Hi all,
The eradication of rats on Campbell Island is fantastic news not least
because rats are a significant predator of eggs, chicks and even adults of
the smaller nesting seabirds. The results may also have very positive
spin-offs for other islands as Pete Milburn has suggested.
Specifically I'm thinking about Australia's Macquarie Island. Recently
Macquarie Island was declared cat free after a concerted effort to eradicate
cats ended in success. However, still remaining are rabbits, black rats and
house mice. Rabbits are implicated in significant changes to the vegetation
(destruction of entire fields of MI Cabbage and Tussock Grassland; the later
a favoured breeding site for a number of petrels). Rabbits also provide an
abundant source of food for Southern Skuas during lean times. This may in
turn artificially elevate the numbers of this natural predator leading to
increased predation rates on smaller seabirds at other times. The impacts
of mice are not that well known but using the precautionary principal I'd
suggest they do more harm than good (i.e. consuming seed that might
otherwise germinate).
Anyway enough background on why these mammals are bad. At 11,300 ha Campbell
Island is a pretty big island and one of the largest from which a small
exotic mammal has been eradicated. Fortuitously, Macquarie is quite similar
in climate, land form and size (12,785 ha) and as such a blueprint now
exists for rat eradication.Given the large cost involved in such operations
the successful outcome at Campbell sets a very special precedent that could
be used to support moves (help raise the necessary funds/application of any
lessons learnt etc) to continue pest mammal eradication on Macquarie Island.
I look forward to the day when Macquarie becomes a more suitable breeding
site for prions, blue and soft-plumaged petrels, diving petrels and
storm-petrels.
Regards
Rohan
Rohan Clarke
Department of Zoology
La Trobe University
Vic 3086
office 03 9479 1672 mobile 0408 947 001
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