What is cute, furry and ecologically devastating?

Answer: a possum.

Even this little fellow, still not fully grown, would wreak havoc on vegetables and fruit trees, and in an indigenous forest environment, shrubs, trees, bird young and eggs.

Recently, we stayed at our friends’ lifestyle block near Tokomaru, nestled in the foothills of the Tararua Ranges [click here to view map]. As well as growing their own fruit and vegetables (and animals), they have replanted the gully that runs through their land with locally sourced native plants. So, they do not look kindly upon the nocturnal mastications of possums. The less “street-wise” of the furry marsupials are lured in to traps (unharmed) with fruit and then later dispatched (very quickly) with a .22 rifle.

Possums are now estimated to number 70 million in New Zealand, and have become a pest that inflicts enormous damage on New Zealand’s indigenous vegetation and birds. However, only 100 years ago, they were highly valued and strictly protected.

As explored in a previous post, the “furry money-spinner” – the history of the possum in New Zealand, possums were first introduced to New Zealand in the 1830s. It was thought that their fur would form the basis of a lucrative industry, and until the late 1930s, they were protected.

The damaging effects of possums on indigenous flora were suspected even in the early 20th century, but it was not until the ground-breaking research of two scientists was published in 1949 that these effects were established beyond doubt. There is now little debate about the devastating effects of these voracious eaters – they consume an estimated 21,000 tonnes of vegetation a night. They can cause the complete collapse of a forest canopy – especially of “possum favourites”, such as rata and kamahi. Possums are omnivorous and also eat the eggs and chicks of native birds (and, sometimes, adult birds).

Today, an immense amount of effort and money goes into attempting to control possums using traps or poison. Some methods of possum control are highly contentious and polarise society [see, for example: Protest on the landscape – Wallaceville, Upper Hutt]. Whatever the method of control, the battle against these ecological interlopers is unlikely to cease any time in the near future.

See also: The ebb and flow of a rural township: Tokomaru; Why were stoats and ferrets introduced into New Zealand?

Photo top: In spite of my knowledge of the damage that possums do, it was difficult not to feel sorry for this button-eyed, furry little character, whose only crime was to be introduced by ecologically-ignorant humans into an environment completely unsuited to them (Photo: C. Knight). Above: Possums have damaged the upper canopy of these forest trees on the slopes of Mt Karioi, south of Raglan, seen in 1993. Photo: Department of Conservation, reference: 10049782

One thought on “What is cute, furry and ecologically devastating?

  1. Alan December 30, 2011 / 10:28 pm

    Does make me wonder (again and again) about the “wisdom” of the recent introduction of foreign dung beetles to NZ (I think I read somewhere that we already have 7 or 8 native species).

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