Abstract 98 – An analysis of American black bear (Ursus americanus) spring diet to assess predation risk of neonate wood bison (Bison bison athabascae)

Molly Sharp, Scott Nielsen, Mark Edwards

American black bears (Ursus americanus) are generalist omnivores, with a diet primarily
composed of vegetation and some animal matter. Black bears are noted as potential predators
for a number of ungulate species, particularly neonates due to their limited mobility. In this
study, we analyzed the diet of black bears occupying the late spring and early summer range of
a small, threatened wood bison (Bison bison athabascae) herd in the Ronald Lake area of
northeast Alberta to determine the predation risk to neonate bison. In the spring of each year,
the Ronald Lake bison herd (RLBH) migrates to an upland meadow near the base of the Birch
Mountains. During this time, bison calves are dependent on cows and vulnerable to predation.
Camera traps have shown that black bear activity in the meadow increases when bison are
present in the spring, which may suggest that black bears are preying on neonate bison. We
used scat analysis and DNA metabarcoding to describe black bear spring diet and quantify
consumption rates of bison. We hypothesized that herbaceous plants would dominate black
bear diet in the spring and berries would dominate at the start of summer, with supplemental
protein achieved through predation or scavenging. Black bear diet was predominantly
composed of herbaceous and fruiting plants. Bison DNA was found in 1 of 79 scat samples. Our
preliminary results suggest that neonate bison are not an important component of black bear
spring diet and that predation risk to the Ronald Lake bison herd from black bears is likely to be
minimal.