in the Canadian
Rockies
Bears and
Habitat
Bears and
Roads
Bears and
Science
Human
Impact
Bears and
Habitat
Efforts to quantitatively and qualitatively assess the impact of human development and activities on bear habitat and habitat-use are a major focus of recent bear research in the Canadian Rockies – especially with respect to grizzly bears. Significantly less information is available regarding human impacts on black bear habitat in the Canadian Rockies. Those studies that have been conducted tend to focus on specific features such as highways and railways.
Measuring the cumulative effects of development on grizzly
bears
The primary mandate of the Eastern Slopes Grizzly Bear
Project (ESGBP) which began in 1994 is “to
scientifically define the cumulative effects of development on the
regional grizzly bear population.”15 The project focuses on grizzly
bears in the Central Rockies Ecosystem which is one of the most highly
developed landscapes in North America where grizzlies still survive. (Herrero and Gibeau 1999)
ESGBP researchers have incorporated the three following habitat components and associated models into their assessment of the cumulative effects of development on grizzly bears.
Once developed, these models can be used as predictive tools by changing or “manipulating” certain variables, and then seeing how the modeled results respond to those changes.
Habitat
effectiveness
WHAT IS HABITAT EFFECTIVENESS
MODELLING?
“Habitat effectiveness models an area’s actual
ability to support bears given the quality of the habitat and the extent
of human disturbance.” 16
Habitat effectiveness analysis involves constructing a spatial, Geographic Information System (GIS)-based model that generally consists of two major “map layers” or components:
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habitat potential layer (reflects the inherent ability of the landscape to support bears)
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human disturbance layer (reflects the realized ability of the landscape to support grizzly bears after taking into account human disturbance)
By overlaying human disturbance onto habitat potential, the model produces Habitat Effectiveness Values which “estimate the percentage of habitat that is available after subtracting habitat alienated as a result of human influence.” 17
HABITAT EFFECTIVENESS IN
THE CENTRAL ROCKIES ECOSYSTEM
This analysis was applied in
Banff, Yoho, and Kootenay National Parks, Kananaskis Country and at a more
refined scale in the Lake Louise area of BNP.
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the Mountain National Parks analysis suggests “widespread habitat alienation in what is supposed to be core refugia for grizzly bears, questioning the ability of the landscape to support a viable population.” 18
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the Lake Louise analysis supports this statement as habitat effectiveness was determined to be “seriously compromised by human development” in 3 of the 4 Bear Management Units (BMUs) analysed. 19
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Kananaskis Country results were also cause for concern; they demonstrated that there is “considerable stress” on grizzly bears using 5 of 13 BMUs. 20
Security (Core)
Areas
WHAT IS SECURITY AREA
MODELLING?
Security areas are
“...areas where grizzly bears will be relatively secure from encounters
with humans; where bears can meet their energetic requirements while at
the same time choosing to avoid people.” 21
Security area analysis involves developing a
spatial, Geographic Information System (GIS)-based model that generally
consists of two “map layers” or components:
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Suitable habitat layer: a map identifying suitable foraging habitat patches of all sizes after accounting for landscape and human activity features.
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Minimum daily area requirement (m.d.a.r.): the minimum average daily foraging radius for a female grizzly bear (based on empirical data from wary female grizzly bears)
Overlaying these two components enables
researchers to eliminate from the suitable habitat layer all habitat
patches which are too small to meet the m.d.a.r. The remaining number of
patches and the size of them provide a concrete measure of the extent of
habitat fragmentation, especially if the analysis is completed for
historic, present and predicted future scenarios of human use.
(Gibeau et al 1996)
SECURTIY AREAS IN THE
CENTRAL ROCKIES ECOSYSTEM
Security area analysis was conducted
for the Central Rockies Ecosystem.
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Kananaskis Country, which has an intensive recreation mandate, had the highest percentage (40%) of land not secure due to human use (40%). It also had the greatest percentage (38%) of its land base within a zone of human influence (these are areas less than 500m from high human use features). (Gibeau 2000)
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42% of the National Parks landbase is inherently unsuitable for grizzly bears, contrasted with only 12% for Alberta multiple use lands. However, only 17% of National Parks land had high human influence, compared to 38% for Alberta multiple use lands. (Gibeau 2000)
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historic reconstruction of human-use circa 1950s and forecasting into the future circa 2050 (assuming status quo for human-use and no prescribed fire regime) shows a pattern of fragmentation and insularization of habitat within Banff and Kananaskis Country jurisdictions over time:
— the average size of secure habitat patches in Banff National Park decreased from 218km2 in the 1950s to 56km2 currently to 43km2 around 2050.
— increase in the number of patches from 13 to 39 to 39
A loss in the ability to foster wary
behaviour in grizzly bears accompanies this pattern.
(Gibeau and Herrero 1998)
Linkage Zone Prediction
Model
WHAT IS LINKAGE ZONE
MODELLING?
Landscape linkages are
“...usually understood as linear corridors of habitat that physically
connect larger habitat patches in a landscape mosaic.” 22
Within the specific context of the linkage
zone prediction model, the ‘landscape mosaic’ includes areas impacted by
human activities, and may be defined as “combinations of landscape
structural factors that allow wildlife to move through, and live in areas
impacted by human actions.” 23
Linkage zone
analysis involves developing a spatial, Geographic Information System
(GIS)-based model that consists of four “map layers” or components:
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human access route density: includes all roads, railways and high-use trails
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density and nature of developed human sites: each site is assigned a corresponding zone of influence based on level of human use
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presence or lack of hiding cover: determined from ecosite maps
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within a riparian area: stream course and other areas that are expected to meet criteria for bear foods and movements, and for specific “wet-site” vegetation types
Overlaying these components generates a
“combined danger score” (minimal, low, moderate and high – the higher the
score, the greater the “danger” to bears) that is the result of both the
level of human influence and the quality of habitat for bears in a given
area. These scores are then used to “identify and quantify potential areas
that can act as linkage zones between areas of habitat separated by
humans.”
(Source for all:
Gibeau et al 1996)
LINKAGE ZONES IN BANFF
NATIONAL PARK
Linkage zone analysis in Banff National Park and
surrounds produced the following results:
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east of the park, there are few potential opportunities for linkage zones
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including the Trans-Canada Highway fencing and wildlife crossing structures in the analysis produces a dramatic decrease in potential crossing areas.
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reconstruction of past human use levels (1950s) shows significantly fewer ‘moderate’ and ‘high’ danger scored values than at present, and linkage zones that are more extensive than at present.
(Gibeau et al 1996)
Effects of industrial resource extraction on grizzly
bears
Substantial effort has
been directed towards assessing the effects of industrial resource
extraction on grizzly bears. The Flathead
Bear Study (Flathead River drainage, Southeast
British Columbia), which began in the late 1970s and continues today, has
conducted a considerable portion of this research. This section contains
several highlights and conclusions from their many years of
research.
Potential effects of industry on grizzly bears
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“Most grizzly bears (Ursus arctos) live outside parks and reserves and often have to contend with, among other things, resource extraction industries. These activities can affect individual bears and therefore populations by: 1) causing strong, energetically expensive reactions by bears that disrupt their normal behaviour, 2) displacing bears from areas of human use, 3) altering habitats in which bears live, 4) disrupting the bears’ social system, and 5) industrial personnel killing bears or increasing mortality rates indirectly by improving access for hunters, poacher, other resource users, and settlers.” 24
Access into bear habitat as a result of industrial activity
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“In most cases, increased motorized access that results in a long term increase of human activity and/or settlement with consequent increase in bears being shot is the most significant aspect of industrial developments. If an industrial activity is connected with adequate guidelines to maintain important habitat, properly locate camps, incinerate garbage, restrict use of firearms, and close motorized access after the job is complete, the bear population probably will be maintained at a satisfactory level. Although many bears may be alive when an industry has completed its work, if access remains intact, the grizzly population is placed in a precarious position and may decrease in size and eventually be extirpated.” 25
Immediate responses to human activity and
implications for industry
McLellan and Shackleton examined the
immediate reactions of grizzly bears in the Flathead to a variety of human
activities between 1979 and 1986. Bear responses were categorized
according to several factors including: distance moved from the
disturbance, whether or not they moved into the nearest cover, the manner
in which they moved off (slowly or quickly).
Some selected findings and the related implications for industry are:
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bears respond differently to different human activities/stimuli based on their experience.
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bears showed stronger responses in open areas than in cover, and cover was particularly important in reducing responses of grizzly bears to terrestrial human activities (e.g., person on foot, moving car).
Implication: high-human-use areas such as roads should be constructed away from open areas to reduce disturbance. Conversely, where strong reactions of bears to humans are desired, such as at industrial camps or settlements, removing cover by clearing adjacent timber may be beneficial. -
the strongest reactions were to people on foot and reactions were stronger in areas of low human-use than in high human-use areas.
Implication: areas with known seasonal concentrations of bears could be closed to hikers to protect both bears and people
(Source for all: McLellan and Shackleton 1989)