A strategy for dealing with invasive species in Australia

Our Work  |  Feral Animals

When it comes to invasive species, prevention is much easier and cheaper than cure.

That’s why we focus our efforts on stopping new invasive species from entering the country and preventing the spread of those weeds and pests that have already established a foothold in Australia.

We aim to:

  • Increase understanding by building government, industry and public awareness about the threats of invasive species to Australia’s native biodiversity.
  • Reform laws, policies and practices to increase the nation’s capacity to prevent the importation of more invasive species and to limit the establishment and spread of weeds and pests in Australia.
  • Protect Australia from the most dangerous invasive species by advocating for prohibitions, declarations, and control of particular species.
  • Build a community of invasive species advocates by working with our members, other environment and community groups, experts and decision-makers to build the momentum for reform.
  • Work at the cutting edge by identifying and raising awareness of emerging issues and keeping up with the latest science.

What are invasive species?

Invasive species are animals, plants and other organisms (exotic or native) that are introduced by human agency, directly or indirectly, to places outside their natural range where they reproduce and spread, often threatening indigenous species and compromising ecosystem functions.

Also on this page:

Our seven-year strategic plan

In 2016 we adopted a seven-year strategic plan. The plan sets out five priority areas for the organisation’s prevention and early action work which forms the majority of our efforts. It also explains the approach to our work seeking to eradicate, contain and control invasive species that have already arrived and established in Australia.

Our broader approach

In 2010 the Invasive Species Council described the approach we would use to reducing the impact on the environment from invasive species.

Our challenges

The threats: Invasive species are dire threats to Australian biodiversity. They have caused the greatest number of animal extinctions in Australia in modern times, and along with habitat loss are the major pressure on Australia’s thousands of threatened species and ecological communities. Looming climate change, the third major driver of biodiversity loss, will in many cases threaten species by exacerbating the impacts of invasive species. Invasive threats are escalating as new exotic species establish, as existing invaders spread, and as interactions with other threats intensify.

The solutions: The challenge for the Invasive Species Council is to persuade governments to adopt the reforms necessary to stop the invasives problem escalating: to prevent new invaders and eradicate or control existing invaders. To become a more effective advocate, we must build public support for reform.

Table 1: Invasion processes and management options
Table 1: Invasion processes and management options

Challenge 1: Reforming laws, policies and programs – reducing the threats of invasive species

Invasive species are what is known as a ‘wicked’ problem: complex with no total solutions, engendering value conflicts, and requiring multiple actions now to prevent damage that might not manifest until far in the future. There is need for reform at multiple scales and on multiple issues: to prevent invaders from entering Australia, to prevent their spread within Australia, to eradicate new invaders where possible and to control invaders that threaten biodiversity (see Table 1 and Table 3). It is a very complex policy area, encompassing state and federal laws and policies.

Challenges in this area include:

Prevention: There are numerous pathways for invasive species to enter Australia, through permitted or illegal introductions or accidental incursions. The pressure of global trade is immense, and trade is the main source of new invaders. Prevention often involves conflicts with commercial and social interests such as agriculture, horticulture, forestry, hunting, tourism, global trade and the pet industry.

Eradication: Few eradications have been attempted in Australia. The technical difficulty and costs of eradication increase with time, so rapid responses to new incursions are essential. Opportunities for eradication are being lost due to delay and lack of funding. There is often the potential for re-invasion after eradication, requiring constant vigilance.

Control: Funding for control programs is often inadequate, poorly targeted and short-term. Governments perceive invasive species as a huge never-ending drain on public purse and are reluctant to dedicate sufficient resources. Often resources are directed to popular and social issues rather than to priority biodiversity targets. Most biosecurity units are run by agricultural departments, which can bias outcomes towards agricultural interests.

Challenge 2: Mainstreaming invasives issues and building public support

The Invasive Species Council was established because the issue of invasive species was neglected within the environment movement, and this neglect is ongoing. While most Australians are aware that foxes, cats, cane toads and lantana are damaging invaders, they are much less aware of other invasive threats, the scale of the problem and that threats are escalating. The Invasive Species Council’s challenge is to build public concern about the problem in the wider community and to turn this support into pressure for reform.

Challenges in this area include:

Increasing understanding of the threats: The biology of invasive species is complex, encompassing thousands of species and numerous invasion pathways, with impacts often cumulative, insidious, and slow to develop. Apart from a few of the most severe threats, the numbers and impacts of most invasive species are poorly known (see Table 1).

Compared to the brutal immediacy to the environment of land clearing or construction of a new dam, invasive species can seem less threatening. It is difficult for non-specialists to imagine some invasive species as major threats: weeds in particular don’t excite the public imagination, being perceived more as an aesthetic or agricultural issue.

Most invasions are slow and may take decades or longer to have an impact, and the losses – the displaced or eliminated native plants and animals – are often difficult to detect. The Invasive Species Council needs to increase awareness of the biology and impacts of invaders.

Building support for action and promoting solutions: The Invasive Species Council needs to convert understanding of threats into active support for particular reforms, persuading potential allies and supporters that there is much that can be done to prevent new invaders and limit the harm caused by existing invaders. Because the problems are dire and numerous, there is the risk that the public will feel overwhelmed and powerless.

We need to shift public interest from infamous but intractable pests such as cane toads towards new and emerging problems with no public profile but better opportunities for intervention. We need to focus effort on practical solutions and early intervention. Challenges include that the language of invasives (a heavy use of war metaphors) and the necessity for large-scale killing can be off-putting, and that some control methods affect animal welfare.

Increasing the conservation priority of invasive species: Current conservation campaign foci and resources devoted to invasive species are disproportionately low. The Invasive Species Council seeks to build support within the environment sector – including NGOs, scientists and policy-makers – for reforms, and to increase the priority accorded to invasive species threats by environmental agencies.

Our opportunities

  • There are many practical actions that can be undertaken to protect biodiversity from invasive species. More can probably be achieved for conservation by action on invasive species than for other threats. Acting on invasive species is a vital part of climate change adaptation.
  • The benefit: cost ratio of preventions and eradications is very high, when action is taken at an early stage in the invasion process.
  • Some invasive species are economic as well as environmental threats, and are of concern to more than the conservation sector – an estimated 25% of costs of food for consumers are due to invasive species.
  • Scientists have been strong advocates in this area.

The harms caused thus far have been massive and serve as warnings for the future. There are many stories of great follies and some of outstanding successes. Learning from the past is a major theme.

Priority 1: Achieve law, policy and program reforms in high priority areas


  • prevention and eradication are more effective and cost-effective than control of an entrenched invader.
  • supports the need for transparent prioritisation of programs.
  • committed to prioritising on the basis of threat and feasibility of reform.


Table 2 below describes the detailed priority reforms sought.

Objective 1 Prevention

1.1 Prevention pre-border:

  • Precautionary federal biosecurity laws with strong environmental focus.
  • Risk assessment applied to new species and new varieties and genets of existing permitted species, and only low-risk new taxa permitted.
  • Taxa threatening to biodiversity removed from permitted lists.
  • High biosecurity standards for hull fouling and ballast water.
  • Strong surveillance and rapid response capacity for new incursions.

1.2 Prevention post-border:

  • White-list (permitted list) approach implemented nation-wide for non-native species.
  • Federal environmental regulation of some invasive species.
  • Foresighting capacity and response to emerging threats.
  • Reduced permitted lists, in particular for aquarium fish and plants.
  • Remove unsafe species from high-risk areas.

Objective 2 Eradication:

  • Well-funded eradication programs for environmental threats.
  • High priority eradications of particular species.

Objective 3 Control:

  • Well-funded long-term control programs for environmental threats.
  • Control of high-priority threats such as Phytophthora.
  • Climate adaptation programs prioritise invasive species control.

Priority 2: Build strong public support for effective action on invasive species


  1. Increase awareness of invasive species threats:
  2. Build support for solutions
  3. Increase priority within conservation sector:

Priority reforms needed

Table 2: Invasive species reforms needed


Objective 1: To stop new invasive threats

1.1 Pre-Border (national biosecurity)

Goal: To limit new invasive taxa entering Australia

Invasion stageTypeStatusReforms needed
Deliberate introductions of invasive speciesNew taxa (including hybrids & variants) proposed for importTremendous pressure from global trade. Australia generally takes a precautionary approach to new species, but there are limitations with risk assessments, including that new taxa (eg. new cultivars) of existing invaders are generally not assessed.Strong biosecurity laws that are precautionary, ensure rigorous independent risk assessment, and give high priority to protecting the environment and biodiversity.
WTO laws compatible with precautionary prohibition of taxa on environmental grounds (uncertain about the extent to which they need reform).
A biosecurity priority is to limit genetic variability of invasive species. Imports of new variants (including genets) of existing permitted species are subject to risk assessment and prohibited if they are likely to increase invasive risks in their own right or due to hybridisation with existing variants.
Permitted species that are invasive or potentially invasiveMany exotic plants and animals are permitted imports for historical reasons – they were already in Australia when quarantine was reformed in 1997. They have never been risk assessed. Many are invasive, and continued importation increases their threat. Permitted plants number 36,000.Permitted lists substantially reduced on basis of risk assessments to limit the importation of invaders and potential invaders – priorities include plants and fish. States/territories enact ‘official control’ over invaders to justify (in compliance with WTO rules) reduction of the federal permitted list.
Accidental introductionsHitchhikers & stowaways – usually with imported products or on ships.Rapidly increasing trade increases the risks of accidental introductions. The majority of marine invaders arrive on hulls or in ballast water. Invertebrates (eg. Asian honeybees) and vertebrates (eg. black-spined toads) arrive with commodities, eg. in containers, on products and in ships. Incursions are often detected too late for eradication or governments are slow to respond. Protocols for cost-sharing of responses to many environmental threats are lacking.Implementation of higher biosecurity standards for hull-fouling and ballast water.
Strong surveillance programs around high-risk pathways. Rapid response capacity to respond to new incursions, including effective cost-sharing arrangements between governments for environmental eradications. Work in countries of origin and along product supply chains to reduce risks. Resources focused on highest-risk pathways. Education about best-practice protocols to avoid accidental introductions.
Illegal introductionsSmuggled –travellers, postExtent is poorly known. Sales via the internet are increasing rapidly & are a significant risk.Risk-based monitoring and compliance regime and strong education programs.

1.2. Post Border (within Australia)

Goal: To limit introduction & spread of invasive taxa within Australia

Invasion stageTypeStatusReforms required
Deliberate legal spread or escape from cultivation or captivityPlantsExcept in WA, which requires risk assessment of new introductions, there is unconstrained movement of all plant species other than those on state/territory prohibited lists. Approx. 20 new species naturalising/year. No constraints on the planting of many serious weeds. New cultivars of existing weedy species could increase invasiveness. Many native plants shifted out of range are invasive or potentially invasive. Many more garden plants will escape in future unless removed. Climate change is likely to increase prospects of escape & spread (eg. garden plants in alpine areas & Wet Tropics). Abandoned agronomy experimental sites are high risk sources of new weeds.Harmonised white list systems adopted in all states/territories – no new releases unless assessed as low risk and sales/movement of existing species restricted to limit spread. Mandatory labelling of garden plants.
Federal listing & regulation of invasive species threatening to biodiversity under EPBC Act.
Foresighting to identify emerging and future threats, and policy responses to prevent threats such as weedy biofuels.
Strong duty-of-care and polluter pays provisions requiring people to take responsibility for escapes of invasive species.
Programs to remove unsafe species from high-risk and high conservation value areas (eg. garden plants from Wet Tropics, alpine areas and old agronomy research sites), taking into account the potential for spread under climate change.
Animals – vertebrates & invertebratesHigh risks include aquarium fish, deer from farms, animals from hunting properties and zoos, aquatic species from aquaculture.Species on current state/territory permitted lists for aquarium fish reduced. Education programs about safe ownership of fish (and other exotic pets).
Strong regulations and duty of care provisions to require safe containment of exotic animals (eg. on hunting properties, deer farms).
Prohibitions on release of exotic animals except if risk is negligible.
Accidental spreadHitchikers, stowawaysWeeds seeds spread through fodder distribution & movement of livestock & with vehicles. Hitchhikers (eg. tramp ants, toads) with commodities, eg. with timber, potplants and produce, or on cars & trucks. Diseases spread through aquaculture, nursery trade, pet trade.Enforceable & monitored protocols for high-risk pathways of spread. Education to prevent unsafe practices.
Strong surveillance & rapid response programs for new incursions, including weed spotter programs to involve the public.
Illegal spreadPlants & animals spread by hunters, hobbyists, ecoterrorists.Foxes illegally released in Tasmania, deer and pigs spread by hunters, aquarium fish released by pet owners release, deer released by failing deer farms. Release for commercial purposes (eg. bumblebees). Difficult to enforce laws.Strong laws & enforcement against illegal releases. Limit risk factors such as recreational hunting on public lands. Educational programs to discourage releases and promote public reporting.


Objective 2, 3: Remove & reduce the threat of existing invaders

2 Eradication from the Wild

Goal: Completely eliminate invasive taxa from all or part of Australia where feasible

Invasion stageTypeStatusReforms
Newly established/ limited spreadNewly established species likely to become invasive.> 20 new species naturalise each year. Very few eradications occur. Benefit: cost ratio of eradication at an early stage are very high. There has been a bias in eradication focus on species with economic impacts. Biggest eradication programs are foxes in Tasmania & red imported fire ants in Qld.High priority accorded to eradicating environmental weeds and pests before they spread. Well-funded eradication programs based on transparent prioritisation and with a strong focus on environmental threats. Effective cost-sharing arrangements between governments for eradication of high-priority environmental threats, including under climate change.
High priority eradications include yellow crazy ants & Asian honeybees in Qld, foxes in Tasmania, some deer populations.
Entrenched invasionsInvaders threatening biodiversityIt is usually impossible to eradicate an entrenched invader, but there has been increasing success on islands.Eradication programs for high-priority threats where prevention of re-invasion is feasible, including on islands.

3 Control Invasive Species in the Wild

Goal: Reduce the range, density and harm caused by existing invasive species threatening the environment

Invasion stageTypeStatusReforms required
Entrenched invasions threatening biodiversityWeeds, pests & diseases threatening biodiversityMany invasive species severely impacting on biodiversity. Many threatened species and ecological communities at risk. Control programs greatly underfunded, often short-term, localised and ineffective. For some species, the only prospect for control is biocontrol agents.Well-funded long-term control programs with transparent, science-based prioritisation. Landscape-scale, mutli-species control programs with outcomes monitored.
Well-funded research into effective and humane control methods, including biocontrol. Establish weeds research centre. Maintain CRC for invasive animals.
Control programs for high priority targets (currently receiving inadequate attention) include phytophthora, tramp ants, deer, horses, goats, numerous weeds (eg. tall wheat grass).
Control programs are a high priority for climate change adaptation.

Note: Current at 2010. Today, little has changed and these reforms remain just as urgent. Any reform that is achieved will be noted. Also see our achievements.

Invasive species in Australia

What do we know about the invasive species already in Australia?

Table 3: Invasive species in Australia – numbers, pathways and costs

 Plants (vascular)Vertebrates (not fish)Fish (freshwater)Invertebrates (terrestrial & freshwater)Marine organismsMicro-organisms & fungi
Introduced – exotic species>30,000~650 (including in captivity)~1200ThousandsThousandsThousands
Introduced – native species>12,000Unknown>50UnknownUnknownUnknown
Major pathways of introductionMostly deliberate: horticulture & agricultureMostly deliberate: agriculture, hunting, pets, acclimatisationMostly deliberate: aquarium trade, fishing, ballastMostly accidental: with traded products, on wind, water & other organismsMostly accidental: hull fouling, ballast water, aquacultureMostly accidental: with traded products or with introduced organisms
Invasive with environmental impacts>1,000~30~10UnknownUnknownUnknown
Costs(mostly agricultural)>$4 billion>$1 billionUnknownUnknownUnknownUnknown


Plants: (1) Department of Agriculture, Fisheries and Forestry (2009) Census of Cultivated Plants; (2) Downey, PO, Scanlon, TJ and Hosking, JR. (2010) Prioritising alien plant species based on their ability to impact on biodiversity: a case study from New South Wales. Plant Protection Quarterly 25(3), 111-126; (3) Randall R. (2007) The introduced flora of Australia and its weed status. CRC for Australian Weed Management, Adelaide, Australia: (4) Sinden J, Jones R, Hester S, Odom D, Kalisch C, James R, Cacho O. (2004) The economic impact of weeds in Australia, CRC for Australian Weed Management, Adelaide; (5) Navie, SC and Adkins, SW (2008) Environmental Weeds of Australia. DVD-ROM. The University of Queensland.

Vertabrates: (6) McLeod R. (2004) Counting the Cost: Impact of Invasive Animals in Australia 2004. Cooperative Research Centre for Pest Animal Control, Canberra; (7) Tracey J, Bomford M, Hart Q, Saunders G and Sinclair R. (2007). Managing Bird Damage to Fruit and Other Horticultural Crops. Bureau of Rural Sciences, Canberra; (8) Bomford, M, Hart, Q. (2005). Non-indigenous vertebrates in Australia. In Pimental, D. (ed.), Biological Invasions: Economic and Environmental Cost of Alien Plant, Animal and Microbe Species. CRC Press, London; (9) Bomford M, Hart Q. (2002) Non-indigenous vertebrates in Australia. Biological Invasions – Economic and Environmental Costs of Alien Plant, Animal and Microbe Species. Pimental D (ed), CRC Press, New York.; (10) Forsyth, D. M., R. P. Duncan, M. Bomford, and G. Moore. (2004). Climatic suitability, life-history traits, introduction effort, and the establishment and spread of introduced mammals in Australia. Conservation Biology 18:557-569; (11) Vertebrate Pest Committee (2007) Australian Pest Animal Strategy – A national strategy for the management of vertebrate pest animals in Australia. Department of the Environment and Water Resources, Canberra.

Fish: (12) Lintermans, M. (2004). Human-assisted dispersal of alien freshwater fish in Australia. New Zealand Journal of Marine and Freshwater Research. 38:481-501; (13) McNee, A. (2002). A national approach to the management of exotic species in the aquarium trade: An inventory of exotic freshwater fish species. Canberra, Bureau of Rural Sciences; (14) West P, Brown A and Hall K. (2007) Review of alien fish monitoring techniques, indicators and protocols: implications for national monitoring of Australia’s inland river systems. Invasive Animals Cooperative Research Centre, Canberra.

Invertebrates: (15) Tasmanian Planning Commission. (2003), State of the Environment Report: Tasmania 2003, Tasmanian Planning Commission. http://soer.justice.tas.gov.au/2003/bio/4/issue/23/index.php; (16) Greenslade, P. (1993)Threats from introduced invertebrates. Newsletter on biological diversity conservation actions. Biolinks No. 4.

Marine organisms: (17) CRC Reef Research Centre. (n.d.) Introduced marine species. CRC Reef Research Centre: Discover the reef, website, CRC Reef, Townsville, Qld, www.reef.crc.org.au; (18) Hayes, K, Sliwa, C, Migus, S, McEnnulty, F, Dunstan, P. (2005), National Priority Pests: Part II ranking of Australian marine pests, Department of the Environment and Heritage, Canberra, & CSIRO Marine Research, Hobart.