Counting Bears

9 Jul

Editorial Board / New York Times

There is nothing simple about counting grizzly bears. But counting them accurately will help determine whether they remain on the endangered species list or are delisted. The Interior Department’s Fish and Wildlife Service says there are about 700 grizzlies in the greater Yellowstone ecosystem, more than the 500 it deems essential for a healthy population. But a new study in the journal Conservation Letters calls those numbers into question.

A count is a projection, based on assumptions about the reproductive and survival capacity of grizzlies. The agency assumes that the bears live until they are 30 years old and reproduce at constant rates all along. This is a mathematical convenience, not a biological observation. The study argues that the inaccuracy of previous counts means that biologists know less than they think and concludes that grizzly numbers appear to have increased simply because government biologists are working harder to count the bears.

For these reasons, one federal researcher has said that current estimates are “essentially worthless.” Some biologists argue that a total of 500 bears isn’t nearly enough to guarantee a genetically healthy population. Their natural habitat — high-elevation pine forest — has been devastated by the mountain pine beetle. This has resulted in more frequent contact with humans, which nearly always ends in dead bears.

With some species, the Fish and Wildlife Service has done a good job chronicling and aiding their recovery. But those species do not include top predators like the gray wolf and the grizzly bear. Fish and Wildlife needs to pay close attention to the criticisms of its bear count and bear management plan. It is hard to imagine how a species whose habitat has been devastated and whose numbers are uncertain could be removed from federal protection.

One Response to “Counting Bears”

  1. Buddy2Blogger July 9, 2013 at 9:23 pm #

    Reblogged this on Sherlockian's Blog.

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