Addressing the controversial topic of the Yellowstone grizzly bear’s status on the endangered species list, grizzly bear expert David Mattson of the USGS and visiting faculty at Yale University School of Forestry and Environmental Studies delivered a talk to a crowded Hager Auditorium at the Museum of the Rockies on Thursday, April 7. His lecture was entitled “The Changing World of Greater Yellowstone’s Grizzly Bears,” and was given in response to a recent announcement from the U.S. Fish and Wildlife head, Dan Ash, that Fish and Wildlife would like to take the Yellowstone grizzly bear off the endangered species list.
Mattson was invited to lecture at the Museum of the Rockies by the Gallatin Wildlife Association, the Center for Biological Diversity and the Sierra Club. After studying the ecology of grizzly bears for 30 years, Mattson has been able to track and evaluate populations of bears to determine where they are living, what they are eating and the effect that changing environment and habitats have on the bears.
In 1975, when the Yellowstone grizzly bear was added to the endangered species list, there were an estimated 136 bears within the Greater Yellowstone Area. Today, there are an estimated 700 bears residing in the area. Although these numbers seem to suggest that the grizzly bear population has recovered, Mattson believes that the current estimate is too high due to increased efforts in grizzly bear monitoring, and that the bears are still at risk from a changing climate and habitat.
Mattson explained to the crowd that Yellowstone grizzlies traditionally have a diet high in pine seed and trout consumption. Backing up his statements with trend graphs, Mattson showed that as pines have been less available to bears due to climate change and fires, and trout populations have been in decline, Yellowstone grizzly bears have branched out to search for new food sources, primarily moths that live on the mountain slopes. Bears turn over the slickrock exposing the moths, and a hungry bear can eat up to 40,000 moths a day. The grizzlies are also eating more large game than they have eaten historically.
As the bears are spreading out to find alternative food sources, their population density is actually decreasing. “This paints a picture of a population in trouble,” Mattson said. Because bears feeding on moths on an open mountain side are more easy to spot, Mattson believes that bear populations are being over recorded and that the population as a whole is not as healthy as it appears. He argued that Fish and Wildlife should wait five more years to see if the bear population estimates are accurate and reflect a healthy population before taking them off the endangered species list.
If Yellowstone grizzly bears are taken off the endangered species list, and therefore open for sport hunting, Mattson estimates that only two females and perhaps 12 males would able to be hunted each year. He does not see any economic advantage that is worth risking all the policy and respect for the grizzly bear that has allowed the population to recover as much as it has. Mattson pleaded to the crowd, “This is not a time to be taking risks, but a time to be cautious.” According to Mattson, 95 percent of the Greater Yellowstone grizzly bears deaths can be directly attributed to human causes. He believes this number will only go up if the Yellowstone grizzly bear is taken off the endangered species list.
Those who are interested in the Yellowstone grizzly bear and what it means for them to be taken off the endangered species list are encouraged to attend an informational open house meeting and public hearing on Tuesday, April 12 at the Holiday Inn in Bozeman. The informational open house meeting is from 2-4 p.m. and the public hearing is from 5-8 p.m.
Story by Dave Biegel