PARENT SESSION
Oral Session #48: Spatial patterns, spatial processes. Presiding: D. Deutschman.
Wednesday, August 8, 2001. 1:00 PM to 5:00 PM. Madison Ballroom C.
Habitat utilization shifts by bison in Yellowstone National Park .
JERDE, CHRISTOPHER1, TAPER, MARK1, MEAGHER, MARY1, 1
ABSTRACT- From 1970 to 1997, 151 flights were taken in a fixed wing aircraft to collect data on numbers, locations, and group sizes of Yellowstone National Park (YNP) bison. This population represents the only continuously wild and free ranging bison in the United States. Previous research into the developed data set included analysis of population dynamics and spatial dispersion. This study focused on using the data locations to investigate bison habitat use spatially and temporally. Ten different habitat types -- sedge meadow, upland, geothermal, trees, sub-alpine, creek/river, road, willows, 1988 forest burn, and elk/cattle feed-grounds -- were associated with bison observations. Until 1982, both bison density and the number of bison observed in sedge meadows gradually increased. From 1982 until the end of the study in 1997, YNP bison expanded their range while maintaining a constant density. Bison numbers in sedge meadows became constant and bison numbers in upland areas increased. Further analysis also demonstrates, after 1982, an increase in alternative habitat use. These results demonstrate a shift in the habitat use by YNP bison. Implications of this shift could have significant consequences on bison habitat quality, YNP bison carrying capacity, and range expansion by bison outside of park boundaries.
KEY WORDS: yellowstone, bison, habitat, Bison bison