Grizzly Bear Food and Habitat in the Front Ranges of Banff National Park, Alberta

Food and habitat used by grizzly bears (Ursus arctos) in the Front Ranges of Banff National Park were studied during 1976-80 using fecal analysis, feeding site examination, direct observation, and radio-tracking. Important foods included pink hedysarum (Hedysarum alpinum) roots, yellow hedysarum (H. sulphurescens) roots, bearberries (Arctostaphylos uva-ursi), graminoids, horsetails (Equisetum arvense), buffaloberries (Shepherdia canadensis), and Vaccinium spp. fruits. Most foods were eaten in dry meadows, shrubfields, or open forest. Horsetails were the only notable exception; many feeding sites occurred in mature forest. The alpine zone was unimportant as feeding habitat. Seasonal changes in diet and habitat use appeared to be related to plant phenology with bears eating plant parts which seemed to be at nutritious development stages. Hedysarum roots, the bears' major food, had significantly less crude protein and more fiber when plants were flowering than when they were in pre-leaf. Related to this, digging by bears was minimal during the mid-summer flowering period. Seasonal habitat use also appeared to be influenced by hedysarum phenology. As the spring digging season progressed, hedysarum diggings occurred more on north-facing slopes and at higher elevations, where phenology was retarded. Later-season root digging was inversely related to buffaloberry abundance: the volume of roots in feces during August-October was greater in 1976 and 1978, 2 years when buffaloberry abundance was significantly lower than in 1977 or 1979. We concluded that buffaloberries, known to be high in soluble carbohydrate, were preferred over hedysarum roots. During summer, grizzly bears ate horsetails in sites where the plants were in immature, nutritious development stages. The elevation of horsetail feeding sites was significantly higher in late July-August than in early July. Grizzly bears thus ate food high in soluble nutrients and low in fiber by making seasonal changes in both the food and habitat they selected. Int. Conf. Bear Res. and Manage. 7:199-213 This research documents the food habits and habitat use of grizzly bears in the Cascade and Panther valleys of Banff National Park. In addition, we have tried to understand why grizzly bears switched from 1 food to another, or moved from 1 habitat type to another. The quality, quantity, and availability of food at certain seasons or in certain habitat types were the variables considered in these analyses. This project was made possible through the cooperation of Parks Canada. In addition to financial support, we acknowledge the assistance of Parks Canada employees A. Anderson, K. Baker, P. Benson, L. Gilmar, J. Halstenson, J. Holroyd, P. Jacobsen, B. Leeson, G. Rogers, M. Rose, B. Vroom, M. Vroom, and P. Whyte. For field or technical assistance we also thank F. Anderka, C. Blyth, J. Courtney, J. Davies, A. Francoeur, K. Greer, D. Henry, A. H. Marsh, S. Oosenbrug, F. Raimer, L. Sinkey, T. Toth, and Y. Yzerman. R. T. Ogilvie and T. Toth analyzed and mapped the vegetation for this study. The Alberta Soil and Feed Testing Lab. analyzed forage samples. J. Alley and A. Flegel assisted in report preparation. Drs. P. K. Anderson, F. C. Dean, J. D. Henry, L. V. Hills, M. R. Lein, R. D. Revel, and F. J. Wrona commented on earlier manuscripts. Financial support was provided by Parks Canada, the Natl. Sci. and Engin. Res. Council of Canada, the Can. Natl. Sportsmen's Fund, the Univ. of Calgary, and Alberta's Rec. , Parks, and Wildl. Found. STUDY AREA The study area occupies approximately 250 km2 in the eastern slopes of Banff National Park, within the Front Ranges of the Rocky Mountains (Fig. 1). The continental divide is 45 km to the west. Glaciation has developed a gentle U shape to the study area's larger valleys, which run northwestsoutheast in major faults. Numerous smaller drainages dissect the intervening mountain blocks which, in conjunction with the moderate relief (elevations range from 1,600 to 3,000 m), result in a complex juxtaposition of slopes with differing aspects, elevations, and steepness. Abrupt changes regularly occur within 2-3 km or less of any 1 point in the study area. The Front Ranges are separated from the Pacific Ocean by the Coastal and Columbia mountains and by the main ranges of the Rocky Mountains. As a result, the climate in the study area is essentially continental. According to extrapolations by Janz and Storr (1977:325), certain portions of the main valleys likely are semiarid ( < 50 cm precipitation/year). This rainshadow effect is exacerbated by the drying effect of the warm, westerly, chinook (foehn) winds that characterize the Rocky Mountains east of the continental divide. Many southeastthrough west-facing slopes (135? -270? ) are forest-free below the normal treeline, in part because of low precipitation and the drying influence of strong chinook wind. 200 BEARS-THEIR BIOLOGY AND MANAGEMENT