Eastern Slopes Grizzly Bear Project

November 1999

Cumulative effects modelling was developed in the 1980’s to quantitatively and qualitatively assess the cumulative effects of human activity on grizzly bear habitat and habitat use in specified areas of grizzly bear range. The Eastern Slopes Grizzly Project is an interagency, multi-stakeholder research project designed to understand and predict the cumulative effects of development on grizzly bears along the eastern slopes of the Rockies including Banff National Park. Results from the Eastern Slopes Grizzly Bear Project will provide concrete answers to questions regarding the impacts of humans on grizzly bears in the Central Canadian Rockies including Banff National Park. However, impending land-use decisions in the Lake Louise area of Banff National Park made that area of special concern to Parks Canada.

Habitat effectiveness (HE) modelling is 1 part of a cumulative effects assessment. HE modelling is a product of overlaying 2 input layers, habitat potential and human disturbance. Habitat potential is the inherent capability of the landscape to support grizzly bears. Grizzly bears respond to human activities by altering their normal spatial and temporal patterns of habitat use. Realized habitat is land that grizzly bears wary of humans will continue to use after the effects of human disturbance on the landscape have been accounted for. HE is the amount of realized habitat expressed as a percentage of the landscape’s potential. HE modelling is applied at a landscape scale; bear management units (BMU’s) typically encompass watersheds.

In 1997, Parks Canada developed a new management plan for Banff National Park in which park planning and operations are driven by the grizzly bear HE targets within BMU’s. Geomar Consulting Ltd. and Parks Canada developed an interative HE model at a 1:50,000 scale to assist with planning and managing human use and development within the national parks. This iterative HE model allows park managers to develop land-use scenarios that will attain grizzly bear HE targets set out in the new management plan. Parks Canada contracted Arc Wildlife Services Ltd. and Riddell Environmental Research Ltd. to develop a refined HE model (1:20,000 scale) for the Lake Louise area to assist with management planning in that area. This work was conducted cooperatively with the East Slopes Grizzly Bear Project with access to their data. The study area encompassed approximately 630 km² of Banff National Park centred on the Village of Lake Louise. Habitat potential and realized habitat were mapped, and HE values were determined for the Skoki, Lake Louise, Baker, and South Pipestone BMU’s.

This report summarizes the results of the HE model for the Lake Louise area, and places those results in the context of cumulative effects assessment and grizzly bear conservation in Banff National Park and the surrounding Central Canadian Rockies Ecosystem.

The landscape in the Lake Louise study area is diverse and its value to grizzly bears is variable. Based on potential habitat modelling, 29% of the study area is made up of areas that have no food value for grizzly bears with values from 17% (South Pipestone BMU) to 40% (Lake Louise BMU) in individual BMU’s. Similarly, the amount of grizzly bear habitat rated as good or very good in the potential habitat model comprised 24% of the study area. Since the sizes of the 4 BMU’s are variable, the amounts of good grizzly bear habitat and unusable terrain varies across the study area. The Baker BMU is both the largest of the 4 BMU’s and the BMU with the most habitat rated as good or very good for grizzly bears, more than twice as much as any other BMU. The Lake Louise BMU is the second largest but also has the most land that is not rated as habitat for grizzly bears.

The spatial and temporal distribution of potential habitat is also important to bears. Grizzly bear habitat in mountain landscapes is naturally fragmented by the distribution of inhospitable terrain at higher elevations. In the Lake Louise study area, large continuous pieces of potential grizzly bear habitat are associated with major valley bottoms, in particular the Bow River, the Pipestone River, Baker Creek, and the upper Red Deer River. Grizzly bear habitat at higher elevations tends to have a patchy distribution relative to the valley bottoms. Temporal variation in potential habitat quality for grizzly bears results from the changing importance of plant foods and other food sources throughout the year. The food habitats model rated habitat polygons for grizzly bears on a monthly basis to take into account this variation. As a result, the relative quality and quantity of habitats rated as good or very good for grizzly bears in the potential habitat model changed with the seasons.

Within the Skoki BMU, the Bow Valley contains the largest contiguous pieces of good and very good grizzly bear habitat in all seasons. The majority of the Skiing Louise lease within the Bow Valley is rated as good or very good potential grizzly bear habitat in all seasons. On an annual basis, good and very good habitats encompass 2,635 ha or 17% of the BMU, while non-habitat accounts for 5,175 ha or 33.2%. The Baker BMU contains more good and very good grizzly bear habitat than any other BMU within the Lake Louise study area. On an annual basis, good and very good habitats account for 6,791 ha (40% of the BMU), while land rated as non-habitat for grizzly bears takes in an additional 4,306 ha (25% of the BMU). The largest contiguous block of good and very good habitat in all seasons includes the Bow Valley and the lower portions of Baker Creek. Twenty-four percent of the South Pipestone BMU or 3,229 ha is rated as good or very good on an annual basis. Non-habitat accounts for 18% or 2,388 ha within the BMU. Habitat potential in spring in the South Pipestone BMU is an interwoven matrix of moderate and good habitats. Very good habitats are limited in extent. Major portions of the Bow Valley within the BMU, the Pipestone and Little Pipestone Rivers, Molar Creek, and other tributaries are rated as very good, particularly in the summer. The Lake Louise BMU has 6,680 ha or 40% of the BMU rated as non-habitat. It also has just 2,297 ha or 14% of its land base rated as good or very good potential grizzly bear habitat on an annual basis, less than any other BMU in the study area. In spring, good and very good habitat potential for grizzly bears in the Lake Louise BMU is limited primarily to the Bow Valley. In summer, the amount of good and very good potential habitat expands to include all of the Bow Valley, and the majority of major tributary drainages; only higher elevation habitats are rated as moderate, poor, or non-habitat. Very good habitat is more extensive and contiguous in the summer than in spring, particularly in the Bow Valley. Potential habitat rated as good is almost as extensive in the fall as during the summer; however, the amount of very good habitat declined and is more fragmented in the fall.

The Lake Louise BMU sustains the highest levels of human use in the study area. Day use probably exceeds several thousand hikers per month in the summer on many of the popular trails and there are trails in every valley. Use of hiking trails was rated as low (<100 users/month) during the spring since most are still snow covered. However, during the summer and fall virtually all human disturbances were rated high (>100 users/month) throughout the BMU. The Bow Valley within the BMU is heavily impacted by the Village of Lake Louise and surrounding outlying commercial accommodations. In addition, the TransCanada Highway passes through it and the zones of influence surrounding the Bow Valley Parkway, CP Rail, and Skiing Louise’s activity area impinge on the BMU. Human use levels in the Skoki BMU were ranked second among the 4 BMU’s in the study area, well below those in the Lake Louise BMU, but higher than use levels in Baker and South Pipestone. Overall, human use in summer is high, exceeding >100 users/month on most trails within the Skoki backcountry, including day-use hiking loops to Lake Merlin, and around Skoki and Fossil Mountains. Spring and fall use in the backcountry was rated low since these high elevation trails are often not snow-free before mid-June and become snow-covered by early October. Most human use in the Baker Creek BMU occurs in the Bow Valley. The Bow Valley Parkway and CP Rail are within the BMU while the TransCanada Highway is outside, but its zone of influence affects the BMU. The Baker Creek Trail is designated low use throughout the 3 seasons with the exception of the south end during the summer months when it is frequently used by guests of Baker Creek Chalets. Human use of the South Pipestone BMU is concentrated in the upper Bow Valley along the Icefields Parkway. Human use in the backcountry was rated as low during all 3 seasons.

Realized habitat maps were developed for each BMU in May, August, and October. These maps indicate the extent to which the amount and distribution of grizzly bear habitats in all BMU’s are altered by human disturbance. This has many effects on bears within the BMU. Three effects are discussed relative to realized habitat within each BMU. First, the extent of grizzly bear habitat within the BMU is reduced. There are fewer places for bears to forage. Second, the sizes of the remaining patches of good and very good grizzly bear habitat are reduced. There are fewer places where grizzly bears can remain within the BMU without being disturbed by humans. Finally, linkages of good and very good habitat between larger pockets of undisturbed lands are reduced in size and number. Further fragmentation of a naturally-fragmented landscape makes it more difficult for grizzly bears to move throughout the BMU’s without contacting humans.

A comparison of the realized and potential habitat in the Skoki BMU in May shows a reduction in the availability of predominantly good and very good habitat ratings to moderate and poor habitats in the Bow Valley in the vicinity of the Skiing Louise lease. Approximately 1/4 to 1/3 of the Bow Valley’s good and very good habitat has been downgraded to moderate or poor habitat. In addition, connectivity of bear habitats on either side of the Skiing Louise lease at lower elevations within the Bow Valley is compromised. This situation is exacerbated in summer and fall. There is less good and very good habitat within the Bow Valley because of increased human use and the remaining patches are smaller than in spring. In the backcountry the situation is similar. However, the landscape at higher elevations is naturally more fragmented than in the Bow Valley, and the effects of additional fragmentation on potential grizzly bear habitat at higher elevations are more severe. Travel routes through Boulder Pass, Deception Pass and Packer’s Pass are rated as moderate to good potential habitat in all 3 seasons. However, the effects of human use in summer result in realized habitat values that are predominantly poor. In summer, moderate and poor realized habitat values dominate the landscape around Skoki Lodge and its network of day hikes, and in the vicinity of the backcountry campgrounds at Baker Lake and Red Deer Lakes. HE values for the Skoki BMU in spring, summer, and fall are 88.3%, 81.0%, and 87.7%, respectively.

Realized habitat in the Baker BMU contrasts the effects of human use of the Bow Valley with those in the Baker Creek drainage. The TransCanada Highway, the Bow Valley Parkway, CP Rail, and outlying commercial accommodation combine to drive all potential habitat values in the valley bottom to realized values of less than 0.5 on the 10-point scale (non-habitat) in all seasons. Human use on the Baker Creek Trail lowers habitat values from good to moderate in certain lower portions of Baker Creek, particularly in spring. Outside of lower elevations in the Bow Valley, linkages between good and very good realized habitat polygons are relatively intact in the Baker BMU. HE values for the Baker BMU in spring, summer, and fall are 78.8%, 76.5%, and 78.4%, respectively.

Realized habitat in the South Pipestone BMU again demonstrates the differences between human use of the Bow Valley and the backcountry. Although the Bow Valley is rated as predominantly good and very good potential habitat for grizzly bears, realized habitat values are poor when the effects of the Icefields Parkway are factored in. Realized habitat values in the Pipestone River drainage change little from their potential as a result of low human use. Outside of the Bow Valley, good and very good habitat patches remain relatively large and well-connected within the South Pipestone BMU. HE values for the South Pipestone BMU in spring, summer, and fall are 92.6%, 92.7%, and 92.6%, respectively.

The effects of high human use on a naturally-fragmented mountain landscape is well-illustrated in the Lake Louise BMU. Most good and very good potential habitat in the Bow Valley and tributary valleys (e.g., Paradise Valley, Moraine Lake, Lake Louise) becomes poor realized habitat as a result of human disturbance in all seasons. Remaining fragments of good and very good habitat are scattered throughout the BMU with very poor connectivity between them. Once again, the Bow Valley represents the best potential habitat within the BMU, yet realized habitat is worst as a result of the concentration of motorized human activities in the valley. This concentration of activity in the Bow Valley also presents a serious blockage to grizzly bear movements within the larger landscape of the study area. HE values for the Lake Louise BMU in spring, summer, and fall are 47.2%, 37.1%, and 37.6%, respectively.

The Banff Park Management Plan recognizes that to fulfill the mandate of PC to protect ecological integrity and at the same time to continue to offer visitors the opportunity to enjoy a quality visitor experience, direct management of human use is required at a scale not currently practiced. HE was chosen as a means of quantifying the degree of human disturbance on large carnivores, and HE targets were chosen for carnivore management units as a quantifiable measure of ecological integrity. Within the management plan’s section titled "Effective Human Use Management", stated principles include "human use management will be based on the desired effectiveness of each Carnivore Management Unit". Since HE modelling for carnivores other than grizzly bears has not been undertaken, grizzly bear HE is currently being used as a surrogate. Carnivore management units in the plan are equivalent to BMU’s in the grizzly bear HE model. Baker, South Pipestone, and Skoki BMU’s have summer targets of >90% in the management plan; only the South Pipestone BMU currently reaches that level. Skoki and Baker are 9.0% and 14.5% less than their target HE’s. Although the Lake Louise BMU has the lowest target of all BMU’s in the study area at >60%, it is also farthest from the target with an HE value for summer 22.8% below 60%.

Several human use management scenarios were tested to determine the degree of change required to increase HE values within the 4 BMU’s. Comparing HE values within the Lake Louise BMU in spring versus summer and fall indicate the changes required to significantly raise HE values in that BMU. The change from low to high use on all backcountry trails decreased HE for the BMU by about 10%. Increases in HE to reach the target set out in the management plan for the BMU will require drastic changes in human use. In the Skoki BMU, scenarios that significantly reduce human use in the Bow Valley would result in HE values above 90%. For example, if summer use of the Skiing Louise lease was capped below 100 users per month (ski area maintenance only) and human use in Skoki’s backcountry was also kept low (<100 users per month), the resulting HE value would probably meet the target set out in the management plan. Decommissioning the Baker Creek Trail and trails associated with it increases HE in that BMU by 2.5% over the current use scenario in August. Achieving HE of over 80% in the Baker BMU requires severe curtailment of human activities within the Bow Valley since the loss of HE within the BMU is principally in that portion of the BMU. As an example, the decommissioning of the Bow Valley Parkway and associated human developments (e.g., Corral Creek picnic area, Protection Mountain campground, Baker Creek Chalet, Baker Creek Trail) would increase HE by 8% to 84.5% in August. These human use scenarios serve to emphasize the extent to which grizzly bear habitat in the study area has been compromised, and the kinds of changes to human use that will be necessary to bring HE values to targets set out in the Banff National Park management plan.

Grizzly bear movements and use of habitat in the vicinity of human developments varied between seasons and years, as well as between bears. Core home ranges of the 3 adult female bears radio tracked during this study included a wide variety of human infrastructure. F30’s core home ranges in spring and summer included the Skiing Louise lease and in particular, the front side of Whitehorn Mountain. F30 used the Back Bowls, the Temple area, and Wolverine Bowl every fall. F46 also used the Skiing Louise lease during the spring and early summer in most years. However, she was located on the front side of Whitehorn just once in 1996. She was not usually located within the Skiing Louise lease in the fall, although she sometimes used the upper end of Corral Creek between Richardson Ridge and Wolverine Bowl. F36’s core home range included Num-Ti-Jah Lodge at Bow Lake. Human activity in these areas was frequent and in some cases continuous during daylight hours.

Reactions to roads by these 3 bears appeared to depend on traffic volume and roadway width. F36 was not documented crossing the TransCanada Highway, but did cross the Icefields Parkway on a regular basis, at times more than once per day. F30 and F46 moved back and forth across the Bow Valley Parkway. However, neither bear was documented crossing the TransCanada Highway which bordered their home ranges to the south. The TransCanada Highway carries over 1,600 vehicles per hour on a typical afternoon in August, while traffic volumes on the Icefields Parkway and the Bow Valley Parkway are just 25% of that. On the Skiing Louise lease, the roads to Temple Lodge and to other hill facilities on both the front and back side of the ski hill are closed to public travel, but are used several times a day by Skiing Louise staff and others with permission. It lies in the heart of F30’s and F46’s spring and summer ranges and they crossed it as much as several times per day, both during the day and at night.

Hiking trails including some with human use exceeding thousands of users per month in the summer crisscross the home ranges of all 3 grizzly bears; their selection of home ranges did not appear to avoid areas with hiking trails. A quantitative analysis of grizzly bear habitat use in the vicinity of trails is beyond the scope of this study. However, levels of human use on trails appeared to affect habitat use in the vicinity of trails. For example, bear use of habitat close to the heavily-used trail to Boulder Pass and Deception Pass, a trail in open terrain, typically occurred in late September only after human use of the trail system declined from high summer levels. Even at low use levels, crepuscular or nocturnal feeding along these trails was the norm.

Radio telemetry locations of F30 and F46 in the immediate vicinity of the Skiing Louise lease in spring and summer were used to test the hypothesis that F36 and F40 were located farther from ski runs and the base lodge during periods when there was human activity (07:00 – 18:00), than during periods of relative inactivity (18:00 – 07:00). In spring and summer, both F30 and F46 tended to be closer to ski runs and the base lodge at night than during the day. In addition, both bears tended to be closer to the ski runs than to the base lodge in spring and summer.

Current thinking within management agencies is that we should be managing for wary grizzly bears. In the Eastern Slopes Grizzly Bear Project, wary bears used higher-quality habitat and moved less than habituated bears. Bears living in lower quality habitat have reduced energy input. Increased movements result in greater energy expenditures for bears. Overall, the energy balance of habituated bears that do not have access to human foods will be lower than wary bears in the same ecosystem. Beyond maintenance requirements, adult female bears require energy for reproduction. These data suggest that habituation could reduce the reproductive output of an adult female grizzly bear; that is, she may produce fewer offspring over her life span. Therefore, habituation has the potential to depress natality in a regional population. Given the naturally-low reproductive output of grizzly bears, this could reduce the long term viability of grizzly bear populations within protected areas like Banff National Park.

The grizzly bear population within the Lake Louise study area is probably at risk based on the analysis of data presented in this report and additional analyses of data from the Eastern Slopes Grizzly Bear Project (Benn 1998, Gibeau et al. 1996, Gibeau 1998, Gibeau and Herrero 1999, Gibeau et al. 1999a,b). HE is seriously compromised by human development in the Lake Louise, Skoki, and Baker BMU’s. In particular, the Bow Valley, where grizzly bear habitat potential is greatest, is negatively affected by the TransCanada Highway, the Bow Valley Parkway, the CP Railway, the Village of Lake Louise and outlying commercial accommodation in the vicinity, and the Skiing Louise lease. Linkage zone analysis (Gibeau et al. 1996) indicates that these developments have created a significant filter to bear movements both back and forth across and up and down the Bow Valley. Radio telemetry data from the East Slopes Grizzly Project supports this conclusion (Gibeau et al. 1999a). Core security analysis (Gibeau et al. 1999b) shows that grizzly bears in the study area survive in one of the most human-influenced landscapes where they still exist. Reduced HE, severed landscape linkages, and low percentages of land free of human encroachment mean that these grizzlies must frequently encounter humans. High encounter rates often lead to habituated bears, and habituated bears have significantly higher mortality rates than wary bears. The examination of grizzly bear mortality patterns in the Lake Louise region concludes that Lake Louise has been and continues to be a mortality sink within the larger Central Canadian Rockies Ecosystem (Benn 1998). Significant changes to human land use patterns are required in the Lake Louise area to reverse these trends.