12 January 2009

An "ecosystem meltdown" by well-meaning humans


Macquarie Island, halfway between Australia and Antarctica, was discovered in 1810, and not surprisingly, all of the island's fur seals, elephant seals and penguins were killed for fur and blubber.

Rats and mice invaded the island from the docked and beached ships. Cats were then introduced to keep the rodents under control. Rabbits were then added to give shipwrecked sailors something to eat.

Step 1: The cats fed on the hapless rabbits and multiplied rapidly. The island then lost two endemic flightless birds, a rail and a parakeet. But the rabbits were such successful breeders that they began to damage the vegetation, so…

Step 2: In the 1970s, the myxomatosis virus was introduced; it almost literally decimated the rabbit population (from 130,000 to under 20,000) within a decade. That helped the vegetation, but…

Step 3: Without enough rabbits to eat, the cat population turned instead to local burrowing birds, so to protect the birds…

Step 4: In 1985 conservationsts began killing the cats. The last cat was killed in 2000. For some reason they failed to anticipate the predictable consequence…

Step 5: The rabbit population rebounded strongly, to such an extent that they began to strip the island bare of vegetation. The lack of vegetation caused a massive landslip that wiped out much of an important penguin colony. ( before and after photos above). In order to restore the vegetation...

Step 6: The Tasmanian Parks and Wildlife Service now plans to eradicate all 130,000 rabbits, all 36,000 rats and all 103,000 mice.

What could possibly go wrong?

2 comments:

  1. The late Michael Crichton in an appendix to his novel, State of Fear, talks about the bad science related to the global warming hype. One of his reasons for restraining our efforts for managing ecosystems is that we don't know what we are doing and we are not very good at it. Your example of the failure to help manage the small island you describe is unfortunately not an isolated example. I am not aware of many successful attempts.
    Its not nice to fool around with Mother Nature, to coin a phrase.

    ReplyDelete
  2. every solution eventually becomes a problem...

    ReplyDelete

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