From the very top of the North Island to the bottom of the South Island, New Zealand is on the verge of disaster – and a small arboreal marsupial from Australia is to blame – the possum.

Introduced in the 1830’s to provide the basis for a fur industry, the possum found the New Zealand forests a paradise. More used to coarse Australian gum leaves, the foliage in New Zealand offered an endless variety of tasty and nutritious food. Working their way down a list of preferred groups the possums have gradually removed species after species from the forest. Native birds have been out competed for food, whole forest canopies are disappearing – a total irreversible change is happening.

If that wasn’t enough, the possum is the main reservoir for bovine TB. Cattle and deer all over the country are being infected at an increasing rate. Apart from the major inconvenience for farmers the threat of a ban on overseas meat exports hangs over the industry. Research being carried out at the moment has only shown up how little is known about the disease in possums and difficulties faced in controlling it.

Current control methods can only offer short term relief. Aerial dropping of 1080 poison in very inaccessible areas and the use of the growing pool of unemployed trappers – redundant from the collapse of the fur industry – are very expensive, too much to consider for the whole country, crippling even for those areas of high conservation and agricultural value.

There seems to be no solution – New Zealand cannot look for help overseas because nowhere else has the nightmare of the possum.