Weeds can be classified into three distinct classes based on
the level of threat they pose to an ecosystem.
1. Ecosystem transformers that can dominate and destroy
native vegetation communities within 10 years
2. Invasive weeds that are highly mobile within a native
vegetation community but do not have the immediate
potential to alter it in the short to medium term
3. Naturalisers that reside mainly on the edge of the native
vegetation communities and have little potential to be
either ecosystem transformers or highly invasive.
The class, density and distribution of weeds will determine
the effect on the environment. This may include:
• competing with the local native plants for space, sunlight,
moisture and nutrients
• inhibiting the germination of native plants
• altering the habitat of local terrestrial and aquatic flora
• changing the fire regime
• modifying the soil characteristics
• favouring the establishment of other weed species.