The Department of Conservation’s island pest eradication teams are among the best in the world. Ninety islands have so far been declared pest-free, including near-shore islands such as Kapiti and Resolution, and distant islands such as Raoul and Campbell, which at 11,700ha is the largest to be declared pest-free. Next on the list, thanks to Gareth Morgan, is the Antipodes Islands. Morgan’s campaign to raise money to rid these islands of introduced mice is almost halfway to its $1 million target. Morgan started the campaign after his Our Far South expedition, which took a boatload of scientists, communicators and paying travellers from Invercargill to Antarctica, via several sub-Antarctic Island groups, in February.
The Antipodes Islands, which lie 800km southeast of Bluff, are a group of uninhabited islands, dominated by the 2000ha Antipodes Island, home to such species as parakeets, erect-crested penguins and the antipodes snipe and a breeding ground for the antipodean wandering albatross. The island is in good condition but mice – the only introduced mammal – compete with birds for seeds and insects and eat the eggs and chicks of small seabirds such as petrels. Money is coming in from school sausage sizzles, a resthome’s sales of knitted penguins and a recent charity auction that raised $33,000, with punters bidding on such treats as a trip to Snares Island with DoC and a cast of Happy Feet’s foot. Once the money is raised, DoC will do the pest eradication, a simple but effective process involving a helicopter bait drop followed by ground baiting. Morgan hopes the $1 million will be raised by Christmas, meaning the pest eradication can take place next year. And after that? “As soon as we’ve knocked off Million Dollar Mouse, I’ve got plans for tackling one of the big islands closer to the mainland.”
Lin Rose asks: I lived in the United Arab Emirates for three years and would like to know why cacti don’t grow naturally in the deserts there.
“The science of why things live where they do is biogeography, and there are two strands to it,” says Phil Garnock-Jones, emeritus professor of botany at Victoria University. “Ecological biogeography explains distributions in terms of habitats, whereas historical biogeography explains them in terms of the constraints of past distributions, combined with ability to disperse. “The question is posed in terms of ecological biogeography: the UAE is a desert land and cacti are well-adapted for life in the desert. The answer, however, comes from historical biogeography. True cacti are almost entirely American; apart from a single species in Africa, they aren’t found anywhere in the old world. In old-world deserts, unrelated cactus-like plants have evolved with similar structural and physiological adaptations to desert life, such as euphorbias in the African deserts and iceplants in southern Africa. “But why don’t these unrelated cactus-like plants thrive in the UAE? The answer comes from ecological biogeography. The UAE has about 800 species of native plants, which grow in two environmental zones. The plants of the marshes and wetlands need to cope with high salinity; rushes and salt-tolerant small herbs and succulents are the main growth forms. “The deserts are mostly shifting dunes, with very hot temperatures, very dry air and high soil salinity. Here, twiggy or thorny shrubs, creeping perennials and annual grasses and herbs do best. It’s not a suitably stable environment for large fl eshy, cactuslike growth forms.”
Correction: Thanks to those astute readers who pointed out a mistake in a recent column. The USS Halibut, the nuclear submarine that visited New Zealand in 1960, was not the world’s first nuclear submarine. That, of course, was the USS Nautilus, which was commissioned in 1954. My apologies for the error.
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