Attempt to Control Invasive Species Backfires Spectacularly on an Antarctic Island

By Eliza Strickland | January 12, 2009 4:22 pm

Macquarie IslandThe cats ate the birds until the humans killed the cats, but now the rabbits are out of control.

That’s the sad state of affairs on Macquarie Island, an island near Antarctica that was declared a world heritage site in 1997 due to its status as the sole breeding ground for the royal penguin. For decades researchers have attempted to get rid of the invasive species that have altered the island’s ecological balance, but a new study notes that the latest effort, an all-out push to eradicate feral cats, has had the unintended consequence of allowing a boom in the rabbit population. Those rabbits have quickly denuded the landscape of its vegetation, researchers say.

Things began to go wrong on Macquarie Island … soon after it was discovered in 1810. The island’s fur seals, elephant seals and penguins were killed for fur and blubber, but it was the rats and mice that jumped from the sealing ships that started the problem. Cats were quickly introduced to keep the rodents from precious food stores. Rabbits followed some 60 years later, as part of a tradition to leave the animals on islands to give shipwrecked sailors something to eat [The Guardian]. The invasive species all thrived to the detriment of local species, and by the 1970s biologists were concerned enough to introduce a rabbit-killing disease called myxomatosis, which thinned the rabbit herds considerably. However, that left the cats with less available prey and caused them to begin hunting the island’s native burrowing birds.

By 1985 conservationists decided that all of the cats would have to be shot, and the job was done by 2000. But that move allowed the rabbit populations to flourish once more. Since the eradication of cats eight years ago there are now an estimated 100,000 rabbits munching the foliage of Macquarie Island…. Removal of plant cover is thought to make penguins more vulnerable to predation [BBC News]. Now scientists say they must wipe out the rabbits completely, and say that it will cost about $17 million to eradicate the invaders and restore native plant life. They expect to begin dropping poisoned bait around the island next year.

In the study that sums up this history, which will be published in the Journal of Applied Ecology, study coauthor Dana Bergstrom says that Macquarie Island should serve as an example of what not to do. “Our study shows that between 2000 and 2007 there has been widespread ecosystem devastation and decades of conservation effort compromised. The lessons for conservation agencies globally is that interventions should be comprehensive, and include risk assessments to explicitly consider and plan for indirect effects, or face substantial subsequent costs” [Telegraph].

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Image: Australian Antarctic Division, showing shots from before and after the plague of rabbits

CATEGORIZED UNDER: Environment, Living World
  • Uncle Al

    The Enviro-whiner trinity: expensive, shoddy, deadly. Call Carolina Biological Supply and tell them every rabbit they catch is theirs to keep for free. Second best is to loose some ecology graduate students short thesis topics, “Poisson statistics of feral rabbit slaughter”, plus a wood chipper. If you are really desperate… Put Washington in charge of maximizing rabbit reproduction. They can outsource to Canukistan Maritime Province cod restoration.

    $17 million/100K rabbits = $170/rabbit

    Is that more than PET bottle refunds? The US homeless problem is solved.

  • sinthetic

    Uncle Al for president!

  • Mr. H

    It seems that instances of “successful” biological control are few and far between. The ammount of research and testing that needs to be done BEFORE a biocontrol plan is put into action probably outweighs the benefits in most circumstances.

  • Jayson o.

    i think this is bull crap that we are killing rabits at $170 a hit i think this is why america is in billions of dollars of dept.

  • joey r.

    I think spending $17 million dollars on killing rabbits is entirely superfluous. All you need is maybe 10 people all with guns and plenty of bullets and let them loose on the island. PROBLEM SOLVED!

  • robert s


  • anna.b

    why in the world would you spend $17 mill juszt to kill a rabbit! man thtsz non-sense! thtsz killin Godsz animalsz! what them rabbitsz do to you?? but $17 mill?? yeaa rite!

  • Laura M.

    I think it’s crazy that they are killing rabbits to save billions. They should spend money on making sure the rabbits are staying alive on the island

  • Travis

    I think that they should just find a place for them to have a safe home to stay at

  • chris g.

    ship the rabbits to Ethiopia

  • chris g.

    and ship the cats to china

  • Chandler brown

    the rabbits should move to another country and the cat need to go to china they eat cats there

  • Kari M.

    dont spend all that money to kill those poor animals!!!!!!!!!!!!!!!!!!

  • Maria P

    I think they need to just seperate them and let them have a safe place to stay at!!

  • byron t

    i think it wrong to spend all that money on that.

  • Jasmine R

    Why did the cats eat the birds? They should just leave the rabbits alone and move the other animals to a differernt country. they are just wasting alot of time and money killing those rabbits.

  • B Saito

    Sure we should just move all those animals instead of killing the invasive species! I’m sure it’s much more practical and cost efficient to just round up every single on of those animals, find another place for them to live where they won’t mess up the ecosystem, and ship them all there rather than simply kill them!
    In all seriousness though, I don’t understand why they tried using disease and are now going to use poison to exterminate the rabbits when they simply shot the cats. Shouldn’t shooting the rabbits work just as well?

  • chris

    Why do they think that further manipulating the environment will be successful?

    Take the 17 million, creat a safe habitat for the birds somewhere and stop opening pandora’s box so to speak.

    Killing off the cats and rabbits is as unnatural as transplanting them there in the first place.

    Also humnas don’t get the luxury of a more developed species spending resources to ensure our survival, at least I don’t think we do :).

  • Michael

    They did the same thing in ST. Croix USVI a long time ago. The ships brought rats, so they brought snakes to get the rats, then they brought mongooses to get the snakes. The mongooses are still there, and there are relatively few birds on the island compared to mongoose free places since mongooses eat bird eggs as well as snakes (and rats for that matter).

  • Jill

    Anyone who thinks the rabbits can be eradicated by a few people with guns is seriously deluded.

    Anyone who thinks the rabbits should be allowed to live because they’re cute furry animals is a total idiot. Charismatic macrofauna sure… but in that circumstance they are vermin and destroying the ecosystem.



  • paulineinuk

    and who else will pick up the poisiond bait /or eat the piosiond flesh/ birds for one, opps, where have all the birds gone,history repeates itself,wipe out one species ,and inbalance is the result,the ball then rolls on and on. yet so called inteligent man still cant see it

  • Markquis

    A rabbit farm is what they created, use this as an advantageous muck up and ship the rabbits to African or Southeast Asia where it can do some good.

  • Punkrawk Bbob

    Why not just recreate dinosaurs with DNA from mosquitoes preserved in tree sap? Then set those loose on the island. That’ll thin out the rabbit population no problem. Probably any human infestation while you’re at it.
    Why not? Works in the movies. Not like we could really ruin much more at this point.

  • Mina C.

    *sigh* Why does it seem that mankind is always the source of the problem to begin with?

  • Michael Gibbs

    That 17m to eradicate the rabbits will come from the pockets of Australians, as the island is a province of Tasmania. Personally I think it’s a small price to pay for man’s mistakes. We stuffed it up, we have to fix it before the island completely erodes due to grass munching by rabbits. The British used to enjoy releasing rabbits in the 1800’s due to it giving a sense of home to their sailors, something to hunt. Sounds nice in theory, but unfortunately not much was known about ecology back then so the distasters unfolded without their knowledge. We must fix and preserve as much of this planet before we trash it. This is a good island, and has potential, sure the average temp is only 4-7 degrees centigrade, however as mentioned in the article, it’s a mass penguin breeding ground, and has some interesting volcanic activity, not to mention it’s one of the only islands at all this far south.

  • Ian

    The absolute catastrophe is the poison bait that was used was Brodifacoum which resulted in the deaths of 883 Giant Petrels, Skuas, Black ducks and many other resident bird species.
    The baiting campaign was called off after birds starting dieing everywhere on the Island. Only 8 per cent of the bait was deployed…can you imagine what damage would have been done if the”authorities” had aerial baited the full 300 tonnes of Brodifacoum?


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