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What are invasive species?

Invasive species are animals, plants, parasites or disease-causing organisms that occur outside their natural range due to human activities.

The species threaten valued environmental, agricultural, cultural or other social resources by the damage it causes. This can include organisms endemic to a country other than Australia or a native species moved to a new location.

The problem for waterways

Invasive species in waterways and along riparian land are an increasing threat to the health of Victoria's rivers, estuaries and wetlands.

The establishment and spread of invasive species are often a symptom of broader land use change and disturbance. Compared to most land, waterways (including riparian land) appear especially vulnerable to invasive species.

Riparian land is prone to invasion

Riparian land is prone to invasion due to high productivity and frequent disturbances.

The spread of invasive species through waterways and riparian land is assisted by high connectivity due to water flowing downstream or laterally to the floodplain and associated wetlands. It is common for significant movement of invasive species to occur during flood events.

Invasive species affect waterway conditions and can potentially threaten environmental, social, cultural and economic values.

Environmental impacts may include predation on, or competition with, native species, habitat loss and water quality or sediment changes, nutrient levels and disease transmission.

The impacts associated with invasive species are often underestimated as there may be a time lag between their introduction and their effects being noticed, or it may be difficult to calculate the costs associated with the damage caused.

Some invasive species can pose a risk to environmental values but also support social and economic values, such as recreational fishing. Therefore, a balanced management approach is required to reduce the impacts of invasive species that cause substantial harm while acknowledging that, in some limited cases, invasive species may provide other benefits that are valued by the community.

Managing invasive species in Victorian waterways

Invasive species management is complex and requires high cooperation between international, national, state and regional agencies.

The Victorian Government's Environmental Partnerships and the Invasive Plants and Animals Policy Framework provide the overarching strategic approach for managing invasive species across Victoria.

The Victorian Waterway Management Strategy sets out the policy direction for waterway health issues, including the threat from invasive species.

Taking a holistic and integrated approach

Managing invasive species in waterways needs to be holistic and integrated with other waterway management activities, other pest plant and animal control work, and fisheries management activities.

It is challenging to eradicate invasive species, so management activities to prevent their establishment are critical. To date, management has focused mainly on established invasive species rather than minimising the risk of new species invasions or rapid response to new incursions and containment.

It is often impossible to eradicate invasive species in waterways

Therefore, management activities to prevent their introduction and establishment are critical. Prevention provides a higher return for investment than eradication, containment or managing their impacts across widespread areas.

Coordinated action across Victorian government agencies and working with the community is necessary to integrate environmental programs and achieve multiple outcomes for land, water and biodiversity.

National Environmental Biosecurity Response Agreement (NEBRA)

Victoria is a signatory to the National Environmental Biosecurity Response Agreement (NEBRA). The NEBRA sets out emergency response arrangements, including cost-sharing arrangements, for responding to biosecurity incidents that primarily impact the environment and social amenities and where the response is for the public good.

A national biosecurity incident response under NEBRA would be considered for new incursions of invasive species in waterways if such incursions were assessed as being of national significance and the invasive species was likely to be eradicable.

Research and resources

Education and awareness-raising material for aquatic invasive species

We have created educational material on invasive species that affect waterways specifically for community and industry stakeholders.

Engaging with the community and industry is a fundamental component of the framework for managing invasive species in waterways.

Help stop freshwater pests in Victoria's waterways

Managing invasive species in wetlands

Invasive plants and animals are one of the main threats to wetland values. Visit managing wetlands for information on the impact of rabbits, foxes, pigs and carp on wetlands.

Further information on terrestrial and marine pests

Page last updated: 08/09/23