Many perennial grass species have been introduced to Australia since 1788. Some species have adverse impacts on biodiversity and agriculture and are recognised as weeds.
Some introduced grasses, such as serrated tussock and Chilean needlegrass, are recognised as Weeds of National Significance. Many others have been listed in regional weed strategies as threats to biodiversity.
Why are introduced perennial grasses a threat?
Features of introduced perennial grasses include:
- vigorous growth
- prolific seed production
- effective seed dispersal.
These characteristics enable many exotic grasses to compete strongly with, or even displace, native vegetation. Exotic perennial grasses may also change the fuel load in plant communities. The changed structure and fire regime of the habitat is likely to have a negative impact on both native animals and insects.
In September 2003 the NSW Scientific Committee made a final determination to list the 'invasion of native plant communities by exotic perennial grasses' as a key threatening process (KTP) in NSW.