Stephen Hamilton

Estimating winter carrying capacity for bison in Wood Buffalo National Park

Bison (bison bison) in the Peace-Athabasca Delta (PAD) o f Wood Buffalo National Park have been fewer than the neighbouring Hay Camp since the late 1990s despite being greater in the 1970-80s. I compared the winter nutritional carrying capacity (K) o f the PAD to the Hay Camp, assuming varying snow depth and forage preferences, to determine whether K was restricting in the PAD. I sampled plant cover and biomass to estimate forage availability and quality within five vegetation types, and estimated K for the extent o f these types. The PAD had more biomass o f preferred species, Carex atherodes and Calamagrostis spp., than the Hay Camp, resulting in 4 to 12 times the K of the Hay Camp. I simulated the effect o f non-native plants on K assuming a 65% average reduction in preferred forage. Non-natives were more widespread and abundant in the PAD, but did not reduce K below that of Hay Camp.