Two recently published studies suggest that the elk departing from Yellowstone National Park may be connected to a drop in cutthroat trout. According to the Missoulian, the answer lies in the dietary habits of the park’s bear population. Fewer spawning trout in the area caused a shift from a fishy diet to something involving more red meat: elk calves.
Arthur Middleton, lead author of a study published Wednesday in Proceedings of the Royal Society Biological Sciences, believes the change in diet have significantly impacted the park’s elk population. In Yellowstone bears have always been the most significant predators of elk calves, but now Middleton and fellow researchers are seeing a spike in the number of elk killed. Calf recruitment has gone down by 4 to 16 percent and overall elk growth decreased by 2 to 11 percent.
“It might be worth adding that we don’t think this is the answer to where the elk calves went, but it’s something we should think about with changes in bear diets and the change in elk calf numbers,” Middleton said.