New research: Wolves indirectly help bears by promoting berry growth

A new study by Dr. Bill Ripple and his colleagues, “Trophic cascades from wolves to grizzly bears in Yellowstone” in the Journal of Animal Ecology suggests a second way the return of wolves has helped the Yellowstone grizzly bears.

Grizzlies have thrived in Yellowstone Park in recent years despite the destruction of the cutthroat trout fishery, and the death of most of the thought-to-be vital whitebark pine stands with their nutritious nuts. The reason wolves helped the bears was them taking down more elk than the grizzlies ever could. Some of the wolf-killed elk were promptly stolen by the bears. The result was a big boost in nutrition for the bears. Now a second positive effect of wolves for bears is being explored by a scientific team from Oregon State and Washington State Universities.

The reduction of elk numbers by wolves and the creation of a “landscape of fear” for the remaining elk has kept the remaining elk moving. In their wake berries have begun to proliferate.  Everyone knows bears love berries, but they are not very abundant in most of Yellowstone Park.  One of the major reasons is browsing of the bushes by deer, and even more by elk. Then there is trampling from the bison herds. Wolves primarily target the elk, but the less numerous deer too, and bison are harassed and sometimes killed by wolves.

The researchers found that the proportion of berries in grizzly bear scat in August (berry month)  has almost doubled over the years since wolves were returned. While July sees  fewer berries than August, the number of berries found in bear droppings in July increased about 7 times over what used to be in July.

Outside the Park, where the super-abundant, but non-native grazing animal lives, Bos primigenius (cow), berries are reduced by their grazing and trampling. The report suggests the option of retiring cattle allotments in the grizzly bear recovery zone next to Yellowstone. This will increase berry production there.

Thinking about the suggestions of the study, I note that cattle and elk compete almost directly for forage.  Estimates are 90% overlap between the food preferences of the two animals. So cleaning out the cattle in the area’s public lands would also benefit elk — more grass and forbs to eat.

This study’s preliminary conclusions are important because the grizzly bear is slated for delisting from the threatened species list in the Greater Yellowstone recovery area. The boundaries of what will be the “Primary Grizzly Bear Conservation” area are thought by many to be too small to support the recovery grizzly population — not enough food.  Critics say the bears need to be allowed to range more widely to secure what they need to eat. However, if the land inside the primary grizzly bear conservation area was more productive of bear food, its relatively small size would be more adequate.



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  1. Larry Zuckerman Avatar
    Larry Zuckerman

    Another stretch from reading the original research paper might actually reduce grizzly bear-human-cattle conflicts outside the park’s boundary. When I lived in Cody and worked for WYG&F I saw more than 14 griz outside the park in about a 2 week period, while I was sampling fish in the Absarokas. I also ran into the “bad bear” biologists that were trying adversion behavior mod on the bad bears to teach them that messing with sloppy elk camps and improperly stored campers’ food wasn’t such a slick idea. This was a year of failure of whitebark pine nuts and a late frost that nailed the berry crop – the bears were hungry and were doing what they needed to do, before heading to the dens hopefully fattened up for the winter and giving birth to their cubs. They just did not care about people or being seen – not like my previous experiences where the bears did everything they could do to avoid people.

    So…. manage for berry production including a more natural mosaic of wildfires instead of FS policies on fire suppression and with the wolves given a solid buffer in ID, WY and MT from hunting, trapping, and snaring, perhaps they will get what they need from berries to convert to winter fat instead of turning to “slow elk” (i.e., fattened cattle and calves).

    what do you think? of course, getting rid of the temptations by removing the surrounding cattle is a great start. Think of the money spent on collaring, tracking, transporting, and killing grizzly bears and wolves as unwanted predators and consider converting that money into one-time buyouts of grazing permits and perhaps conservation easements on private ranch lands in the GYE.

  2. lynnstarrs Avatar

    Most of the ranches are not economically sustainable without the public grazing lands. So retire the allotments and sell the private lands for ski resorts, ranchettes, and second homes for the wealthy. The owners can enjoy living near the park and watching the bears.

    1. Ralph Maughan Avatar
      Ralph Maughan

      Folks should be aware that the National Wildlife Federation has worked the grazing permit holders and the Forest Service to retire about 200,000 acres of grazing allotments in the Greater Yellowstone.

      These were voluntary, mostly paid for retirements of the allotments

      1. rork Avatar

        I am wildly enthusiastic about such attacks being the way forward in many places.
        Near me various conservancies, as well as taxpayers who voted to tax themselves, are buying up land and development rights.

    2. mikepost Avatar

      Lynnstarrs, much of this private land serves as wintering ground for elk, deer and antelope. Conversion to 20 acre ranchettes and 2nd homes will be just as detrimental, if in a different way, than the ranching activities. There are few wild critters that benefit from residential development.

      1. JB Avatar


        I’m not entirely convinced that this is so–it really depends upon the home’s (and other buildings) overall footprint on the land. Certainly RM elk have shown an ability to utilize private lands to acquire food (Estes Park, anyone?). The question is: to what degree is the gain in biomass available to wild ungulates by removing cattle offset by the loss of some of the land to homes, driveways, garages, and roads. I would argue that the answer to that question depends, in part, upon the size of the lots, how lands are developed, and a variety of other factors.

        1. WM Avatar

          Indeed, some private developed land for wintering wildlife is questionable (and for other seasons too). Especially no barbed wire, no dogs, no gardens and no golf courses, no schools, no parks (wooded is not good), no play fields and no orchards, no roads, no garbage dumps.

          And for the other seasons, no people around during the rut, no people around if cow elk or moose are calving. No readily available indvidiual garbage sources for bears, no chickens for foxes, coyotes or skunks. No wooded fringes adjacent to shopping malls (cougar dead in Lewiston). No corn fields (grizzlies dead at hands of Hutterites).

          Maybe no livestock of any kind (no pets), and no sanctuary for natural prey species to draw in wolves, in any season. It mostly ends badly for wildlife when these conditions/opportunities are present.

          Now the occasional alfalfa, corn or wheat field, and maybe a rancher’s hay stack all on large tracts in winter without people might not be so bad. But do be careful those Hutterites who don’t like grizzlies in their corn.

          1. Ida Lupine Avatar
            Ida Lupine

            I don’t see how it could ever work out better than ranching, roads, schools, children (at bus stops), traffic, recreation, garbage and small animals to draw in wildlife. Wait till these people start complaining about wildlife that becomes too close for comfort. More development of our wild lands is not a good idea at all. IMO, only a rare breed of wealthy could have private land for wildlife without wanting to exploit it in some way. And where would our beef be raised for those who eat it? We have more than 300 million people and growing in our country alone.

            1. rork Avatar

              Oh no, the price of cow meat might rise. We are doomed.

              1. Ida Lupine Avatar
                Ida Lupine

                I fail to see the logic in replacing a cattle ranch with a ski resort.

                1. Richie G. Avatar
                  Richie G.

                  I agree Ida one thing for money then another thing for money. Their is one in Montana and people do not like it much they rather go to Utah the snow is softer.

              2. SaveBears Avatar

                Richie, our snow is great in Montana, fine Rocky Mtn Champagne

                1. Richie G. Avatar
                  Richie G.

                  SB I heard that from a few skiers did not make it up. You have a ski resort up in Montana I heard about it and ask a few skiers who ski a lot, I ski but not a lot I been to Colorado and that is the most out west. But people who I’ve talked to like Utah the best, they say the snow is softer easier to turn on. More ice where you are, not putting down Montana.

              3. SaveBears Avatar

                Well Richie,

                I don’t know where they skied, of course I don’t ski but my wife and grandkids do and they love it up here, in fact our ski resort here NW Montana has made it into the top 10 as named by Ski Magazine many times.

                1. Richie G. Avatar
                  Richie G.

                  SB; All I know is what skiers have told me not from the same group different and they like Utah the best. Even a doctor who ski’s a lot moved to Utah, and he likes the snow as I said they said it’s the softest, even out of Colorado. So this is what I’ve heard again, just what people have told me and I bet on that list Utah is in at least the top five.

              4. save bears Avatar
                save bears

                Honestly Richie it really does not matter, everybody has there favorites

                1. Richard G. Avatar
                  Richard G.

                  I agree we all have favorites but mine are wolves being I had ten dogs throughout my lifetime all got people food .All my dogs got best of care at all cost !!!!! Better late than never !!!!

        2. Richie G. Avatar
          Richie G.

          Right JB if they are small cabins hidden in the woods and people like it this way I think it could work. But not rows and rows of houses, anyway the weather is too cold for that kind of development.

  3. rob santa Avatar
    rob santa

    Agreed on the one-time buyout of cattle grazing leases on public land (sheep too). Give our native species the greatest possible natural range and restore our natural resources!

  4. BobMc Avatar

    Temporospatial distributions of elk, mule deer, and cattle: resource partitioning and competitive displacement states in the summary:

    The authors conclude that cattle compete with elk and mule deer, by forcing them to select different habitat types and vegetation.

    This is another reason to get cows off the landscape, they essentially increase the total area being grazed, as well as the diversity of flora.

  5. Louise Kane Avatar

    Ralph can you post a link to the full paper?

    1. Salle Avatar


      It might not be available for free online. Many of the refereed journals and academic studies often require a subscription to EBSCO (a rather pricey deal there) or the actual journal if they have a web site for such publications. At least that’s what I’ve found in many cases. A copyright thing I’m guessing.

      It wold be nice if we could have easy access to that sort of thing though, I’d like to read it too.

    2. Ralph Maughan Avatar
      Ralph Maughan


      Salle is right. It is not available to the public except for a charge. However, the abstract is provided, giving a more precise summary of the findings. See

      1. Louise Kane Avatar

        a very kind person who posts here sent me the article. Thank you

        1. Ralph Maughan Avatar
          Ralph Maughan

          Me too, thanks

  6. Joseph C. Allen Avatar
    Joseph C. Allen

    I have been a long time follower of Bill Ripple’s and Robert Beschta’s research. I have included a link to theirs and others on the Oregon State University website. Although the particular article is not present there (in the process of peer review), others of great interest are found there.

  7. Richie G. Avatar
    Richie G.

    I s this research really going to help the wildlife as a whole, not just wolves and bears but the entire eco system. Will the new Secretary follow the researchers findings. Obama gave money for the rino and the elephant trade, will he influence the wildlife of his own country. Nothing against illegal elephant and Rino trade of their ivory but will he help us now.

  8. Ida Lupine Avatar
    Ida Lupine

    This is wonderful news.

  9. Richie G. Avatar
    Richie G.

    P.S. Nice article Ralph for bringing it to our attention
    thank you

  10. Bob Ostler Avatar
    Bob Ostler

    Research Papers: My local university will give me a FREE day pass to use their computers and view these sorts of articles. I have found the people at the library’s “genius” desk very helpful with these sorts of things.

    Ralph, what is the status of buying up grazing rights and retiring them. I seem to remember that there was some question of the legality of doing this.

    1. Ralph Maughan Avatar
      Ralph Maughan

      Bob, you are right about the legality of buying public land grazing leases.

      Nevertheless, if the managing agency cooperates and amends the Forest Plan to close the area to grazing, thus eliminating the grazing allotment, it can be done. It has been done in the instances I mentioned.

      I should add that the BLM or the Forest Service can close an area to further grazing with no compensation at all to the permittee for repeated violations, emergencies, or re-analysis in a revised management plan that finds the land “not suitable” for grazing.

      This doesn’t happen often.

      1. Rancher Bob Avatar
        Rancher Bob

        What happened to HR 2201 I see they think it now has a 1% chance of passing.

        1. Ralph Maughan Avatar
          Ralph Maughan

          Rancher Bob. It is not going to pass. Unfortunately you can say that about just about every bill in this Congress.

          At any rate, most important bills that are not annual appropriations or are trivial bills to name a federal building, etc., have to be introduced repeatedly from one Congress to the next. Success, if it ever comes, happens as members become familiar with it.

  11. Richie G. Avatar
    Richie G.

    When you say retire the land I hope that doesn’t mean to give this land to contractors who will build homes on this land. Here we go again somebody else has a game to make money. I hope this means small cabins for some people. Montana has under a million people so a few cabins can’t hurt I think? Still this land must be first for wildlife.

  12. Leslie Avatar

    One positive from all the beetle kill is forests are opening up and I’ve noticed a tremendous uptick in the chokecherry population around here. Also have seen an increase in Juneberry plants that were lacking before. This year will be a fantastic berry season with all the moisture we’ve had. Roses as well.

    But I have to wonder that berries don’t equal the fat content that pine nuts provide and bears so need in the fall.

    1. Rancher Bob Avatar
      Rancher Bob

      Interesting observations, your saying increased beetles=decreased live trees=more berries.
      Dr. Ripple findings are increased wolves=decreased elk=increased berries.
      So if you had to make a educated guess how much of what your seeing is because of smaller elk populations and how much of what Dr. Ripple is seeing maybe due to beetle kill?
      Around here the frost around flower time has the largest effect on production of berries.

      1. WM Avatar


        …or, due to beetle kill or FIRE and subsequent plant succession.

        I have not seen the paper, so don’t know whether Ripple/Bestcha have attempted to account for all potential factors affecting ecosystem changes over time. That, in past papers, has been a constant source of criticism of their work (Dr. Mech is one we have talked about here), including one of Ripple’s former students and wolf advocate Cristina Eisenberg, who has a slightly different twist on trophic cascade, from my recollection.

        It is always good to view these things with a critical eye until verified by other researchers. Afterall, science is self-correcting.

        1. WM Avatar

          Sorry, forgot to connect the dots. Service berry (Amelanchior alnifolia), the primary seed berry these guys studied in grizzly poop is an ecological succession plant which fills in after things like fire or bug kills. So how does this all fit together to tell the story?

          1. Rancher Bob Avatar
            Rancher Bob

            I guess my problem with Yellowstone studies is that yes we get some insight as to how ecosystems work without human presents. Problem is the several billion humans on this rock. When do we get some studies that show how ecosystems react where humans and everything else live?
            Yellowstone was broken as a ecosystem and now is on the mend most that change was going to happen simply by reducing the number of elk, on matter what reduced their population, this way the wolf gets the credit. What if the elk population had been reduced by some disease just before reintroduction?

            1. Immer Treue Avatar
              Immer Treue

              “What ‘if’ the elk population had been reduced by some disease just before reintroduction.”

              And ‘if’ my Aunt had balls she’d be my uncle.

  13. Richie G. Avatar
    Richie G.

    You are correct that is what I have been trying to say sb
    it is just people’s opinion.

    1. save bears Avatar
      save bears

      Same thing I was saying

      1. Richie G. Avatar
        Richie G.

        We Agree sb


Dr. Ralph Maughan is professor emeritus of political science at Idaho State University. He was a Western Watersheds Project Board Member off and on for many years, and was also its President for several years. For a long time he produced Ralph Maughan’s Wolf Report. He was a founder of the Greater Yellowstone Coalition. He and Jackie Johnson Maughan wrote three editions of “Hiking Idaho.” He also wrote “Beyond the Tetons” and “Backpacking Wyoming’s Teton and Washakie Wilderness.” He created and is the administrator of The Wildlife News.

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Ralph Maughan