A Barbed Wire Covered With Fuzz Will Let Study Know Which Bear It Was
Scientists are using a low-tech device to aid in a high-tech study they hope will provide information to help preserve grizzly bear populations in the lower 48 states.
Yellowstone Grizzly Foundation researchers Steve and Marilynn French and Oxford University geneticist Ryk Ward have started hanging strands of barbed wire in the Yellowstone area to snag hair from wild grizzlies.
The hair is to be used in a study of grizzly bear genetics the researchers hope will answer several pressing questions, including the number of grizzlies in the area and the population’s genetic diversity. The study will sample the DNA of individual bears.
The Frenches and Ward started the three-year study more than a week ago. Finding a way to attract the bears is the first problem, since they do not want to reward the bears with human-provided food and encourage them to return to the same spot.
Obtaining a sample from the same bear produces no additional evidence and costs $75 per sample for the genetics lab work.
“We want to develop an attractant that will make the bears come to the trap, that is lightweight, small and inexpensive and does not give the bears a food reward,” Steve French said. “So instead of putting a 2,000-pound carcass down, we’re trying to get a perfume that makes the bears come in to investigate food.”
The researchers also plan to find sample DNA from bear specimens in museums and other collections taken from the Yellowstone area. Such samples would help determine the historic genetic diversity, French said.
Biologists have expressed concern that grizzlies in Yellowstone, which essentially are isolated from other grizzlies, may not have enough diversity in their gene pool to ensure long-term survival. Reductions in overall genetic diversity are signs of inbreeding and a decline in fertility.
In the early 1800s, up to 100,000 grizzlies lived in North America west of the Mississippi River. By 1900, only small, scattered populations remained.
Grizzlies were listed as a threatened species in the lower 48 states in 1975 after the U.S. Fish and Wildlife Service estimated that fewer than 1,000 bears remained. Isolated populations of bears survive in northern Montana, Canada, Idaho, Washington and around Yellowstone Park.
Biologists would like to increase the diversity in the bears’ gene pool, possibly by creating corridors from Yellowstone to other bear populations or bringing bears from other ecosystems to the park area.
The Frenches and Ward also hope an analysis of grizzly DNA will give scientists a sound method of determining a minimum number of individual grizzlies in the Yellowstone area.