The most effective way to minimise the impacts of invasive weeds is to prevent them establishing in the first place. New species can colonise an area rapidly and successful control depends on a rapid, effective response.
Eradication strategies aim to completely remove the weed from New South Wales. Eradication depends on many factors, including the potential environmental impact of eradication, the size and number of populations of the weed, its biology, native range, preferred habitat, suitable climate and how well this matches conditions in the new environment.
If early detection and rapid, effective response cannot successfully control the spread of newly introduced species, they can become widespread. In these instances, eradication will no longer be practical and priorities for containment or control must be determined instead. Where possible, ‘biosecurity zones’ or containment lines are employed, providing a long-term management strategy for emerging weeds to prevent further spread.
Priority new and emerging weeds impacting biodiversity in New South Wales include:
Assessing weed risk and prioritising action
The Department of Climate Change, Energy, the Environment and Water uses the NSW Weed Risk Management System to assess individual weed species at the statewide level for conservation areas, including aquatic areas. This assists with priority setting, ensuring that the highest-risk weeds and those that are most easily controlled are tackled first.
The department has completed conservation-based weed risk management assessments for over 150 species, with each species assigned one of 6 management categories:
- Eradication: remove the weed species from NSW
- Destroy infestations: significantly reduce the extent of the weed species in NSW
- Contain spread: prevent the ongoing spread of the weed species in NSW
- Protect priority sites: prevent the spread of the weed species to key sites/assets of high economic, environmental and/or social value
- Manage weed: reduce the overall economic, environmental and/or social impacts of the weed species through targeted management
- Manage sites: maintain the overall economic, environmental and/or social value of key sites/assets through improved general weed management.