Invading aliens with 'familiar faces'

A database of the world's most invasive pest species may surprise some New Zealanders with the number of "familiar faces" already within their borders, says an expert.

Maj de Poorter, New Zealand co-ordinator of the Auckland-based invasive species specialist group of the World Conservation Union (ICUN), said the surprise might be doubled when they saw how many NZ natives were regarded as invasive pests overseas.

New Zealand's pohutukawa is an invasive pest tree in South Africa, flatworms are a noxious killer that wipes out the humble earthworm in Britain and native mudsnails are regarded as a tiny pest with a voracious appetite in American trout rivers, she said.

And last week US scientists were speculating that a New Zealand mollusc that invaded San Francisco Bay in 1993 was consuming the clams controlling the phytoplankton in the bay, creating a "bloom" that may cause environmental problems when dying plants decompose and rob the water of oxygen.

Dr de Poorter, an invasive species researcher at Auckland University, said the Global Invasive Species Database (GISD), launched last Friday, would make more information available to people working on biosecurity and make it easy for people around the world to check out pests.

The database canvasses invasive species around the world, including micro-organisms, plants and animals, their ecology, human and environmental impacts. It also maps their invasive pathways and how to develop tools to deal with them, including early warning systems, economic and risk analysis, legal issues, control and management, and education.

Dr de Poorter said "biological invasions" by alien species were now reaching as far as Antarctica. The website included a list of 100 of the world's worst invasive alien species.

She said invasive species specialists in NZ had been involved in running workshops for people in the Pacific Islands. This was important because the islands provided a buffer zone where some pests might be detected before they reached New Zealand.

Some of the most underrated pests were invasive ants, such as fire ants and yellow crazy ants, because if they established in this country not only native wildlife and livestock would be affected, but so would people.

"Where some ant species have run amok overseas, people are not able to stand still without being attacked," Dr de Poorter said.

The database would save researchers and biosecurity workers a lot of time, and make accurate information on pest species easily available to members of the public.

"It can be a scary aspect of invasive aliens such as sea squirts or rocksnot that they gain a foothold before anyone realises they are present."

- NZPA