Twice as Many Grizzlies As Thought! Cheap Hair Collection Technique for Counting Bears Yields Larger Population Estimates
Photo via Alan Vernon. via Flickr CC
The high tech way of monitoring Montana's grizzly bear populations is proving to be old fashioned. Instead of expensive radio collars and difficult-to-maintain traps, researchers are turning to simpler, cheaper methods - picking grizzly hairs off trees. Turns out, the hair that grizzlies leave behind when they rub up against tree trunks and branches works as a genetic name tag, allowing researchers to count bears and track trends in the populations. It also turns out, that the new method is showing there are about 2.5 times more grizzlies than thought, which brings into question its status as endangered.Typically, putting a radio collar on a bear is not an easy or cheap task, nor is setting up traps, which the bears can get savvy to and so need to be maintained and moved around constantly. So instead, U.S. Geological Survey research scientist Katherine Kendall has pushed for a new method of collecting hair found on trees that grizzlies rub up against.
"The great thing about bear rubs is you aren't asking the bear to do anything it's not normally doing. They're just rubbing all the time. You get very precise estimates of trends. That's difficult to do with bears," stated Kendall.
The Washington Post reports that by combining results from Kendall's study with genetic samples collected from traps, scientists estimate that there are around 765 grizzlies in the Northern Continental Divide Ecosystem, which is around 2.5 times more than the initial estimate. That gets local businesses excited that perhaps Montana's grizzlies might be able to soon come off the endangered species list - especially lumber and forest managers who have bumped up against the protections put in place for the bears like road closures and logging restrictions.
According to the Washington Post, all grizzlies south of Canada have been listed as threatened since 1975. Yellowstone's grizzlies were delisted in 2007, but after a challenge to the decision, they were placed back on. Now the new method of monitoring bear rubs from nearly 5,000 trees between 2009 and 2011 just might give a more accurate look at the status of grizzlies in North America, so that the best decisions can be made. Scientists can monitor 10 times as many bears through this cheaper process, and the data appears to be more accurate.
More bears is, of course, great news but that doesn't mean they're necessarily ready to roll off the endangered species list. Grizzlies are certainly struggling against some big odds, from climate change, to a lack of food as salmon populations decline, to just plain old too many people on their turf. They need what protections they can get.
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