The Fish and Wildlife Service is proposing to delist grizzlies from the protection of the Endangered Species Act in the Greater Yellowstone Ecosystem. The basic rationale for delisting is that the geographical distribution of bears has increased, particularly in areas south and east of Yellowstone Park, as well as population growth.

But there is a debate about whether this is enough to justify delisting and more worrisome, is whether the bear’s continued population growth is really ensured.

At best, there may be 700 grizzlies in the entire Greater Yellowstone Ecosystem. While this may seem like a large number, consider that grizzly are a tournament species. That is, a few large, dominant males, do the bulk of all breeding—hence reducing the overall genetic diversity in the population.

Many geneticists believe a viable population of 2500-5000 bears is necessary for the long-term survival of the species. This can only be accomplished if the Yellowstone bears numbers increase and eventually connected to other bear populations further north as part of a larger metapopulation.

There has been increasing mortality of female grizzlies in recent years for reasons that may be related to climate change—to be discussed in a minute. But higher mortality of females is critical since they are the source of new bears in the population.

The major argument against delisting has to do with a significant decline in Yellowstone grizzly food sources.

Whitebark pine, which has nutritious seeds, and which bears, particularly female bears, relied upon, have declined significantly due to bark beetles. The increase in bark beetle mortality in whitebark pine is attributed to global warming. As temperatures continue to rise we can only imagine even greater mortality in whitebark pine populations and loss of a major food source for grizzlies.

A second loss has been cutthroat trout. Bears used to feed upon spawning trout in tributaries to Yellowstone Lake, much as coastal brown bear feed on salmon. Lake trout which prey upon cutthroat were introduced into Yellowstone Lake and caused a major decline in cutthroat trout populations to the point where few to no bears feed on spawning trout any longer.

A third loss is meat. In the past, elk numbers were higher, and many elk died in winter due to starvation. This provided bears, particularly,  females with cubs, a ready source of highly nutritious food in spring after they left their winter den.

A fourth major source of food is army cutworm moth larvae. The moths feed on alpine flowers and lay their eggs in high rock basins. With global warming, tundra habitat is expected to shrink which may significantly reduce this food source, or alternatively, farmers may use more potent pesticides to reduce moth populations. In any event, this other pillar of grizzly food resources may decline as well.

One consequence of these changes in food resources has been greater conflicts with humans. Female bears who no longer can subsist on whitebark pine seeds are now driven to relying more on meat. But this forces them to seek out cattle or find gut piles left by hunters. Both activities put them more in harm’s way.

The continued culling of bison in Yellowstone Park also threatens grizzlies. Like elk, higher bison populations result in greater winter mortality. Winter-weakened bison or carrion resulting from winter kill are increasingly important food for bears, particularly at a time of year when other food resources are limited. Finding the carcass of a dead bison upon existing the winter den is like winning the lottery for a female with cubs. But the on-going bison slaughter is literally taking food right out of the mouth of bears, particularly, females.

Most current mortality of bears is occurring on the fringes of its occupied habitat. But these are exactly the bears we need to ensure connectivity to other grizzly populations, as well as for population expansion.

Finally given the long time to maturity combined low birth rate of grizzlies, bears are particularly vulnerable to population declines which might not be immediately apparent.

Given all these factors, it is disingenuous for the Fish and Wildlife Service and the state wildlife agencies in Montana and Wyoming to suggest that bears can safely be delisted Delisting would inevitability result in greater habitat losses and destruction. It’s time for the FWS to slow down. Let’s wait another 10 or 15 years and then revisit the grizzly delisting issue. Now is not the time to jeopardize the bear’s future.

 
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About The Author

George Wuerthner

George Wuerthner is an ecologist and former hunting guide with a degree in wildlife biology

7 Responses to Too early to delist GYE grizzlies

  1. avatar Bob Brister says:

    Until state governments demonstrate the inclination, capacity, and political will to manage carnivores in a humane and ecologically responsible manner, grizzlies and wolves should remain listed.

    • Thank you! The operative word is humane and their is none being practiced when it comes to any of the wild things left today. In Wyoming, killing wolf cubs in their den? Why is this ok? It’s cruel, cowardly and just totally wrong!

  2. avatar Immer Treue says:

    OK, I’ll play devils advocate with number three. Less meat, fewer elk… while climate may make some difference, the major player in the elk numbers is wolves. That said, there exists more scavenging opportunities on kill sites.

    The bison slaughter is difficult to wrap one’s mind around.

    • avatar Ida Lupine says:

      “Finding the carcass of a dead bison upon existing the winter den is like winning the lottery for a female with cubs. But the on-going bison slaughter is literally taking food right out of the mouth of bears, particularly, females.”

      I should think it would be the same for wolves, would it not? (See links) They don’t eat elk solely, do they. Here again, killing bison to appease ranchers for a non-existent disease threat is contrary to nature, and must compound every problem, including depredations.

      There’s no sense trying to blame wolves for every problem. Are human hunters not in the equation for loss of elk, or are all the elk commandeered for humans first?

      Yellowstone Wolves Eating More Bison (2014)

      New Research Shows Wolves Pick Their Prey Based on Pack Size (2014)

      • Delisting any wildlife is their death knell. The Fish and Wildlife, Wildlife Services, state and local wildlife people — none of them care about the wild things. It is their job to protect them and see that they continue to thrive but they don’t. Wyoming and Montana wildlife officials are cowards and don’t care!

  3. avatar Ida Lupine says:

    Sorry, the first link doesn’t seem to work:

    Yellowstone Wolves Eating More Bison 2014)

    From the report:

    “Out of the 255 animals that wolves killed and that were detected by the Wolf Project staff, 159 were elk (62 percent) while 32 were bison (13 percent). That’s the highest proportion of bison kills recorded since wolf monitoring began. The majority of the bison killed (17) were calves.”

    “Wolves are opportunistic feeders. The park staff detected one bighorn sheep, two Canada geese, four pronghorns, one grizzly bear cub and a coyote among the prey animals on the wolves’ diet.”

    Isn’t that desirable?

    And sad:

    “The park’s wolves are some of the most popular and hated animals in the West. Because of where they live, they are also some of the most studied wolves in U.S. history. The Wolf Project releases annual reports that are always two years behind the calendar year.”

    Thanks, George for this article. I’m very worried that the bears are not nearly ready to be delisted.

  4. The problem is that the officials in these states don’t care about the wildlife! They don’t have enough to do and so they spend their time tracking down and killing the wolves, bears, and anything else they find! Just take Wildlife Services. No one has ever heard of them and they kill more birds and animals than any other group. They operate under the Dept. of Agriculture. Cowards all!!!

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