Perennial grass weeds in Australia: impacts, conflicts of interest and management issues
A.C. Grice, CSIRO Sustainable Ecosystems, Private Bag PO, Aitkenvale, Queensland 4814, Australia and CRC for Australian Weed Management.
Introduction
Australia has around 27 000 introduced plant species, about 2700 of which have naturalized (Hosking et al. in press), that is, they have established self-replacing populations (Richardson et al. 2000). About 30% of the plants naturalized in Australia (798 species) have been classified as being major weeds of natural or agricultural ecosystems somewhere on the continent (Groves et al. 2003).
Grasses (Poaceae) are prominent amongst Australia's naturalized plants. There are 375 grass species in Hosking's database, representing about 14% of the naturalized flora. Of these 375 species, 141 (37.6%) have been classified as major weeds (Groves et al. 2003) suggesting that grasses have shown a somewhat greater tendency than naturalized plants as a whole to become major weeds. Seventeen grass species have been declared 'noxious' in one or more states or territories of Australia. Three grass species are amongst the twenty Weeds of National Significance declared under Australia's National Weed Strategy. They are serrated tussock (Nassella trichotoma (Nees) Hack. ex Arechav.), Chilean needlegrass (Nassella neesiana (Trin. & Rupr.) Barkworth) and olive hymenachne (Hymenachne amplexicaulis (Rudge) Nees).
Plant Protection Quarterly (2004) 19 (2) 42-47.