all mortalities of known sex since
1971, and even after closure of the Banff landfill in 1981, 83% (18
of 23) of bear mortalities of known sex were female. An additional 11
mortalities were unclassified as to sex during this time. Figure 3 shows
the percentage of females in the annual mortality.
Of 85 problem wildlife mortalities, 64.7% (55) were destroyed
and 35.3% (30) were handled for translocation purposes. Thirteen of
the grizzlies handled died accidently, and 15 were translocated. Five
of the translocated bears were placed in the Calgary Zoo and 5 are known
to have died in Alberta within 1-2 years of capture (1 shot legally,
2 shot illegally, 1 problem wildlife, 1 unknown fate).
Eleven family groups consisting of at least 6 cubs of the year
and 10 yearlings were destroyed or translocated out of the ecosystem.
This was considered a minimum number as 69% of 64 recorded problem wildlife
mortalities were adult females (n=17) and bears of dependent age (n=27),
and 21 records had no sex or age attached. Of 15 highway and railway
mortalities where the cohort was known, adult males accounted for 47%
(n=7), dependent bears 33% (n=5), and adult and subadult females 20%
(n=3).
Figure
3. Percentage of females in the annual grizzly bear mortality. Numbers
above the bars are the total number of mortalities with sex known for
that year.
Spatial Analyses
Approximately
58% (4,726 of 8,149 km2) of the study area is suitable grizzly
bear habitat. Zones of influence occupy about 25% of this area of suitable
habitat (Gibeau and Herrero 1998b). One hundred percent of 95 human-caused
grizzly bear mortalities, classified as having accurate or reasonable
locations, occurred within zones of influence along roads and trails,
and around human settlements (Figure 4). Many of the points around Banff
and Lake Louise represent >1 mortality. The null hypothesis (Ho1)
with respect to a random distribution of mortality locations was rejected
(G=391.046, df=1, P=0). Perturbations of the data did not alter the
results of Ho1 [ i) G=265.578, df=1, P=0; ii) G=353.007, df=1, P=0; iii) G=323.437, df=1, P=0; iv) G=288.971, df=1, P=0]. Area-concentrated mortality occurred
at Banff and Lake Louise townsites, and along the Trans Canada Highway
(Table 2).
Figure
4. Map of grizzly bear
mortality locations in relation to roads and trails in the National
Parks study area, 1971-96 (Benn 1998).
Table 2. Types
of developments and land uses where human-caused grizzly bear mortalities
occurred in Banff and Yoho National Parks, 1971-98 (n=95) * (Benn 1998).
Location of kill
|
No.
|
Detail of Locations
|
Highway / railway
|
22
|
Trans Canada (16), Banff-Jasper (2), other
(1), railway (3)
|
Townsites
|
27
|
Lake Louise (15), Chateau Lake Louise (7),
Banff (2), Field (3)
|
Garbage dumps / landfills
|
19
|
Banff (15), Lake Louise (4)
|
Campgrounds
|
16
|
|
Ski Resorts
|
8
|
Lake Louise (3), Norquay (3), Sunshine (2)
|
Commercial Lodges
|
11
|
|
Warden cabins
|
3
|
|
* Total number listed is >95, as Highway mortalities at some
townsites are tallied twice.
Eighty percent (n=77) of all known mortality locations were below
1800m (5900 ft). The remaining 20% (n=19) fell between 1800m and 2100m
(6890 ft, Figure 5). Treeline
in the Central Rockies Ecosystem is approximately 2210-2270m (7200-7400
ft).
Figure 5. Frequency
of grizzly bear mortality locations for a range of elevations in Banff
and Yoho National Parks, 1971-96 (n=95) (Benn 1998).
Elevations at some specific locations through
the parks: Banff 1375m (4500 ft), Castle Junction 1430m (4700 ft), Lake
Louise 1540m (5100 ft), Kicking Horse Pass 1650m (5400 ft), Field, BC
1250m (4100 ft). The Chateau Lake Louise 1740m (5700 ft), Skoki Lodge
2135m (7000 ft), Moraine Lake Lodge 1900m (6200 ft), Lake O’Hara 2000m
(6600 ft).
Temporal Analyses
We rejected
Hypotheses 2 and 3 as the annual number of mortalities (total and problem
wildlife) declined significantly into the 1985-98 period [total (n1=99,
n2=20), U=151.0000, P=0.0003; problem wildlife (n1=69,
n2=16), U=136.5, P=0.0034). The estimated mortality rate
declined from 7.1-8.8% during the 1971-84 period to 1.4-1.8% in the
1985-98 period.
Problem wildlife mortality was the greatest cause (85 of 119)
of grizzly bear death in both analysis periods. Although the number
of problem wildlife deaths declined in the 1984-98 period, the percentage
of female (adult and subadult) problem wildlife mortalities increased
from 50% to 80%. Adult females and dependent bears increased from 66%
(33 of 50) of the total mortality in the early period, to 79% (11 of
14) during 1984-98. Only 2 of 22 highway and railway mortalities occurred
in the latter analysis period.
Of 72 dated human-caused grizzly bear mortalities, 57% (n=41)
occurred during the berry season (mid-July-late September) and 35% (n=25)
and 8% (n=6) took place in the pre-berry, and post-berry seasons respectively.
Seventy-five percent (n=36) and 58% (n=28) of 48 dated problem wildlife
mortalities occurred during the peak tourist season (late June – early
September) and during the berry season respectively. Berry season is the time of year when Central Rockies Ecosystem
grizzlies normally feed primarily on buffaloberry (Shepherdia
canadensis) at lower elevation, often along roads and in close proximity
to people.
Discussion and Conclusions
Ecological
integrity is the stated priority of the national parks (Banff National
Park 1997) and the grizzly bear serves as the premier indicator of the
health of the terrestrial ecosystem (Banff-Bow Valley Study 1996, Gibeau
et al. 1996). Managing grizzly bear mortality at a level that prevents
population decline is fundamental. As precise measurements of population
vital rates are not yet available, management of mortality must be conservative
and management plans must consider adjacent jurisdictions in Alberta
and B.C. (Herrero et al. 1998).
The 119 recorded human-caused grizzly bear deaths in Banff and
Yoho National Parks were considered to be the minimum number from 1971-98.
Past and present wardens and wildlife managers suggested that there
were probably more mortalities than were recorded, particularly during
the 1970s (R. Kunelius, retired Park Warden, Banff National Park, Alberta,
personal communication 1997; M.
Gibeau, Principle Researcher,
Eastern Slopes Grizzly Bear Project, University of Calgary, Alberta,
personal communication 1997; D. Poll Wildlife Biologist, Parks Canada,
Calgary Office, Alberta, personal communication 1997). This large number
of human-caused grizzly bear mortalities contrasts strongly with the
adjacent and larger Jasper National Park, where from 1975-98 there were
only 39 known grizzly bear mortalities (13 females, 15 males, 11 unknown,
W. Bradford, Wildlife Warden, Jasper National Park, Jasper, Alberta,
personal communication 1999).
Problem wildlife mortality was the most significant cause of
death throughout the period of this study. Although the number of problem
wildlife deaths declined in the 1984-98 period, the percentage of female
problem wildlife mortalities increased from 50% to 80%. This estimated
human-caused female mortality percentage (82% for the 1984-98 period)
is the highest reported for a 10+ year period for any grizzly bear population.
As well, the human-caused mortality percentage of dependent bears remained
high throughout the study period. These results may be explained by
changing habitat use by specific cohorts over time. The higher estimated
percentage of male mortality in the early period was probably the result
of more male bears feeding closer to people (in landfills and unsanitary
campgrounds, Noble 1972). With the landfill closures and improved camper
attitudes and garbage management, adult males may then have selected
habitats remote from human activity zones. Adult females with young
and subadult grizzlies may then have been more likely to use habitats
near people, presumably to avoid adult males (Mattson et al. 1992, Gibeau
et al. 1996). Thus, they may have been prone to habituation and attraction
to human food and garbage, increasing their mortality risk and potential
for being destroyed or translocated as “problem” animals (Mattson et
al. 1987). This dynamic was previously described for the Yellowstone
Ecosystem (Craighead et al. 1995).
Where grizzly bears are subject to human-caused mortality, there
is still a strong need to manage human food, garbage and access, as
a way of keeping grizzly bears and people spatially separated, especially
in seasonally important grizzly bear habitats. Mattson (1993) states
that human-caused mortality is the primary cause of population declines
and extirpations, and that human access interacting with human values
and attitudes determines the frequency and lethality of bear-human contacts.
We found that grizzly bears died at low elevations and near human
settlements and access routes (95 of 95 accurate and reasonable locations
were within 500m of a road or 200m of a trail). Roads, trails, and developments
are almost always placed in valley bottoms, often fragmenting riparian
habitats. Similarly, area concentrated kills at settlements such as
Banff and Lake Louise Townsites and along roads and trails occurred
throughout the Central Rockies Ecosystem (Benn 1998) and in other grizzly
bear populations (Mattson et al. 1987, McLellan and Shackleton 1989a,
Nagy et al. 1989, Mace et al. 1996). Roads and trails improve access,
and when placed in important seasonal habitats, increase the potential
for negative bear-human encounters (McLellan and Shackleton 1989b).
Increased access to the backcountry has been shown to alter bear behavior
(McCullough 1982, Jope 1985), increase bear-human conflicts (Dalle-Molle
and Van Horn 1989), increase the number of grizzly bear removals (Martinka
1982, Leonard et al. 1990), and displace certain cohorts, such as females
with young (Mattson et al. 1987, Gilbert 1989).
Our estimated human-caused mortality rate of 7.1-8.8% for the
1971-84 analysis period exceeded the suggested 6.5% total human-caused
mortality for sustainability of a grizzly bear population (Harris 1986).
The abrupt decline in grizzly bear mortality into the mid 1980s was
correlated with closing the Banff landfill, improvements to garbage
management, increased public education regarding living and recreating
in bear country, greater tolerance of grizzly bears, fencing of the
Trans Canada Highway, and increased use of aversive conditioning techniques
over removals. However, the high mortality rate of the early period
may have depressed the park’s grizzly bear population. This possible
effect could have continued through the 1984-98 period even with the
lower estimated mortality rate (1.4-1.8%), due to lag effect and mortality
being concentrated in the female cohort. Closures of Yellowstone National
Park landfills were followed by sharp declines in reproductive and survival
rates (Craighead et al. 1974). In Yellowstone, the number of recorded
mortalities almost doubled in the 2 years of major landfill closures,
as bears sought food around other human developments and settlements
(Knight and Eberhardt 1984, Mattson et al. 1992, Craighead et al. 1995).
Human intolerance and inadequate management of access and food
attractants continue to be important contributing factors to grizzly
bear mortality in Banff National Park. Additional concerns are related
to the role of national parks as protected areas, the continuing high
rate of commercial development inside and near the parks, and the associated
decline in the amount of secure habitat available for grizzlies (Gibeau
and Herrero 1998b). These concerns are well-founded given the high female
mortality rate and the large number of family groups that have been
removed from the ecosystem near developments and access routes.
In Banff National Park, specific steps have been taken to reduce
human-caused grizzly bear mortality. Recommendations by the Eastern
Slopes Grizzly Bear Project to the Banff-Bow Valley Task Force (Gibeau
et al. 1996) led to the implementation of an annual human-caused mortality
target of <1% of the estimated grizzly bear population. Also, habitat
effectiveness targets aimed at supporting grizzly bear habitat use have
been set for most carnivore management units. Other actions being taken
or considered are removing or reducing human use from seasonal high
quality grizzly bear habitats, regulating the number of people on certain
trails, trail closures during periods when a given area offers important
feeding opportunities for grizzlies, moving facilities out of important
wildlife movement corridors to afford bears the room to move around
developed areas, and aversive conditioning of roadside habituated bears.
By implementing such measures aimed at reducing potential conflicts
between humans and grizzlies, human-caused grizzly bear mortality and
the potential for human injury can be reduced. There is an urgent need
for these measures to be successful in the national parks and the rest
of the Central Rockies Ecosystem. A recent population and habitat viability
assessment workshop predicted both population and habitat declines for
grizzly bears in the Central Rockies Ecosystem (Herrero et al. 2000).
Grizzly bear management will have come of age in national parks when
almost all adult grizzly bears in the parks die natural, not human-caused
deaths. Because Banff and Yoho National Parks are assumed to serve as
core refugia for sensitive species such as grizzly bears, and because
grizzly bear hunting exists on most of the land surrounding these national
parks, human-caused mortality inside of the parks must be minimal.
Recommendations
The following
recommendations are based on the stated goal of Parks Canada to maintain
a naturally regulated population and distribution of grizzly bears in
the mountain national parks. These recommendations are offered as ways
to prevent future increases in mortality, to reduce the unnecessary
killing of grizzly bears, and to assist in the inter-jurisdictional
management of grizzly bear mortality.
1. During the analysis period, a considerable number of grizzly
bear deaths were thought to not have been recorded in official park
databases, and the records were often missing important data. This has
improved in recent years, but accurate, consistent, and complete reporting
and recording of mortality and translocation data are necessary.
2. There is some variation in the way mortality data are classified
between jurisdictions in the Central Rockies Ecosystem. Park wildlife
managers should work with managers from other jurisdictions to develop
the same coding conventions, and clearly define the different causes
of death.
3. DNA censusing techniques have been used recently to generate
population estimates (Gibeau and Herrero 1998a). Unfortunately, sampling
intensity was not sufficient for acceptable confident limits. We recommend
increasing the level of commitment to population estimation as appropriate
assessment techniques become available.
4. Acquiring accurate mortality locations is necessary for understanding
and managing mortality with respect to access, development and use of
the landscape. Mortality needs to be monitored into the future to understand
the effectiveness of management decisions. Additional information needs
to be collected such as the distance a bear died from an access route
or facility, the type of access route, the condition of the access route
at the time of the mortality, and the mode of travel of the person(s)
responsible for the killing or translocating of the bear. In addition,
detailed notes about the cause of the mortality are required, such as
were any food attractants present, were natural food species present,
and what, if any human behaviors played a role in the mortality.
5. We recommend more commitment to quotas and/or closures of roads
and trails to permit use by grizzlies of seasonally important feeding
sites. Approximately 21% of Yellowstone National Park is seasonally
closed to the public (C. Schwartz. Leader, Yellowstone Grizzly Bear Research, Yellowstone National
Park, Wyoming, personal communication 2000).
6. Area closures should be proactive and not just after an incident.
They should be based on indicators such as habitat quality and known
bear use of an area.
7. Effective legislation and enforcement should be employed with
respect to food and garbage handling. All backcountry users should be
required to store food, garbage, and horse feed in bear-proof metal
or seamless PVC containers, or effectively elevate attractants between
trees, or isolate camp within an effective portable electric fence.
Management of garbage, as well as human and pet foods, continues to
be a problem around Banff, Lake Louise and in some campgrounds. Food-conditioned
grizzly bears present an increased threat to human safety (Herrero 1985),
and usually end up being destroyed or translocated.
8. To understand the effects that new management strategies and
probable increases in human use of grizzly bear habitat have on grizzly
bear mortality and population status, analyses should be repeated and
reassessed in the future with more accurate population estimates.
9. Work with provincial wildlife agencies to set up no hunting
zones around the parks. Many grizzly bears in high use recreational
areas have become accustomed to living close to people. This makes them
vulnerable to people in areas where hunting is permitted when they appear
at close range, even when the bears are acting naturally and non-aggressively.
Such bears frequently die from people’s perceived self-defense and illegal
activities.
10. Increase the use of aversive conditioning programs on roadside
and campground habituated bears. On-site releases and aversive conditioning
of many problem bears would reduce the costs and risks associated with
translocating grizzlies.
11. If translocating problem bears continues to be used as a management
tool, initiate a study using radio-marked translocated bears to look
at the success of such translocations, and the fate of the bears moved.
If certain sites are used for multiple releases, radio-mark a sample
of resident bears to understand the effect these releases might have
on the resident population.
12. Continue informing the public about bear activity in high human
use areas, and educating the public with respect to how to behave in
bear country.
All
of these recommendations will require adequate funding to be carried
out.
Acknowledgements
We
thank Dave Poll, Bill Vroom, Mike Gibeau, Paul Paquet, Ardys Flegel,
Scott Jevons, and many from the Parks Canada Warden Service. We are also
indebted to the Eastern Slopes Grizzly Project Steering Committee and
the Faculty of Environmental Design, University of Calgary for funding
and support. John Nagy, Cliff White, and Mike Gibeau reviewed and
provided constructive comments on the manuscript.
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