Wild bison as ecological indicators of the effectiveness of management practices to increase forage quality on open rangeland

a b s t r a c t Habitat manipulations through the use of fire or mechanical treatments are often used to combat woody plant encroachment and increase foraging opportunities for wildlife and livestock. This creates spa- tial heterogeneity in habitat quality that large herbivores should respond to in ways predicted by ideal free distribution theory. We monitored free-ranging bison to test whether, (1) manipulated habitats offer higher quality forage than habitats in undisturbed rangeland, (2) bison respond through changes in herd composition or activity to differences in habitat quality, and (3) burned and mechanically treated habitats offer similar forage qualities. We found that habitat types burned ∼10 years ago continue to produce higher quality forage as evidenced by bison fecal N concentration (14.4 g kg−1 dry mass) than open (10.5 g kg −1 ), closed (10.6 g kg −1 ), or mechanically manipulated habitats (11.7 g kg −1 ). Bison herd