Grizzly Bear Population and Habitat Status in Banff National Park (1996)


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Gibeau, Michael L., Stephen Herrero, John L. Kansas, and Bryon Benn. 1996. Grizzly bear population and habitat status in Banff National Park. A report to the Banff Bow Valley Study Task Force. By the Eastern Slopes Grizzly Bear Project. 62 pp.

— EXECUTIVE SUMMARY —

Our results demonstrate that grizzly bear population and habitat in the Banff Bow Valley, Banff National Park, and the Central Rockies Ecosystem have been seriously stressed by the combined effects of human development and activities. The situation is urgent, especially for Banff Park which is designated as a protected area. We present a series of conclusions and recommendations to address the problem.
The status of the grizzly bear population and habitat are excellent indicators of ecological integrity in the Banff Bow Valley and the significantly larger regional ecosystem, the Central Rockies, upon which grizzly bears depend. By maintaining a healthy grizzly bear population we suggest that most other elements and processes of terrestrial ecosystems will also be maintained.
The grizzly bear is an excellent indicator species for ecological integrity because of certain biological traits. In the Central Rockies Ecosystem they have few young (on average about .5 cub per year during their reproductive years). They range over large areas (for males, home ranges may exceed 2000 km2), and they occur at low population densities (estimated at 1/62.5-101.6 km2). Furthermore, they are prone to direct conflict with people. The combination of these biological traits interacting with people’s proclivity to develop and use grizzly bear habitat usually results in compromised grizzly bear populations and habitat. As omnivores and apex predators, grizzly bears are one of the first species to be lost from an area as a result of land development activities. If grizzly bear populations are healthy then human impacts are being well managed.
In places where human development and activities are prevalent, such as Banff Park and surroundings, Yellowstone Park, or the Provinces of Alberta and British Columbia, the majority of adult grizzly bear deaths are caused by people. We review the history of grizzly bear population declines that have resulted from human-induced mortality and habitat impacts in Banff Park, the Province of Alberta, and the contiguous United States.
To understand the current status of the grizzly bear population and habitat in the Banff Bow Valley, Banff Park, and the Central Rockies Ecosystem we used four different research approaches. Our first area of research involved analyzing the Banff Park grizzly bear mortality and translocation data bases for the period of 1971 to 1995. The other research approaches applied three modeling techniques, including habitat effectiveness, core area analysis, and linkage zone prediction.
Analysis of the mortality database show a minimum of seventy-three recorded mortalities and removals for Banff Park from 1971 to 1995. The average annual number of mortalities/removals for this period was exceptionally high (2.92/year or 4.87 – 3.65% of the population based on a population estimate of 60 or 80 bears). The Province of Alberta has established a harvest target of 2% of an area’s grizzly bear population estimate and currently manages the population to keep total mortality at roughly 4% to allow for population growth (Nagy and Gunson 1990). Based on a Banff Park population estimate of 60 or 80, this would allow an average annual mortality/removal rate of 1.2 – 1.6/year. Five year average annual mortality/removal numbers varied from a low of 1.6/year to a high of 6.2/year. A decreasing trend in mortalities was exhibited from 1981 to present. This may have been partly due to improved garbage management. Given the grizzly bears’ low reproductive capability, it may also have been the manifestation of a significant decline in the local bear population following high annual mortality prior to this period.
Knight and Eberhardt (1985) reported that the death of 1 or 2 adult females could have significant, negative population consequences for Yellowstone grizzlies. In Banff National Park the female cohort accounted for 56% (24 of 43) of all known mortalities/removals since 1971, and 88% (16 of 18) of mortalities/removals since 1983. This is the highest female mortality/removal rate for a 10+ year period reported for any grizzly bear population.
Mortality type analysis revealed that problem wildlife control actions accounted for 71% of grizzly bear mortalities, followed by highway and railway kills (17%), unknown (8%), and natural death (3%). Over 90% of grizzly bear mortalities in Banff Park occurred in frontcountry areas, within a 500m zone surrounding roads and human infrastructure.
Habitat effectiveness modeling is the major component of cumulative effects analysis developed to quantitatively and qualitatively assess the effects of human actions on grizzly bears and their habitat. Results indicate a significant portion of the landscape is only moderately productive habitat. The disturbance component of the model suggests wide spread habitat alienation in Banff National Park, an area considered core refugia for grizzly bears in the Canadian Rocky Mountains. Over all, the model suggests that the ability of the landscape to support bears has been significantly reduced.
There is a strong case for preserving areas were grizzly bears will be secure from encounters with humans; where bears can meet their energetic requirements while at the same time choosing to avoid people. Such core security areas would foster the wary behavior in grizzly bears that most managers consider desirable. Core area analysis uses GIS technology to identify areas that are functional at the scale of individual foraging bouts for adult female bears. Results of this analysis showed a progressive apparent loss of security areas starting with 1950, through the present, and into the future depicting an ever increasing deterioration of habitat within Banff Park. Fragmentation and insularization of core habitat within the Banff Park landscape are evident as well as a loss in the ability to foster wary behavior in grizzly bears.
Linkage zones combine landscape structural factors that allow wildlife to move through and live in areas impacted by human actions. This technique assesses the degree of habitat fragmentation caused by the cumulative effects of human actions in an area. A linkage zone prediction model was developed in the U.S. to identify and quantify these areas of potential carnivore crossing and use in mountain valleys. Results depict a dramatic decrease in potential crossing areas over time. Fencing of the Trans Canada Highway has had a significant effect on the ability of grizzly bears to move across the Bow River Valley. Four years of research indicate that no female bears have crossed the fenced sections of the highway (5300 telemetry relocations). The implications of such a barrier on both grizzly bear genetics and demographics are unknown. Fenced sections of the Trans Canada Highway could have profound effects on grizzly bear passage across the Bow River Valley and ultimately movement throughout the Central Canadian Rocky Mountains.
The results from our four research approaches, combined with data from ongoing research efforts by the Eastern Slopes Grizzly Bear Research Project, and the results of decades of published research on grizzly bear ecology throughout North America, allowed us to reach conclusions and to make recommendations regarding grizzly bear management.
Conclusion one: The population status of grizzly bears in the Central Rockies Ecosystem is not scientifically known. However, available evidence suggests a stressed population.
Recommendation 1: Implement an interagency mortality/removal monitoring system for the Central Rockies Ecosystem which brings together data from Parks Canada, and the provinces of Alberta and British Columbia.
Recommendation 2: Average annual mortality/removal of grizzly bears for Banff Park, calculated as three year running averages, should not exceed 1% of the current population estimate. Mortalities/removals of females must be less than males.
Recommendation 3: Parks Canada should request that B.C. and Alberta establish a temporary no hunting zone for grizzly bears surrounding Banff Park. This zone would remain until population recovery or viability is scientifically demonstrated.
Recommendation 4: Continue the demographic studies currently being carried out by the Eastern Slopes Grizzly Bear Research Project until sufficient data are available for scientifically valid population trend and number estimates. This will take between five to ten years of field research to collect. These data will be essential for determining annual allowable mortality/removals in the Central Rockies Ecosystem.
Recommendation 5: Because of documented population stresses, management of grizzly bears in Banff Park must become conservative. The burden of proof regarding the potential impacts of development should require the proponent to prove there would be no significant local or cumulative effect on grizzly bears.
Conclusion two: The grizzly bear population in the Central Rockies Ecosystem moves freely across jurisdictional boundaries. Habitat and mortality/removals must be managed regionally for effective grizzly bear management.
Recommendation 6: Establish an interagency, multi-stakeholder group with significant responsibilities for regional grizzly bear management.
Conclusion three: Management of grizzly bear-human conflict needs to be dealt with more proactively to prevent the need for management removal of bears from the system.
Recommendation 7: Establish a knowledgeable Bear Management Team in order to bring grizzly bear removals from Banff Park to acceptable levels, and to provide for high standards of human safety.
Conclusion four: Habitat effectiveness for grizzly bears in Banff National Park is unacceptably low.
Recommendation 8: Prepare access and development management plans for each of the Banff Park Bear Management Units (BMUs). The objective of the plans would be to increase habitat effectiveness for grizzly bears.
Recommendation 9: Banff Park should continue to support research by the Eastern Slopes Grizzly Bear Research Project aimed at empirically determining disturbance coefficients specific to the Central Canadian Rockies Ecosystem.
Conclusion five: Grizzly bear habitat units (core security areas) are becoming increasingly smaller. This habitat fragmentation is resulting in apparent functional loss of habitat, and possible genetic isolation as a result of developments and human activities.
Conclusion six: The Trans-Canada Highway appears to be a significant barrier for grizzly bear movement, thus causing habitat fragmentation.
Recommendation 10: Ensure effective, multiple crossings for grizzly bears, especially in divided and fenced sections of the Trans Canada highway, to reduce habitat fragmentation effects. The implementation of recommendation 8 would also aid in addressing the problem of habitat fragmentation identified by the core security area analysis.
Conclusion seven: Habitat quality for grizzly bears appears to have declined significantly during the past approximately 60 years.
Recommendation 11: Restore fire to its historic, natural regime in all possible portions of Banff Park. Fire has been nearly eliminated from its natural role in the landscape for the past 60 years, and grizzly bears are adapted in the Central Rockies Ecosystem to forage in high quality, post-fire environments.
Conclusion eight: Significant, direct loss of Bow Valley, montane ecoregion habitat has occurred.
Recommendation 12: Further development should not be allowed in the montane ecoregion beyond that necessary for Trans-Canada Highway redevelopment. De-development should be considered for all non-essential developed areas. This could reclaim some lost montane habitat and would address other habitat related issues such as habitat alienation.
Complete discussions and elaboration of recommendations flowing from these conclusions are found in the final section of this paper.

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