Why monitor the bison?
The House Rock bison herd on the Kaibab Plateau that migrated onto the North Rim of Grand Canyon National Park has adapted to various habitats; grazing and wallowing in park meadows, stampeding through dense forests, and occasionally venturing along the rim of the canyon. Concerns of ecological impacts and effects to archeological sites have increased over the years as these bison have begun to congregate around natural water sources and change their migration behaviors to stay within park boundaries for longer periods throughout the year. Park researchers and collaborators have been monitoring the impacts of this herd on the natural and cultural resources of the North Rim and are establishing a feasible reduction plan.
What do the studies show?
Population Size and Migration:
Aerial surveys with collaborating agencies have shown that this herd is steadily increasing and is currently estimated at a size of 400-600 animals, which has the potential to grow to an estimated 1,200-1,500 individuals within the next 10 years. GPS tracking of individual bison has resulted in the conclusion that these animals have changed their migration patterns between House Rock Valley Wildlife Area (U.S. Forest Service property designated for bison management) and Grand Canyon National Park and they have not returned to House Rock Valley since 2009, staying almost entirely within park boundaries.