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The world’s top predators are in decline, and it’s hurting us too

Humans have an innate fear of large predators, and with good reason. Nobody wants to be a shark or a lion’s next meal. But new research in the journal Science shows that our inability to live with these…

Without tigers, our ecosystems will suffer. Flickr/kohlmann.sascha

Humans have an innate fear of large predators, and with good reason. Nobody wants to be a shark or a lion’s next meal.

But new research in the journal Science shows that our inability to live with these animals is putting their survival in great danger, and doing untold damage to the environment.

Through modifying the habitats of large predators or killing predators more directly, we are greatly compromising the ecosystems that they help to keep in balance — free of charge. In turn this environmental degradation creates many problems that have severe consequences for humans.

We ain’t lion, this predator stuff is a big deal. Flickr/Derek Keats

Top dogs (and cats) under threat

For the first time, a team of researchers from the United States, Australia, Italy, and Sweden, and led by Professor Bill Ripple at Oregon State University, have analysed the effects of threats such as habitat loss, human persecution and reduced prey on the world’s 31 largest mammalian carnivores.

The species studied include lions, tigers, African wild dogs, leopards, cheetahs, wolves, lynx, otters, bears, hyenas and dingoes. Together they span all continents except Antarctica.

Alarmingly, more than three quarters of the 31 large carnivores are in decline, and 17 species occupy less than half of their historical distributions. The Red Wolf in the southeastern United States is now found in less than 1% of its historical range, and the Ethiopian Wolf in just 2%.

Hotspots of carnivore decline are southeast Asia, southern and East Africa, and the Amazon, where several large carnivores are declining. And in the developed world there are now few places where large carnivores remain.

In Australia, dingoes help keep introduced predators at bay. Flickr/Ars Electronica

Aside from the intrinsic tragedy of losing any species, what should perhaps concern us even more is that we are only just beginning to understand and appreciate just how important large predators are to maintaining healthy ecosystems, and our dependence on the ecosystem services they deliver.

Ripple effect

Seven carnivore species in particular have been shown to have profound effects on the environment and cause what is known as “trophic cascades”. A trophic cascade is a ripple effect, where one species’ influence spreads through multiple levels of a food web.

Species for which this effect is most well-known are African lions, leopards, Eurasian lynx, cougars, gray wolves, sea otters and dingoes.

It’s hard being a VIP (very important predator). Flickr/Mike Baird

In Australia dingoes greatly reduce kangaroo and red fox numbers, which in turn reduces grazing of vegetation and predation of native animals, helping to conserve and protect biodiversity.

In coastal North America, sea otters keep sea urchin numbers in check, which helps maintain kelp forests and benefits other marine species dependent on this habitat. But in this case otters might also offer a defence against climate change, as healthy kelp forests can grow rapidly and store large amounts of carbon.

And in Africa, a decrease in lions and leopards has coincided with a dramatic increase in Olive Baboons, which threaten farm crops and livestock, and spread intestinal worms. Baboons even impact education, as children have to stay home to defend their farms from raids.

Without lions and leopards, there’s no telling what baboons will do. Flickr/JustinJensen

Clearly predators have far-reaching ecological, economic and social benefits that are grossly underappreciated. There is no doubt predators pose challenges too, such as wolves attacking livestock. But education and new management practices offer ways forward. For instance, we could use guardian animals to protect livestock from predators.

Together we call on governments to end policies and management practices that are responsible for the ongoing persecution and loss of predators from our planet. Western Australia’s new shark plan is an example of management that fails to account for the science of big predators. Instead we need an international initiative that aims to conserve large predators and promote their coexistence with people.

Join the conversation

34 Comments sorted by

  1. Mike Swinbourne

    logged in via Facebook

    Thanks Euan - I would like to suggest this is one of the most important issues facing us today, because of the effects the loss of apex predators have on the rest of the ecosystem.

    Small point, but I am surprised you didn't mention the case of wolves in Yellowstone NP - one of the best examples of trophic cascades around. Because of examples like this, we interfere in these processes at our peril, as we really have little concept of what will happen once an apex predator has been removed or reduced. Which is exactly why Colin Barnett should be castigated long and hard over the plans to remove great whites.

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  2. Alice Kelly
    Alice Kelly is a Friend of The Conversation.

    sole parent

    There is also the possibility that our behaviour could have encouraged sharks to change their feeding behaviour.
    Shark nets, (which sharks swim under), catch other animals and have become feeding stations for them.
    Tuna farms in the ocean attract them
    Shark watching tours encourage them to come to a boat and be fed.
    Fill a wet-suit with meat to get "footage" of a surfer being mauled/eaten.
    Fishing boats around much of Australia provide by-catch and offal, and is an opportunity for a feed.
    There is also the fact that there are less and less of many species, and there is no reason why grey nurse sharks will be killed during the latest proposal by Colin Barnett. Also it's simply putting in another feeding station.
    If they want to swim at Cottesloe Beach, build an ocean pool, or, swim in the ocean. White pointers are endangered for a reason, adding to this problem is stupid.

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  3. Dustin Welbourne

    PhD Candidate in Biogeography + Science Communicator at UNSW Australia

    One problem with this article... too short. I know this is not your fault Euan but instead that of the word count gods, but hey, thems the breaks.

    However, it would have been great to have you unpack this issue in more detail.

    (The debate about the underpinning philosophy of top down v. bottom up can be saved for twitter.)

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  4. Russell Hamilton

    Librarian

    "Species for which this effect is most well-known are African lions, leopards, Eurasian lynx, cougars, gray wolves, sea otters and dingoes ... Western Australia’s new shark plan is an example of management that fails to account for the science of big predators"

    This appears to be citing evidence about some animals and then applying it to others - are there relevant studies about sharks? Couldn't it be the case that the most significant apex marine predators are humans, who now take so much life out of the ocean that ecological effects of what great white sharks might do is irrelevant ?

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    1. Russell Hamilton

      Librarian

      In reply to Nick Kermode

      Hi Nick,

      I'm not sure that study applies - it compares a fished reef to one where sharks have been fished, but it doesn't look at the effect of large scale commercial fishing on either, since it doesn't happen.

      Also if we're talking about great white sharks - don't they swim over vast distances, over to South Africa? South America? I'm guessing that we don't know what ecological effects removing a few of those sharks would have, but it could be negligible compared to what our fishing does? Anyway we'll see how many are actually caught on these few hooks off a few beaches.

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    2. Nick Kermode

      logged in via email @hotmail.com

      In reply to Russell Hamilton

      Doesn't apply? Sorry you have lost me there Russell. Did you read both papers I suggested?
      Those studies prove this article applies to sharks perfectly, answering the point you raised.
      You say "but it doesn't look at the effect of large scale commercial fishing on either, since it doesn't happen." Read Myers 2007 like I suggested if you want to learn some more, it would save you asking "but it could be negligible compared to what our fishing does?".
      Let me help....it says that studies have…

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    3. Russell Hamilton

      Librarian

      In reply to Nick Kermode

      I read the Conversation piece you linked to, and as much of the related article as I could understand, and I questioned that study's relevance to my question because the areas studied weren't subject to commercial fishing. I was asking is the effect of our huge world wide industrial fishing making the ecological impact of great white sharks, as they roam around the world, negligible.

      Since you didn't link to the Myers article I assumed it was only accessible by people with some university affiliation. But I have Googled the article, I think, and it's interesting and relevant, but it's about the effects of the 'functional elimination' of many types of sharks whereas I'm asking about just the great white since that's what all the fuss is about. Let's see how many are caught once the hooks are deployed.

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    4. Nick Kermode

      logged in via email @hotmail.com

      In reply to Russell Hamilton

      Natal had just about the best record for catching great whites with drum lines. The percentage is about 2.7 of the total catch. Of that tiny percentage only a tiny percentage were over 3m with the biggest being 3.48m. The average was just over 2m. Other places around the world have a worse record. Your comment seems to suggest you think we can target "just" great whites, when in fact by setting these drum lines we need to consider the effect it will have on several apex predators. Removing apex predators from other ecosystems and other areas of the ocean has proven universally detrimental and does not support your "lets just sit back and see how it goes" attitude. As this article shows, we know how it goes.

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    5. Russell Hamilton

      Librarian

      In reply to Nick Kermode

      "Your comment seems to suggest you think we can target "just" great whites". No, I'm just assuming the others aren't as much worry. It's the Great Whites that are threatened, aren't they?

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    6. Nick Kermode

      logged in via email @hotmail.com

      In reply to Russell Hamilton

      No Russell you assume wrong.

      Threatened in WA we have

      Great White...Totally Protected
      Tiger Shark...Totally Protected
      Bull Shark... Totally Protected
      Lemon Shark...Totally Protected
      Bronze Whaler...Totally Protected
      Grey Nurse...Specially Protected

      and more.......

      From WA Dept. of Fisheries: "All sharks and rays are now commercially protected"

      Here are a couple of other direct quotes from WA fisheries...

      "Large sharks are often the upper level or top predators within an ecosystem…

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  5. Angus Martin

    Zoologist

    Dustin Welbourne: the original paper in Science, of which this is a precis, is packed with detail and well worth reading if you can get access to it.

    Just in passing: could we please be spared the idiotically jokey, inaccurate, tabloid-quality photo captions that mar this interesting and important contribution.

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    1. Paul Rogers

      Manager

      In reply to Angus Martin

      Yes, regarding the captions, very poor form indeed for a serious subject.

      The Conversation: please don't give this job to the work experience person.

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  6. Keith Bradby, Director, Gondwana Link

    Director

    Great article Euan, many thanks. And the captions at least floated for me the concept of recognising apex predators as VIPs (Very Important Predators) which I think is a useful popular context to place them in (the term 'Apex Predator' doesn't work too well at my drinking holes). Mind you, I could be biased, living in WA where two critically important VIPs (great Whites and dingoes) are both persecuted through ridiculous taxpayer funded program's that defy the best science around.

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  7. Jim Inglis

    retired

    Apex predators do what they are supposed to do in their naturally evolved environment but to claim that the introduced placental dingo assists with the preservation of our threatened native marsupials is a ridiculous claim.

    Please see my comments in more detail here:

    http://theconversation.com/will-we-hunt-dingoes-to-the-brink-like-the-tasmanian-tiger-19982

    That photo of a dingo scavenging fish remains is telling you it has eaten pretty much all available wildlife on Fraser Island, is now…

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    1. Jim Inglis

      retired

      In reply to Euan Ritchie

      Thanks Euan, I have looked at it before and I wholeheartedly agree with the concept that top predators regulate biodiversity and have positive outcomes in a natural environment.

      But what we have in Australia is several millennia from a natural environment and that is the first thing that needs to be acknowledged.

      Following that we need to acknowledge that "a suite of conceptual models" is not likely to give us our answer due to the limitless number of combinations of animals and habitat landscape…

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  8. Kenneth Mazzarol
    Kenneth Mazzarol is a Friend of The Conversation.

    Retired

    I think it is a great pity that the actual top predator, human beings, are not in decline. We are also the top parasites, living off the host, Mother Earth, giving little in return. Shitting in our own backyards. Not even wild creatures do that.

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  9. Justin Woods

    Ethicist and Public Intellectual

    "In Australia dingoes greatly reduce kangaroo and red fox numbers, which in turn reduces grazing of vegetation and predation of native animals, helping to conserve and protect biodiversity."

    By the same token, a well aimed .22 or .303 can reduce kangaroo and fox numbers, as well as dingoes who eat little babies, or maim little kiddies on Fraser Island.

    Why do you maintain that sharks have an inviable right to eat smaller fish or humans. You take no account of the damage sharks do to the lesser fish species on whom indigenous people throughout the world rely for sustenance.

    It is as if some people believe that only they have the right to determine what fish species inhabit the ocean, giving no thought to other animals.

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    1. Nick Kermode

      logged in via email @hotmail.com

      In reply to Justin Woods

      "You take no account of the damage sharks do to the lesser fish species on whom indigenous people throughout the world rely for sustenance."

      Absolute rubbish Justin. Sorry you have no idea what you are talking about. Places in the world with the most sharks have the most healthy populations of fish and sharks have been proven to control the health of coral reefs http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0074648
      Coral reefs are central to indigenous peoples fish protein, and a good source of income from tourists who come to dive and snorkel. Overfishing on the other hand.....

      "It is as if some people believe that only they have the right to determine what fish species inhabit the ocean, giving no thought to other animals."

      To finish your post and sum up your position with that statement has to be a Freudian slip surely. No one could be that contradictory in a few sentences.

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    2. Peter Hindrup

      consultant

      In reply to Justin Woods

      Justin: A bit out of date, I think.

      'By the same token, a well aimed .22 or .303 can reduce . . .'

      A 303 today? A 306 (30 O 6) or preferably a 270 is a far better choice.

      A .22? I used to hunt with one, long ago. A self loading, or as often referred to as a 'semi'.

      To hunt kangaroos, foxes or dingoes with anything less, without a second shot under your finger is to risk leaving wounded animals to die in agony.

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    3. James Hammond

      Ecologist

      In reply to Justin Woods

      "By the same token, a well aimed .22 or .303 can reduce kangaroo and fox numbers, as well as dingoes who eat little babies, or maim little kiddies on Fraser Island."

      No doubt humans are the apex predator of most ecosystems, but you seem to forget the effort (and in human terms, this means money) required to fulfill this role. Maintaining appropriate trophic balance means that we get to have ecosystem stability FOR FREE. Great Whites dont charge money to keep seals and other species (that eat our valuable crustacean and mollusc food sources) in check.

      Alternatively, the financial impost that would occur if humans needed to fully accept the apex role would be enourmous. This is what 'ecosystem services' are all about. Its time that people understand the impossibility of humans doing this, particularly in Australia, with its huge landmass and huge coastline.

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    4. Justin Woods

      Ethicist and Public Intellectual

      In reply to James Hammond

      Great Whites mighten charge money for eating surfers, but you fail to take into account the lost productivity of that human they devoured. They would have paid taxes to support university research programmes like proving there is no sea ice in Antarctica.

      As to the seals, let's invite the Nippon Maru to fix that problem should there be too many of them.

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    5. Nick Kermode

      logged in via email @hotmail.com

      In reply to James Hammond

      Hi James, great point. In addition to the "financial impost" and impossible logistics would be the fact that we (humans) don't really know how to maintain a trophic balance. Sure some of the relationships are obvious but there are many we understand little about and definitely some which we have no idea about at all. The "rewilding" of Yellowstone Park had many expected benefits, some that we had not thought about at all and probably some we don't even realise. I expect there are even more unknowns in the trophic cascade below Great White sharks. Bottom line is though, we know enough that we should leave it to the experts and definitely know enough to make sure there are enough of them to leave it to.

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    6. James Hammond

      Ecologist

      In reply to Justin Woods

      And when the products of the hunt cannot be sold, the government will need to subsidise the industry, at taxpayers expense.

      Dont forget the problematic ethical and welfare issues that would arise with killing seals and other charismatic species in Australia (we see this all the time with kangaroos and other over-abundant species). Apex predators provide this service out of sight and out of mind.

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  10. Peter Gerard

    Retired medical practitioner

    The history of mankind demonstrates our alacrity to kill or torture our own kind often with great inventiveness and on a massive scale. Collectively though, when our livelihoods or lives are threatened, by another species, we take umbrage and demand immediate redress. It doesn't seem to matter that the human lives lost as a result of wild animal attack are minuscule compared to those lost by homicidal activity and also pale into insignificance compared to the wild animals killed by humans for food or in the name of sport. We are capable, as a species, of great compassion and respect not only for our own kind but for non human animals as well. Unfortunately these virtues are too frequently negated by our egoism, greed and lack of empathy. The latter, combined with burgeoning human populations, habitat destruction, a macabre desire for various animal parts, our own foolishness and risk taking, imply a grim future depleted of many wonderful wild creatures.

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