in the Canadian
Rockies
Bears and
Habitat
Bears and
Roads
Bears and
Science
Habitat Requirements
Bears and
Habitat
Black
Bears
Relative to grizzly
bears, there has been little recent research on the habitat requirements
of black bears in the Central Canadian Rockies. The following information
focuses on black bear diet and ecoregion selection.
What do black bears eat?
From 1986-88, Kansas et
al conducted a comprehensive ecological study of black bears in Banff
National Park (BNP). Based on analysis of scats and feeding signs, they
divided the “typical” black bear year into four seasons and identified major food
items for each:
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Green-up (den exit to mid-June): horsetails, grasses and sedges
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Ant (mid-June to mid-July): ants and ant larvae
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Buffaloberry (mid-July to end-August): buffalo berry
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Post-buffaloberry (end-August to den entry): crowberry, bearberry, juniper and whitebark pine nuts (Kansas et al 1989)
Their report also detailed the use of manmade inclusions, ecoregion and ecosite/vegetation type use, home range sizes, denning habitat and a variety of information not directly related to habitat.
Where is the best black bear
habitat in the mountains?
A significant habitat-related finding of the BNP
study was the importance of low elevation valley bottoms (the “montane”
ecoregion) to black bears. The researchers documented black bear use of
the montane ecoregion for 40.1 - 42.7% of the time during the first 3 bear
seasons, and stated that this level of use “…is particularly noteworthy as
this ecoregion encompasses less than 4% of the total areas of BNP.” 8
Why is it
important?
The limited
extent of the montane and the associated vegetation types that provide
cover for black bears was felt to be a major factor contributing to the
low numbers of black bears in Banff’s front ranges.
-
“…front range river valleys generally lack sufficient cover for black bears…Our intensive field studies show that such areas are crucial during the green-up season and are also undoubtedly important for cub escape cover. Given that grizzly bears are very common in the area, this paucity of cover near important spring food sources may limit black bear occurrence year-round.” 9
Based on these findings, they recommended that the montane “…should be protected from developments that would diminish the availability of Montane ecosites to black bears.” 10
The need to protect the montane for black bears is especially evident in the Bow River valley of BNP. The Bow valley contains 80% of the montane in BNP, but it is also the most highly developed area within the park. Thus, black bears attempting to exploit quality montane habitat are “forced into contending with human developments in the Bow River valley, thereby increasing the probability of vehicle-wildlife collisions and management removals.” 11
Grizzly
Bears
This
section focuses on grizzly bear diet, its influence on habitat use, and on
suitable grizzly bear habitat.
What do grizzly bears
eat?
Hamer and Herrero conducted detailed
analyses of grizzly bear habitat requirements in Banff National Park (BNP)
during the late 1970’s. Their report identifies the following important
seasonal grizzly bear foods:
-
hedysarum roots
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horsetails, grasses, sedges
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cow parsnip, mountain sorrel
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buffalo berries
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ungulate kills or carcasses
-
ants. (Hamer and Herrero 1983)
They also identified related habitat-types and their seasonal use by grizzly bears, den site characteristics, and a variety of other habitat related information.
Because of the variation in vegetation between different regions within the Rockies, foods utilized by regional grizzly bear populations can differ. For example, blueberries and cow parsnip are present in much greater abundance on the west slopes of the Rockies than they are on the east slopes where BNP is located. A three year study of grizzly bears in Yoho and Kootenay National Parks (situated on the west slopes of the Central Canadian Rockies) found that as well as exploiting the foods identified by Hamer et al in BNP, grizzly bears in their study area relied heavily on cowparsnip in the spring, and blueberries during the berry season. (Raine and Riddell 1991)
Why is it important?
The abundance and
quality of available foods can have a significant influence on regional bear population
densities. Researchers studying grizzly bears in the Flathead River drainage (southeastern
British Columbia sub-ranges of the Rockies) have reported that:
-
“The Flathead and contiguous Waterton Lakes National Parks are so far the only study areas in North America that contain all major bear foods found across the interior of the continent, and in particular, both major berry species, huckleberries and soopolallie. This observation supports the hypothesis that a favourable food base in the Flathead is partially responsible for the high density of bears found there.” 12
Knowing the seasonal food habits of grizzly bears is also important from a management perspective, a point that was made by Hamer et al in their interim report:
-
“Food habits of grizzly bears Ursus arctos are a major variable associated with seasonal habitat preferences of the species. With the exception of movements associated with reproduction and denning, the search for food must be the primary motivating force behind the movements of undisturbed bears. A knowledge of the seasonal food habits of the various age/sex classes thus becomes a prerequisite to the management of areas occupied by grizzly bears. By being able to predict within certain probabilities the bears’ seasonal habitat preferences, it may be possible both to reduce the number of potentially dangerous man/grizzly bear encounters as well as to protect the bear population and its critical, seasonal habitat from excessive human disturbance.” 13
Where
is the best grizzly bear habitat in the Central Canadian
Rockies?
The Central Rockies
Ecosystem (CRE) is a vast landscape that encompasses approximately 40 000 km2.
However, the amount of land that is inherently “suitable” for grizzly
bears is surprisingly small.
Grizzly bear researcher Dr. Mike Gibeau used Geographic Information System computer software to map suitable grizzly bear habitat in the CRE. By “removing” areas of rock, ice, water, bare soil and lands above 2500m (grizzlies in the CRE generally don’t use areas above this elevation), 48% of the Mountain National Park landscape – this includes Banff, Yoho and Kootenay National Parks -- was shown to be inherently unsuitable habitat for grizzly bears. For Kananaskis Country this figure is 27%; results for British Columbia and Alberta Provincial lands within CRE are 27% and 12% respectively. As Gibeau states, the fact that much of the mountain national parks are not inherently prime grizzly habitat “is a new concept for many…National parks in the Canadian Rocky Mountains were originally selected for their scenic and tourism value, which is inherently not good habitat. Better habitat lies to both the east and west in human-dominated multiple-use lands.” 14