ON GREEN MOUNTAIN - The New Wild: Why Invasive Species will be Natures Salvation - page 7

Cape Town ornithologists first detailed the carnage during a visit in 2001. They calculate that only a
quarter of the 1.6 million petrel chicks that hatch each year on Gough make it to adulthood. Virtually all
the rest are eaten by mice as they sit immobile in their underground nests. Even albatross chicks, which
may be the size of geese, succumb to the nighttime attacks by these marauding monsters, says an in-
credulous Ross Wanless, who has taken video of the gruesome scenes. 10 “It's like a tabby cat attacking
a hippopotamus,” says Geoff Hilton of the RSPB, which wants to exterminate the mice.
How do you get rid of two million mice on a remote island? A feasibility study recommended hiring
a helicopter to bomb the place with some hundred tons of brodifacoum, an anticoagulant poison widely
used against rats, at a likely cost of about $2.5 million. Even then, since many of the mice live in caves
and volcanic lava tubes, complete eradication could not be guaranteed. And there is a risk that the pois-
on could instead end up killing off the Gough moorhen. Perhaps not surprisingly, the enterprise was on
hold in early 2014. 11 The super-mice remained in charge, and they may remain so until they run out of
food.
Despite their atypical nature, simple island ecosystems, such as on Gough, have become the test
cases for what we think about aliens, perhaps because, surrounded by ocean, they provide simple and
understandable terrain for these battles. The most discussed of all sites of invasions is Hawaii, where
both those vehemently opposed to alien species and those who see their virtues are willing to make their
cases. On one side is Daniel Simberloff of the University of Tennessee. A guru among invasion biolo-
gists, he is now in his seventies. He studied half a century ago under Harvard's legendary forest ecolo-
gist and pioneer of island biogeography, Edward O. Wilson. He says Hawaii is the site of an “invasional
meltdown.” 12 On the other side is Joseph Mascaro, a post-doc at Stanford University, forty years young-
er than Simberloff, whose work in Hawaii was publicized in the groundbreaking topic Rambunctious
Garden , by journalist Emma Marris. Mascaro says Hawaii is simply exhibiting some textbook examples
of what he and other ecologists are now calling “novel ecosystems.” 13
The Hawaiian Islands are the most northerly of the Polynesian islands in the central Pacific. They
are an archipelago of volcanic islands, and one volcano, Mauna Loa, still spews lava today. Others are
long extinct and have been above the waves for ten million years or more. Species reached the islands
on the winds and waves, in the gullets of migrating birds, and clinging to the trunks of floating trees.
They all made themselves at home as best they could. Lichens turned the lava to soil, birds spread seeds,
and seeds took root. Evolution hit overdrive. Genetic mutations created new forms through the constant
rolling of DNA dice, and the successful species flourished. More than a hundred bird species evolved
from maybe twenty arrivals. Finches, probably from Asia, evolved into fifty-six species of endemic
Hawaiian honeycreepers, almost half of which are still flying around, pollinating both native and alien
vegetation.
Many other unexpected things happened. As environmentalist Louise Young noted in her topic on
islands: “Wingless and blind insects evolved . . . land snails became tree snails . . . unusual varieties of
blooming trees [emerged,] like lobelias, hibiscus and tree violets.” 14 But this largely random collection
of species also contained some big gaps. “Hawaii lacked reptiles, amphibians, flightless mammals and
ants,” says Mascaro. 15 Pollinating insects never got going there, leaving the role to the remarkable col-
lection of birds.
Human interference on Hawaii probably began when Polynesian canoes rode ocean currents from
the Society Islands onto the beaches of Hawaii some fifteen hundred years ago. The newcomers cut
down lowland forests for farmland, while leaving intact the upland forests, which they regarded as sac-
red. They exterminated some meaty flightless birds. But they brought the first freshwater fish, rats and
pigs, and the candlenut tree that they used to make canoes and that provided nut oil for lamps. The new-