Grizzly bear (Ursus arctos) COSEWIC assessment and update update status report: chapter 4

4. Habitat

4.1 Definition

Grizzly bears are habitat generalists. They can be found from sea level to high-elevation alpine environments. In Canada they occupy habitats as diverse as temperate coastal rain forests and xeric Arctic tundra. Although they have a carnivore’s feeding and digestive anatomy, grizzly bears are functionally omnivorous and many are primarily herbivorous. Habitat associations are strongly seasonal and typically reflect local phenology. In mountainous regions this may result in seasonal migrations along an elevational gradient.

Grizzly bear habitat use has been widely described for most ecoregions (e.g., Schwartz et al. In press). This report focuses on contributions to the literature over the past 10 years, and especially those specific to Canada.

Habitat-use patterns of grizzly bears in the central Arctic have been recently described. Gau (1998) defined 5 bear seasons according to observed changes in bear diets, and used direct observations to assess habitat selection. During spring, bears selected bedrock habitats and other relatively snow-free sites. Wetland types, especially those with cover, were selected during early and mid-summer. In late summer, bears concentrated on eskers (ridges of gravel and sand established by melting glaciers), coincident with the ripening of berries. Habitats selected during fall were wetlands and mesic or mat tundra.

McLoughlin et al. (2002a) used resource selection functions, satellite telemetry data, and classified Landsat imagery to evaluate habitat use by grizzly bears in the same area of the central Arctic. Bears generally selected home ranges with disproportionate prevalence of esker, tussock/hummock successional tundra, lichen veneer, birch seep, and tall shrub riparian habitats. Within individual home ranges, bears selected eskers and riparian tall shrub habitats.

The high-density of an interior grizzly bear population in southeastern British Columbia (BC) was attributed mostly to productive berry fields resulting from extensive wildfires 50-70 years earlier (McLellan and Hovey 2001a). Avalanche chutes and riparian patches were important habitats in this area before and after berry season. Regenerating cutblocks were avoided during all seasons.

Physiographic and vegetative descriptions of grizzly bear habitats exist for many parts of Canada. However, anthropogenic attributes are increasingly taking precedence over biophysical features as determinants of grizzly bear habitat quality. Human activities can influence how bears are able to use potential habitat. In areas where bears are not habituated, they avoid zones of human activity (McLellan and Shackleton 1988; McLellan 1990). The resulting reduction in habitat effectiveness can extend over a land area much larger than that occupied by the development itself. Consequently, assessments of grizzly bear habitat commonly apply indicators of residual habitat effectiveness in consideration of the secondary effects of human activities (USDA For. Serv. 1990; Gibeau 1998, 2000). Recently, efforts to model security areas for grizzly bears (areas where bears can meet their energetic needs while choosing to avoid humans) have been used to help direct land-use planning for grizzly bear conservation (Gibeau et al. 2001). Security areas are those which consist of suitable habitat, are large enough to meet minimum daily area requirements for foraging, and which are outside of zones of influence of human activities. In southern Alberta and BC, Gibeau et al. (2001) estimated that minimum size of grizzly bear security areas was 9 km2. Minimum areas required to meet energetic needs can be expected to vary among environments. For example, in richer coastal areas, minimum areas may be smaller. On the Arctic tundra, minimum areas may be much larger.

4.2 Trends

Trends in habitat availability for grizzly bears in Canada since 1990 are not pronounced. Relative to the vast area of occupancy, little habitat has been directly lost. However, declines in habitat effectiveness have been documented in some areas and are likely in many others (e.g., Gibeau 1998). Increases in human developments, and particularly access, have degraded habitat quality throughout most of grizzly bear range.

4.3 Protection/ownership

4.3.1 Protected areas

Protected areas occur throughout grizzly bear distribution in Canada. In total, approximately 214 616 km2 of land within the current distribution is classified as protected (Tables table1, table2). This represents about 6.2% of the estimated total extent of occurrence in Canada, and about 8.3% of the estimated area of occupancy. This total, and the following discussion, excludes numerous small (generally <50 km2) protected areas. It is clear that most Canadian grizzly bears live on multiple-use lands.

 

Table 1. Federally designated protected areas within grizzly bear distribution in Canada.
Name and Location Land area (km2) First Nations subsistence hunting?
Waterton Lakes National Park, AB 525 no
Banff National Park, AB 6 641 no
Jasper National Park, AB 10 878 no
Kootenay National Park, BC 1 406 no
Yoho National Park, BC 1 310 no
Glacier National Park, BC 1 350 no
Mt. Revelstoke National Park, BC 260 no
Kluane National Park, YT 22 015 yes
Ivvavik National Park, YT 10 170 yes
Vuntut National Park, YT 4 345 yes
Nahanni National Park, NT 4 766 yes
Tuktut Nogait National Park, NT 16 340 yes
Thelon Wildlife Sanctuary, NT/NU 52 000 no
Total 132 006  
Table 2. Summary of provincial and territorial protected areas within grizzly bear distribution in Canada.
Location and Type Land area (km2) Comments
Alberta    
Provincial Parks 874 Excludes Wildland Parks and other protected areas with various land-use restrictions
Wilderness Areas 1 010  
British Columbia    
Yukon    
Territorial Parks 7 632 Grizzly bear hunting permitted
Kluane Wildlife Sanctuary 6 450  
Northwest Territories (NWT) and Nunavut   Several Territorial Parks, but with very small land areas
Total 82 610  

 

“Protected Areas” can mean different things. For example, hunting in provincial parks is prohibited in Alberta, but permitted in much of BC. National parks preclude consumptive use of natural resources, except that in the north subsistence hunting by First Nations is generally allowed. Particularly in southern Canada, activities including intensive recreational, residential, and infrastructure developments, and which may be clearly detrimental to grizzly bears, are commonly permitted in areas classified as protected. For this report, “Protected Areas” refers to areas which prohibit resource extraction industries, such as mining and timber harvest, and which have a mandate to generally protect grizzly bear habitat. However, since grizzly bear hunting is permitted in some of these areas, accidental, illegal, or management mortalities may continue, and habitat alteration may occur, not all can be considered grizzly bear sanctuaries.

Bear populations within each protected area are contiguous with areas outside park boundaries, and in some cases (e.g., Waterton Lakes and Revelstoke National Parks), protected areas may be too small to completely protect the entire home range of even a single bear. Other, larger, parks protect some resident bears, but those populations may be too small to be viable on their own. Most likely, protected areas may serve as core refugia, but are dependent on adjacent, unprotected areas to sustain viable bear populations.

In most cases, protected areas were established with primary goals other than grizzly bear conservation. As such, and because in most areas grizzly bears have very specific seasonal habitat requirements, many protected areas do not include substantial areas of high-quality bear habitat, and the best habitats may lie outside protected areas. This may be particularly true in mountainous areas where scenic values inspired creation of parks which are comprised largely of rock and ice.

4.3.1.1 Alberta

Three National Parks, 5 Provincial Parks, and 3 Wilderness Areas protect grizzly bears and 19 928 km2 of bear habitat in Alberta (Alta.). This is 10% of the estimated 200 000 km2 (Alta. Env. Prot. 1997) of occupied grizzly bear range in Alberta. Additional areas such as Wildland Parks, Natural Areas, and Ecological Reserves, provide some restrictions on land-use activities, but their status varies and many are small relative to grizzly bear life history needs.

4.3.1.2 British Columbia

Four National Parks within grizzly bear range in BC exclude resource extraction and hunting on a total of 4326 km2. Province-wide, there are 717 Provincial Parks, Recreation Areas, and Ecological Reserves, totalling 97 552 km2. Some of these are outside grizzly bear distribution, many are very small, and land-use restrictions are variable. Resource extraction is prohibited in 61 larger (>50 km2) Provincial protected areas totalling 67 142 km2 within grizzly bear range, but hunting is permitted in nearly all of them. One protected area, Khutzeymateen Provincial Park (443 km2), was established specifically as a grizzly bear sanctuary, and hunting there is prohibited below 1000 m elevation above sea level. Grizzly bears occupy about 750 000 km2 in BC, and “protected” areas cover about 9.5% of that.

4.3.1.3 Yukon

Three relatively large National Parks in the Yukon protect a total of 36 530 km2 of potential grizzly bear habitat. Aboriginal subsistence hunting is permitted in all. Resource extraction and other habitat perturbations are also restricted in Tombstone Territorial Park, Fishing Branch Wilderness Reserve, and the Kluane Wildlife Sanctuary. Protected areas in the Yukon total 50 612 km2, about 10.5% of the Territorial area.

4.3.1.4 Northwest Territories and Nunavut

Grizzly bears occur within 2 National Parks in Northwest Territories, but none in Nunavut. First Nations hunting is permitted in both. The Thelon Wildlife Sanctuary straddles the NWT/Nunavut boundary and excludes all hunting or resource extraction. The total protected area is 73 106 km2.

4.3.2 Land ownership

The majority of grizzly bear habitat in Canada is publicly owned. Public land comprises 92% of British Columbia and 60% of Alberta. Private lands in both provinces are concentrated in the south and in urban areas, and disproportionately include areas outside grizzly bear distribution. Therefore, public land ownership within grizzly bear distribution is likely higher than the provincial averages, especially in Alberta. Almost all land in the Yukon, Northwest Territories, and Nunavut is publicly owned.

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