ARTICLE : WEED CONTROL

 September 2002 – Biological control options for invasive weeds of New Zealand protected areas.

Reprinted here is the abstract of a report by Vicky Froude, published by the Department of Conservation in Science for Conservation 199.   The 68-page report can be purchased for $30 plus $2 post and packaging from Science Publishing, Department of Conservation, PO Box 10-420, Wellington.

Abstract

More than 240 invasive weed species adversely affect indigenous biota and ecosystems of lands and waterbodies managed by the New Zealand Department of Conservation.   Potentially high establishment costs limit biological control programmes to a few species of concern, although there may be opportunities for joint programmes with other agencies.

Biological control may be most useful ecologically where relatively few invasive species proliferate and their removal would bring significant conservation gains (e.g. Salix cinerea, S. fragilis, Pinus contorta).   It may, however, be difficult to pursue biological control programmes for species that are valued in other contexts such as soil conservation.

Programme outcomes cannot be reliably predicted and it may take many years before these are known.   Biological control works best as part of a comprehensive weed management programme.   If successful it may eventually reduce or remove the need for conventional control.

This review of the potential contribution of biological control to the Department's weed management strategy addresses:
weed impacts;
benefits, risks and measuring biological control outcomes;
international programmes and their outcomes for biological control of weeds in natural areas;
New Zealand investigations for each invasive weed species affecting New Zealand protected areas;
and an assessment process for prioritising biological control investigations.

Victoria Froude
Pacific Eco-Logic Ltd   vfroude@paradise.net.nz