Changes in diets of wapiti during a hunting season.

This study was conducted to assess the impact of hunting on diets of a wapiti (Cervus elaphus) population in west-central Alberta, Canada. During special winter hunts, consumption of rough fescue (Festuca scabrella) decreased from 86.9% to 34.3%, while browsing increased. The contribution of wild rye (Elymus innovatus) and wheatgrass (Agropyron subsecundum), mostly growing in forested areas, increased 15-18%. After the hunting seasons, animals returned to the same diet they had selected previously. Browse had significantly higher crude protein contents, but lower dry matter digestibility than grasses. In spite of submaintenance crude protein contents of grasses, undisturbed wapiti appeared to prefer grazing to browsing. The potential impact of human activities on wapiti (Cervus elaphus) has received considerable attention. Several authors have reported changes in distribution, habitat selection, and behavioural patterns caused by recreational or industrial activities (Ward et al. 1973, Perry and Overly 1976, Lyon 1979). Attempts also have been made to relate levels and types of human disturbance to energy expenditures (Ward et al. 1976). However, an assessment of the impact of human activities on welfare and productivity of ungulate populations is still limited to approximate determinations of habitat loss and to general statements about consequences of altered distribution patterns. Morgantini and Hudson (1979) reported the avoidance of traditional ranges by wapiti during winter hunting seasons. This report documents a major change in food habits accompanying this redistribution. Study Area and Methods The study was conducted on the Ya Ha Tinda Ranch, a traditional winter range in west central Alberta, Canada. The area, 35 kM2, is located in the foothills of the Rocky Mountains, approxiAuthors are respectively, president, Wildland Resources Consultants, and associate professor, Department of Animal Science, University of Alberta, Edmonton, Canada, T6G 2P5. At the time of the study, the senior author was graduate research assistant with the University of Alberta. We thankfully acknowledge the financial support of the Alberta Fish and Wildlife Division and the cooperation of Parks Canada. Manuscript accepted April 17, 1984. mately 10 km east of Banff National Park. It consists of a rolling open rough fescue (Festuca scabrella) grassland surrounded by aspen (Populus tremuloides) and lodgepole pine (Pinus contorta) forests. Willows (Salix spp.) and dwarf birch (Betula glandulosa) are abundant in the grassland-forest ecotone. Due to the surrounding mountains, the area is subject to mild winter weather while westerly winds keep grasslands largely snow-free. At the time of the study, 1976-77 and 1977-78, approximately 400 animals wintered in the valley. Most were cows and calves with a few young bulls. These animals comprised a major portion of the wapiti inhabiting the northern half of Banff National Park. Between 1969 and 1975, in response to presumed overgrazing, special hunting seasons (either sex) were held during the first 2 weeks of January and February. Hunting was allowed only 3 days a week. From 1976 to 1978, the special season was restricted to males. Every winter 200 licenses were issued, 50 for each week of the hunt. This study focused on food habits prior, during, and after the hunting seasons of 1977 and 1978. Diet composition was estimated by identification of plant cuticular fragments in feces (Hansen et al. 1973, Dearden et al 1975). Every month, 20 samples of fresh wapiti pellets were collected. During the hunting season, pellet collection was restricted to the last day of the hunt to allow sufficient time for forage passage through the digestive tract (Uden 1978). During the winter of 1977, the late arrival of animals on winter range in December did not allow fecal collection before hunting. Also, samples could not be collected during the February hunts of 1977 since high hunting harassment forced animals to abandon the entire area and seek refuge on alpine ranges and in Banff National Park. Approximately 5 g from each oven-dried sample were combined into one composite sample representing monthly diets. These were sent to the Composition Analysis Laboratory, Colorado State University, for analysis at 100 microscope fields per sample. To assess forage quality, composite grassland forage samples were collected during the winter of 1977-78 from 10 randomly distributed 20 X 50-cm plots. Composite samples were considered adequate for this study because of the homogeneous plant composition of the winter range (McGillis, J.W. 1977. unpublished JOURNAL OF RANGE MANAGEMENT 38(1), January 1985 77 This content downloaded from 207.46. 13.59 on Mon, 13 Jun 2016 06:24:58 UTC All use subject to http://about.jstor. org/terms report) and the uniform grazing pattern of undisturbed wapiti (Morgantini and Hudson 1979). Willow samples were collected along the edge of the open range and were limited to current annual growth. Crude protein (CP) was assessed using the macro-Kjeldahl method (AOAC 1965). In vitro digestible dry matter (IVDDM) was determined following Tilley and Terry (1963) and Minson and McLeod (1972). The technique was modified by placing vials with forage samples and rumen inoculum in an incubation room maintained at 380C. Constant stirring was achieved with a flask shaker (160 rpm). Monthly samples were combined into one composite sample on which one IVDDM trial was conducted in triplicate. Rumen inoculum was obtained from a fistulated wapiti steer maintained on a diet consisting of a pelleted aspen-barley concentrate, chopped alfalfa, and browse. The animal had access to tame grass pasture ad libitum. Results and Discussion The contribution of major plant groups to the diet of wapiti during mid-winter hunts is compared with results before and after hunting in Table 1. During the winter of 1976-77, consumption of Table 1. Diets of wapiti during hunting (January 1977 and January and February 1978) and non-hunting periods (February and March 1977, December 1977 and March 1978). Percentage fecal composition. Hunting periods Non-hunting periods