Emerging Issues
The Royal Society speaks out on pests

by John Ogden


A recent issue (March 2014) of the Royal Society of New Zealand’s “Emerging Issues” papers, addresses the challenge of pest management. This is a ‘heavy’ document, put together and reviewed by panels of experts and with over 100 references. It contains information about invertebrate pests, pathogenic micro-organisms, weeds, vertebrate pests, freshwater aquatic pests, and marine pests. This wide coverage somewhat dilutes the overall impact of the paper, presumably because it is hard to come up with specific recommendations applying in all these varied cases, except that more research and more action is needed in all cases!

There are some quite staggering estimates of the economic impacts – for example eradication costs for the Painted Apple Moth (1999-2006) were $58 million, but the savings (i.e. averted costs) amount to possibly as much as $259 million over 20 years. The cost of managing vertebrate pests – possums, deer, rabbits, rats, mustelids etc. is estimated at a billion dollars every year, but it could be higher than this – possibly 3.3% or nearly 2% of GDP. New Zealand’s outstanding international reputation in eradication of pest mammals for biodiversity protection on islands is summarised. The future challenge of eradication of mammalian pests on inhabited Islands, and the huge vision of a “predator-free New Zealand” are briefly mentioned and referenced (http://predatorfreenz.org/).

“There are only two native land mammals in New Zealand (two bat species), the result of 80 million years of geographical isolation. In contrast, 32 species of mammals (and 35 birds) have become established. New Zealand’s native flora and fauna are particularly vulnerable to predation by mammal pests. Rats, mice, weasels and stoats, hares and rabbits, hedgehogs, possums, wild pigs and feral cats all present serious threats. Strenuous efforts are being made to create vertebrate pest-free areas on islands and in predator-fenced sanctuaries. However, these areas are mostly small, and reinvasion is always a risk. Emerging issues include the need for:

• the cost-effective, humane management of vertebrate pests at very large scales;

• larger areas free of mammal pests, and keeping them free by effective monitoring, detection and rapid removal of

• maintenance and more public support for mammal pest control or eradication, especially where this involves toxins (e.g. the Predator Free New Zealand initiative).

Those three bullet points all apply to Great Barrier Island – if we are to eradicate the island’s pests we will need;


(1) community support and involvement especially in inhabited areas;

(2) an acceptable method applicable to large areas of diverse topography, and

(3) effective monitoring and biosecurity. The Island could benefit from being a large scale test case, but the economic benefits must be apparent to all before this will be achieved.

To read the whole item, and others involving ‘green economy’ and climate change, google ‘New Zealand Royal Society Emerging Issues’, or see: www.royalsociety.org.nz/pestmanagement


Environmental News Issue 33 2016