The reduction in the biodiversity of Australian native fauna and flora due to the red imported fire ant, Solenopsis invicta (fire ant)

Advice to the Minister for the Environment and Heritage from the Threatened Species Scientific Committee on Amendments to the list of Key Threatening Processes under the Environment Protection and Biodiversity Conservation Act 1999

1. Name and description of the threatening process

Name

Nominated name: 'The reduction in the biodiversity of Australian native ground fauna due to the red imported fire ant, Solenopsis invicta Buren (fire ant).'

It is recommended that the name of the threatening process be expanded to include the threats of fire ants to native flora. Fire ants impact on plant species through direct grazing on seedlings but perhaps more significantly via indirect effects due to impacts on insectivorous species and ecological processes such as seed dispersal, pollination and germination.

Whilst in the United States fire ants have been found up in trees, for example, in pecan orchards, in Australia they are showing limited arboreal tendencies and have only been found at a height of 0.5m above the ground, even in the most infested sites. The term 'ground' has been used in the description of the process, although it must be recognised that bird species that have ground-based feeding habits and species that occupy the zone within one metre above ground may also be at risk.

The potential impacts of the fire ant in Australia are essentially unknown and are extrapolated from the impacts of the fire ant infestation in the United States. Therefore the name should not exclude some potential impacts of the red imported fire ant in Australia.

TSSC therefore recommend the threatening process be re-named:

'The reduction in the biodiversity of Australian native fauna and flora due to the red imported fire ant, Solenopsis invicta (fire ant).'

Description

Components, scope and scale of the key threatening process

Characteristics of fire ants

The Red Imported Fire Ant (fire ants) is a small colonial ant that is a native to Paraguay and the seasonally flooded Pantanal region of southern Brazil in South America. Fire ants are one of several closely related Solenopsis species native to this area and its natural distribution appears to be regulated by competition from these species as well as a suite of endemic predators and pathogens.

Fire ants are aggressive generalist foragers that occur in high densities. Fire ants workers sting relentlessly when their mound is disturbed. They are effective at foraging and recruitment, which makes them highly competitive and very effective at resource defence. Fire ants sting in synchrony initiated by an alarm pheromone and the stings result in painful pustules, which may take weeks to heal. Its stinging ability allows it to repel larger vertebrate competitors from resources. People, stock, wildlife and domestic pets are readily stung if they disturb a nest and this can induce anaphylactic shock in sensitive individuals. Fire ants are opportunistic feeders that are omnivorous and predate on invertebrates, vertebrates, and plants, destroy seeds, harvest honeydew from specialised invertebrates and also scavenge.

Fire ants colonies can contain a single queen (monogyne) or multiple queens (polygyne) with between 200,000 and 400,000 workers. The primary threat from fire ants is a consequence of its aggressive territorial and feeding behaviour. Monogyne colonies vigorously defend territory around the colony and achieve a density of up to 680 mounds per hectare whereas polygyne colonies allow workers to move between colonies allowing mound densities of up to 2,600 mounds per hectare. New colonies are formed by flights of winged ants leaving the colonies. Both types of colonies are also able to disperse on flowing water, and thus have an advantage in areas of seasonal flooding. When waters rise, they float as a mat of ants, surviving for weeks until the waters recede or they drift ashore.

Fire ants were introduced into the United States in the late 1930s where it has become an aggressive, invasive species over much of the southern United States and parts of California. Studies in North America have found that fire ants largely replace the native invertebrate predatory species, becoming the dominant predator and disrupting invertebrate-based food webs. Fire ants have the potential to threaten the survival and abundance of native fauna, particularly invertebrate species. Experience from the United States suggests that the fire ants may become very widespread over a period of time and may seriously threaten communities of small ground animals, especially in disturbed environments. Fire ants have colonized over 275 million acres of the United States since its introduction.

The worldwide distribution of fire ants suggests that they occur in most habitats except swamp and dense forest. The species occurs mostly in areas of disturbance such as lawns, pastures, roadsides, and agricultural lands or open natural areas such as grasslands or open forests.

Fire ants in Australia

Fire ants were discovered at two separate sites in Brisbane, Queensland in February 2001. The monogyne form occurs at the Fisherman's Island container wharf in Moreton Bay. The polygyne form has been found over a large area of the south-western suburbs of Brisbane centred on Wacol. Although the infestation is believed to be confined to the Brisbane area at this stage, fire ants have the potential to invade much of Australia.

Predictive studies have been initiated by the Department of Primary Industries, Queensland on the modelling of fire ants habitat preferences and estimations of rate of uncontrolled spread. These studies showed that fire ants have the potential to occupy most arable land areas on mainland Australia within the next 30 years.

The CSIRO Entomology CLIMEX model allows users to examine the role of climate in pest ecology and is used widely in pest risk analysis, biological control, integrated pest management and climate change research. The CLIMEX model has been used by the CSIRO to study the potential distribution of fire ants in Australia, based on its known temperature and moisture requirements. The main limiting factors were found to be cold and dryness. Fire ants are tolerant of high temperatures (up to 40°C) and highly adapted to wet conditions. The results show that fire ants are capable of inhabiting most of coastal eastern and northern Australia. After making allowances for the availability of supplementary moisture from irrigation, CLIMEX predicts that fire ants have the potential to inhabit even wider areas of Australia. Apart from the desert areas, the high altitude locations on the Great Dividing Range and most of Tasmania, much of the Australian continent is vulnerable to this pest.

The current threat from the fire ant is to the native flora and fauna of southeast Queensland because of the current known distribution of the pest. However, the fire ant could cause significant damage to the biodiversity of other areas throughout Australia if it spreads either naturally by winged ant dispersion or by human assisted means.

Process and resultant interactions and effects: evidence from the United States

Fire ants were introduced into the United States in the late 1930s where they have become a major pest. Evidence from the United States demonstrates the effect that fire ants have had on biodiversity. The polygynous form of fire ants, that is present in Australia, is reported to be especially devastating to fauna, due to its occurrence in high densities. In the United States it has been shown that as the polygyne form invades, the diversity and abundance of native arthropods and even vertebrates have been greatly reduced.

The fire ant is a generalist predator that affects all levels of species within the food chain. Its negative impacts on numerous invertebrates and vertebrates have been well documented. They reduce species abundance and diversity by displacing native ant species, preying on any arthropods unable to defend themselves and can attack and sometimes kill ground inhabiting vertebrate species such as birds, reptiles and small mammals. Fire ants also damage plants by eating fruit, seeds, tunnelling into stems, ring barking seedlings and feeding on nectar.

Evidence from the United States suggests that fire ants are able to consume insects at any stage of development from egg to adult, feed on predatory arthropods such as spiders and on other invertebrates especially those that are solitary. Because of their prevalence and efficiency, fire ants may control the balance of species within an invertebrate community more than other arthropod predators, which can lead to an overall decrease in insect biomass. This may indirectly affect other insectivorous species and threaten ecological processes such as seed dispersal, pollination and germination.

Fire ants affect native vertebrate wildlife in the United States by consuming soft-shelled eggs, hatching, newborn and dependent young and sometimes adults of some species. Fire ants have been reported to attack the eggs or nestlings of several species, including turtles, lizards and water birds and are associated with a decline in nesting success of Cliff Swallows and populations of Northern Bobwhite Quail.

In the United States, fire ants are reported to negatively affect small mammal densities. Species that are stung by fire ants may be killed outright and those stung non-lethally may exhibit reduced weight gain or survival, loss of digits, obscured vision or blinding and an inability for normal movement. Species such as small mammals that already have a reduced home range due to threats by other introduced predators and land clearing could be put at greater risk through pressure on habitat use from fire ant infestations. The debilitating effects from fire ant injury are not species specific.

2. How judged by TSSC in relation to the Environment Protection and Biodiversity Conservation Act 1999 criteria

Section 188(4) of the Environment Protection and Biodiversity Conservation Act 1999 states:

A threatening process is eligible to be treated as a key threatening process if:

  1. it could cause a native species or an ecological community to become eligible for listing in any category, other than conservation dependent; or
  2. it could cause a listed threatened species or a listed threatened ecological community to become eligible to be listed in another category representing a higher degree of endangerment; or
  3. it adversely affects 2 or more listed threatened species (other than conservation dependent species) or 2 or more listed threatened ecological communities.

A. Could the threatening process cause a native species or an ecological community to become eligible for listing in any category, other than conservation dependant? And

B. Could the threatening process cause a listed threatened species or a listed threatened ecological community to become eligible to be listed in another category representing a higher degree of endangerment?

The discussion of Criteria A and B have been combined as evidence for both criteria has been extrapolated from United States examples and the potential for effects of fire ants will be broadly based on groups of species. By examining the impacts that fire ants have had on species in the United States and extrapolating the evidence to Australian species that occupy the same niche, the potential effects on individual species can be estimated and predicted. The ability of fire ants to have an impact on listed threatened species in Australia will depend on its ability to expand its range sufficiently to encompass such threatened species, and its ability to establish at high density in natural habitats.

Impacts on ecological communities

This assessment has concentrated on the potential effects of fire ants on threatened species as effects on Australian ecosystems and ecological processes can not be easily extrapolated from evidence in the United States and therefore the impacts of fire ants on Australian ecological communities and the potential cascade effects in natural environments are difficult to predict.

Impacts on invertebrates

Fire ants feed on a wide variety of invertebrates in the United States. Evidence from the United States suggests that fire ants affect species richness and the abundance of invertebrate individuals in an area and will attack, kill and consume those invertebrates that do not defend themselves adequately or escape. They have also been shown to prey on all swallowtail butterfly life stages (eggs, larvae and pupae).

In Australia, the Bathurst Copper Butterfly (Paralucia spinifera), which is listed as vulnerable could potentially be at risk, along with an unknown range of other butterfly species. Australian invertebrates that are particularly at risk are flightless carabid beetles, localised land snails, native earthworms and mygalomorph (trap-door) spiders. These are at risk as they are solitary, have few defences and are flightless.

Ants are a fundamental component of Australian ecosystems as a food source and for their role in ecological processes. The dispersal and survival of seeds of many Australian plants is intimately tied up with the corresponding ant fauna of the region. This dispersal mechanism is very widespread in the Australian flora, with at least 1000 species having their seeds dispersed in this way. Fire ants have been shown to relocate and eat seeds, which alters the ratios of the various seeds and the distribution of seeds available to develop, which can cause major changes in an ecosystem. Disturbing the assemblage of invertebrates and vertebrates in an area, may also ultimately affect plant assemblages as well. There are currently no nationally listed threatened ant species under the EPBC Act.

Impacts on vertebrates

Evidence from the United States demonstrates that fire ants do not only impact on native vertebrate populations through direct predation. Other impacts include reduced survival and weight gain resulting from fire ant stings, alteration of feeding patterns and habitat use by species to avoid fire ants, reduced food availability from fire ant predation, effects on the food chain, and ecosystem changes resulting from the impact of fire ants on ecological processes. Small vertebrates can be blinded, lose digits or suffer from infection as a result of fire ant stings. Where the optimal habitat of a native species and high fire ant densities occur together, vertebrates tend to shift to areas of less suitable habitat, which may have a negative impact on vertebrate populations. As a consequence of reduced food availability due to the presence of fire ants, insectivorous vertebrates may be expected to both increase the foraging area and decrease recruitment. In the extreme case of food specialization where the food source is affected negatively by fire ants, population collapses may occur as is occurring with the Texas horned lizard, Phynosoma cornutum (Wojcik 2001) and may cause problems in areas where insectivorous bats occur.

In the United States, fire ants prey on nesting reptiles such as lizards, turtles, snakes and alligators, which result in a decrease in hatchling release rates and surviving hatchlings can suffer from poor weight gain and reduced survival rates. Declines in the Peninsular Intergrade Kingsnake have been reported in the United States, which coincided with the invasion and rapid population rise of polygynous fire ants. When fire ants are present in nests of the alligator Alligator mississippiensis, hatching alligator young are subject to predation and reduced weight gain from stings.

In Australia there are no nationally listed threatened crocodylus species, however there are several nationally listed threatened lizard species (eg various legless lizards, Delmar sp) that may be susceptible. Evidence from the only study in Australia to date has demonstrated that scinid lizards are adversely affected by the presence of fire ants (Nattrass and Vanderwoude, 2001).

The impacts of fire ants on fresh and saltwater turtle species in the United States have been well documented. In Australia, the Loggerhead turtle (Caretta caretta) is a nationally listed threatened species whose rookery is located less than 400 kilometres north of the current fire ant infestation in Brisbane. If the fire ant is able to spread in Australia to the habitats of other nationally listed saltwater turtles (eg Green Turtle (Chelonia mydas), Leathery Turtle (Dermochelys coriacea) and Pacific Ridley (Lepidochelys olivacea) or freshwater species (eg Bellinger River Emydura (Emydura signata), Namoi River Elseya (Elseya sp.) they could be at risk from the impacts of fire ants.

Whilst there is only limited evidence from the United States reporting fire ant induced mortality of amphibians, a number of amphibians with full or partial terrestrial development in Australia may be at risk. These species include frogs in the genera Philoria and Pseudophyrne of which some species are nationally listed and occur in habitats within the potential distribution of fire ants (eg Magnificent Brood Frog, Northern and Southern Corroboree Frog and Baw Baw frogs).

The impact of fire ants on bird species have been investigated in the United States and it has been shown that hatchlings of species such as water birds, quails and swallows can be affected. Chicks of Northern Bobwhites (Clinus viginianus) are susceptible to fire ants. The decline in numbers of Northern Bobwhites has been linked largely to declines in habitat availability and quality. As these disturbed areas are rapidly colonised by fire ants the impacts are additive. The impacts of the fire ants are both from direct injury, altering their habitat use and as a result of the decrease in abundance of invertebrates, which is an important component of Northern Bobwhite diets.

Bobwhite quail reach an adult body weight of 170-212g and adult body length of 23-28cm which is slightly larger than Australian nationally listed quail species that occur in Queensland such as Black-breasted Button Quail (Turnix melanogaster), Painted Button Quail (Turnix varia scintillans). Australian species that occur in potential fire ant habitat such as the Malleefowl (Leipoa ocellata) and Plains Wanderer (Pedionomus torquatus) are currently listed as vulnerable as they are at risk from predation by foxes, cats and habitat alteration. Further pressures on recruitment of these species from impacts by fire ants may further endanger these species.

Australian listed and unlisted ground-nesting bird species are susceptible to direct impacts by fire ants on eggs and hatchlings. An analysis is provided in Attachment (i), which outlines the ground-nesting birds species that occur in potential fire ant habitat and therefore are potentially at risk from the impacts of fire ants. Whilst this may be a preliminary analysis, it highlights the range of Australian native bird species that have the potential to be affected by the fire ant. There are also potential impacts on birds such as the Fairy-wrens (Family Maluridae), which have ground based habits and feeding requirements.

Fire ants impact negatively on small mammal densities in the United States as a result of direct (eg impacts from fire ant attacks resulting in death or injury and reduced weight gain) and indirect means (eg behavioural changes and changes to food availability, especially for insectivorous mammals such as bats). It is difficult to identify specific mammals or groups of mammals that will be affected by impacts of fire ants, as mammals are generally high in the food chain, so it is likely that any disruption in ecosystem processes in infested areas will inevitably affect mammal species. This is in addition to any direct impacts on mammal species and their young.

Impacts on plants

The species-specific relationship between many Australian terrestrial orchids and their insect pollinators are well documented and many of the pollinating insects are ground-breeders. The effect of fire ants on pollinators, ground-dwelling native bees and Thynid wasps is potentially devastating for the natural fertilisation of flowers and subsequent seed production of orchids. Therefore in Australia many complex plant-invertebrate and invertebrate-invertebrate relationships may be seriously disrupted by the establishment of fire ants.

Orchid species that occur within the South-east Queensland region in the vicinity of the current fire ant infestations include the Leafless Tongue-orchid (Cryptostylis hunteriana), which is nationally listed as vulnerable and the nationally listed endangered swamp orchid species (Phaius australis and Phaius bernaysii). In addition there are many orchid species that are nationally listed and occur in areas of potential fire ant habitat.

Conclusion to A: Based on the information provided and summarised above, the TSSC consider that the threatening process:

  • has the potential to cause a number of native plant and animal species to become threatened

The threatening process could cause a number of native species to become eligible for listing as threatened, and is therefore eligible under this criterion.

Conclusion to B: Based on the information provided and summarised above TSSC considers that the threatening process:

  • has the potential to effect a number of animal and plant groups. These include nationally listed species that occur in Queensland such as the Loggerhead Turtle (Caretta caretta), Button Quail (Turnix melanogaster) and Painted Button Quail (Turnix varia scintillans).
  • If further fire ant infestations occur, the listed species that could be at risk within the area of potential fire ant habitat include the Bathurst Copper Butterfly (Paralucia spinifera), various legless lizards (Delmar species), listed saltwater turtles such as Green Turtle (Chelonia mydas), Leathery Turtle (Dermochelys coriacea) and Pacific Ridley (Lepidochelys olivacea) or freshwater species (eg Bellinger River Emydura (Emydura signata), Namoi River Elseya (Elseya sp.)). Listed frogs in the genera Philoria and Pseudophyrne of which some species are listed (Magnificent Brood Frog, Northern and Southern Corroboree Frog and Baw Baw frogs). The nest sites of the nationally listed Malleefowl (Leipoa ocellata) and Plains Wanderer (Pedionomus torquatus) could also be threatened by fire ants.

The threatening process could cause listed threatened species to become eligible for listing in another category representing a higher degree of endangerment, and is therefore eligible under this criterion.

C. Does the threatening process adversely affect 2 or more listed threatened species (other than conservation dependent species) or 2 or more listed threatened ecological communities?

Fire ants were discovered in February 2001, although it is uncertain how long fire ants have been in Australia. The only Australian study reported to date on the impact of the fire ants on biodiversity in a Brisbane forest remnant (Natrass and Vanderwoude 2001).

Although this study lacks replication of sites and a lack of baseline data at the fire ant infested site, the findings suggest support for previously reported accounts of biodiversity losses and impacts of fire ants on vertebrate and invertebrate life-forms in the USA. The findings of the Brisbane study showed that at the fire ant infested site there was low ant diversity and the complete absence of scinid lizards relative to other similar sites in Brisbane, which could not be explained by any observed biotic or abiotic variable. Ants form a significant part in the diet of most terrestrial skinks, vigorous defence mechanisms of the fire ant may be turning predator into prey during interactions between the native skink and this exotic ant. Ant species diversity at the infested site was more than half of the uninfested site. Those species recorded at the infested site were either 'weedy' opportunists (e.g. Ochetellus glaber, Paratrechina spp.) or arboreal species such as Polyrhachis.

No nationally listed threatened species were investigated in the Brisbane study. Due to the paucity of biodiversity research currently developed it is not possible to determine if the current infestation is adversely affecting any listed threatened species. The fire ants infestation does not currently occur in any nationally listed ecological communities.

Conclusion: Based on the information provided and summarised above TSSC considers that the there are currently no studies available which evaluate the effect of fire ants on listed species or ecological communities. Therefore the threatening process is currently not eligible under this criterion.

Conclusion - The threatening process meets s188(4)(a) and s188(4)(b) of the EPBC Act. The threatening process could cause native species to become listed as threatened and could cause listed threatened species to become listed in another category representing a high degree of endangerment. There are currently no studies available, which document the effect of fire ants on nationally listed threatened species or ecological communities, however this status is dependent of whether the current infestation is eradicated and whether further infestations occur in other areas of Australia.

3. Threat Abatement Plan

Current situation and control activity

Currently a major eradication program is being implemented in an attempt to eradicate fire ants from the infestation in the Brisbane area. The Queensland Department of Primary Industries (QDPI) is planning to treat every property in the fire ant infested area - around 70,000 homes- four times each year for three years. If the distribution of the fire ants can be confined to this area then eradication is possible; however if only a few colonies remain untreated, the mating flight dispersals throughout spring, summer and autumn will continually extend the core distribution. This is in addition to the problem of human-facilitated spread, and whilst there is a high level of awareness of this species in the current core distribution area, there is not such an awareness nationally which leads to the possibility of satellite communities developing undetected for a number of years (as with the current Brisbane population which may have been introduced 5-8 years ago).

The operational management of the fire ant eradication campaign is undertaken by the Fire Ant Control Centre (FACC), which is funded jointly by the Federal government and all Australian states. QDPI is the lead agency responsible for implementing the fire ant eradication program and associated research. The eradication program is being overseen nationally by the Primary Industries Standing and Ministerial Councils (PISC and PIMC), through the Consultative Committee for Response to Exotic Pests and the Scientific Advisory Committee (both made up of technical experts). These Committees initially examined the infestation in Brisbane and following a visit and advice from fire ant experts from the United States, concluded that provided fire ants were contained to a relatively small area in Brisbane, that eradication would be possible.

The control program seeks to contain the spread of fire ants and to poison the existing colonies. The program includes treating the entire infested area with bait formulations containing insect growth regulators, which are supplemented with individual applications of pesticides for nuisance mounds. The extremely high fecundity and rapid maturity of fire ants make it necessary for control measures to be highly lethal if they are to be effective. The chemicals used in the baits are hydramethylnon (metabolic growth inhibitor-amdro) and S-methoprene (insect growth regulator). Chemical control is not specific to fire ants and can control other invertebrate species, leaving areas depleted of invertebrate fauna. As fire ants are effective recolonizers (especially in disturbed habitats), they can rapidly recolonize previously poisoned areas without any obstacles to colony establishment and growth.

The principal means of transport of queens is in soil and landscaping products such as mulch, old timber rails and pot plants. There is substantial trade of nursery plants from south-eastern Queensland to southern markets particularly during spring and summer months. The average temperature profile suggests that conditions are well-suited to the survival of fire ants in such transport of nursery goods (Jacobi and Wong 1996). In the United States, quarantine has reduced the rate of fire ant spread via nursery stock, but nursery stock and other human modes continue to be important means of range expansion for this species.

The Queensland Department of Primary Industry has declared a Pest Quarantine Area around Brisbane to prevent the movement of materials from infested locations and the NSW Agriculture have declared the 'Red Imported Fire Ants' a notifiable pest requiring reporting if discovered in NSW. Businesses operating in the treatment zone for the fire ant eradication campaign with an approved risk management plan are able to display a new official sign to reassure their customers that they are not spreading the exotic pest.

Incursions of fire ants outside the Brisbane area

To date there have been two incidents where fire ants have been detected and eradicated outside of Queensland. The first incursion was when a 'patch of soil' was discovered on a shipping container of widgets from the United States. AQIS assistance was requested by the port authorities in Melbourne and the 'soil' was discovered to be a fire ant colony and was quickly destroyed. The second incident occurred when a truck driver backfilled his load with palms from Queensland and transported them to the Dandenongs just outside of Melbourne. The palms harboured fire ants, which stung the people unloading the plants. The area was poisoned and the fire ants controlled.

Potential scope for a National TAP

A nationally focused TAP could facilitate the organisation of activities at a national level that are not captured by the current eradication program. A national TAP should not duplicate the activities and processes already underway in Queensland to eradicate the fire ant.

The current eradication program is managed via a high level steering committee, is advised by a scientific assessment panel and is monitored by a national group of experts. While the on-ground eradication process is well-developed and should continue, a national TAP could provide additional focus on the threat to biodiversity from fire ants and ensure that the eradication program is successful in the long term.

A national TAP should focus on long-term activities such as prevention of further outbreaks in Australia via introductions from Queensland or overseas, establishment of monitoring and border control for fire ants and public and State agency information and education. The TAP should also consider aspects such as illegal and unplanned entry of fire ants from overseas as well as mechanisms to reduce spread within the country. The TAP would not cover legal imports of fire ants for scientific purposes as such entry is subject to import risk analysis.

Current surveillance and monitoring at the Queensland border, mainly relates to nurseries and those involved in the transport industry. There is a need for nation-wide public education and monitoring to be able to identify the species in the event of new occurrences outside of Queensland. The TAP would ensure that activities such as public education, surveillance and monitoring, quarantine and border control, and development of contingency plans in the States and Territories were coordinated at national level. The TAP would not duplicate current management of actions where management systems already occur, such as quarantine and border control activities, but facilitate information transfer between the relevant management agencies.

Components within the TAP

The TAP could include the following actions:

  • development of protocols for detecting new infestations with readily available techniques to rapidly eradicate small infestations once they are detected. For example bait monitoring systems could be established near infested areas and a national process of identification of ant samples with suitably trained scientists
  • public education to increase awareness of fire ants and procedures for the public if they suspect an incursion. Public outreach programs could be used to ensure public involvement in control programs
  • national awareness program of high risk materials and processes to regulate (as currently occurs in Queensland)
  • There should be measures developed and established to prevent reentry and establishment of the fire ant in other areas. If the current program is successful in eradicating the fire ants, the possibility of a repeat incursion of the ant into Australia remains an ever-present threat.
  • Establishment of a bait monitoring system in infested areas and where fire ants are detected replace monitoring baits with poison baits.
  • Contingency plans need to be development in other states. The ability of other State agencies to cope with new outbreaks has yet to be tested. They could easily be overwhelmed with multiple outbreaks however contingency planning may assist in preparing States for rapid implementation of control processes.
  • There need to be proper border protection policies developed and nationally agreed processes with regards to interstate transport of goods and fire ant quarantine to minimise the spread of ants into and within Australia. A national TAP will assist with the maintenance of funding and political will to guarantee that funding will allow potential for complete eradication.

In the event that the eradication program in Queensland is not successful, then it may be appropriate for the TAP to also consider a number of additional actions:

1) Assist with the co-ordination of funding issues to control the Brisbane infestation, given the potential for spread throughout much of Australia and associated impacts and ongoing control costs. This is particularly the case not only with regards to funding for control efforts but also for research into the effects of fire ants on Australian species and ecosystems and into effective eradication and control technologies in Australian conditions.
2) If the eradication attempt is subsequently abandoned, the focus should shift to reducing the rate of spread with a national fire ant colony location reporting database and high-level chemical control in key areas to reduce impacts.

Effective use of threat abatement planning

Fire ants belong to a group of ants called tramp ants, which are inherently invasive and ecologically damaging species. There are other species of 'tramp' ants already in the country and many others with the potential to be invasive if they are imported. These ants have characteristics that make them highly invasive. They are very aggressive and competitive so that they are able to dominate food sources, are easily dispersed by human activities and have the capacity to have 'supercolonies' with multiple queens that can allow rapid and extensive colonisation.

Other tramp ants include the Crazy Ant, Big-headed ant, Little Fire Ant and Argentine Ant. The crazy ant is causing major problems on Christmas Island and a population also exists on the mainland. The crazy ant is listed in the '100 of the World's Worst Invasive Alien Species' list, which is published by the Invasive Species Specialist Group of the Species Survival Commission of The World Conservation Union (IUCN). The Big-Headed Ant is impacting on biodiversity (especially native ants) in the Northern Territory, including the World-Heritage listed Kakadu National Park. The Argentine Ant occurs in cooler parts of Australia and is known to cause damage to native plants by interfering with the germination and survival of young plants. Argentine Ants can also reduce the numbers of many native ants near their nests by dominating food sources and preventing other ants from feeding or nesting.

Mitigation activities and processes for the control of the tramp ant species noted above tend to be consistent. Therefore a TAP could be developed to encompass all tramp ant species that are relevant to Australia and which have the potential to impact on Australia's biodiversity. This comprehensive approach would ensure a more effective and efficient use of resources in threat abatement.

The focus of such a TAP would include increasing public awareness of the impacts and identification of tramp ants; reducing the rate of movement of more widely established tramp ant species around Australia (including early eradication of new outbreaks); and barrier control to prevent new species entering the country. Many of the impacts of tramp ants are insidious and do not attract much public attention, particularly where they affect invertebrates rather than more high-profile vertebrates. Fire ants may be used to provide profile to the tramp ant issue in general.

Conclusion

A Threat Abatement Plan that mitigates the effect of fire ants by ensuring that activities such as public education, surveillance and monitoring, quarantine and border control, and development of contingency plans in the States and Territories are coordinated at national level is considered to be a feasible, effective and efficient way to abate the process.

Mitigation activities and processes are similar for the mitigation of fire ants as well as other invasive tramp ant species that also impact on biodiversity. Therefore development of a TAP which aims to abate the impacts of invasive tramp ant species, which include the fire ant would increase the efficiency and effectiveness of the TAP.

4. Recommendations

TSSC recommends that:

  1. The list referred to in section 183 of the EPBC Act be amended by including in the list as a key threatening process: 'The reduction in the biodiversity of Australian native fauna and flora due to the red imported fire ant, Solenopsis invicta (Fire ant)';
  2. The development of a threat abatement plan, which provides a national framework to mitigate the potential impact of the group of ants known as tramp ants (including the fire ant), is considered to be feasible, effective and efficient way to abate the impacts of these species. This TAP should not duplicate activities already underway in Queensland, but focus on actions such as public education, surveillance and monitoring, quarantine and border control, and development of contingency plans in the other States and Territories.
Attachment i) A preliminary analysis of Australian bird species that are potentially at risk from the direct impacts of fire ants and occur in potential fire ant habitat.
Common name Species Distribution Reasons for risk to fire ants
Endangered bird species
Southern cassowary Casuarius casuarius johnsonii Northern Qld Ground-nesting, within climatic range of fire ants although uncertain as to the incursion by the ants into the rainforest habitat
Eastern Bristlebird Dasyornis brachypterus SE Qld, NSW, Vic. Nest usually near the ground in clumps of grass or small shrubs.
Star Finch (eastern) Neochmia ruficauda ruficauda Qld, NT, WA Nests in grass tussocks.
Night Parrot Pezoporus occidentalis SW Qld, SA Ground-nesting.
Buff-breasted Button-quail Turnex olivei Northern Qld Ground birds that live in grasslands (open habitat).
Golden-shouldered Parrot Psephotus chrysopterygius Northern Qld Nests in termite mounds, uncertain impacts
Gouldian Finch Erythrura trichroa Northern Qld, NT, WA Nests in termite mounds, uncertain impacts
Western Whipbird (western heath) Psophodes nigrogularis nigrogularis WA Nests less than 1 metre above the ground, nests are shallow, cup-shaped and low to the ground.
Western Ground Parrot Pezoporus wallicus flaviventris WA Ground-nesting.
Southern Emu-wren (Fleurieu Peninsula), Mount Lofty Southern Emu-wren Stipiturus malachurus intermedius SA Nest up to 1 metre above the ground in grass tussocks.
Vulnerable bird species
Squatter Pigeon (southern) Geophaps scripta scripta Qld, NSW Nest in a scrape in the ground.
Plains-wanderer Pedionomus torquatus SA, Qld, NSW, Vic Ground-nesting species.
Black-breasted Button-quail Turnix melanogaster Qld, NSW Ground birds that live in grasslands (open habitat).
Slender-billed Thornbill (western) Acanthiza iredalei iredalei WA Nest within 1 metre of the ground.
Thick-billed Grasswren (eastern) Amytornis textilis modestus NSW, SA, NT Nest close to the ground.
Thick-billed Grasswren (Gawler Ranges) Amytornis textilis myall SA Nest in shrubs.
Thick-billed Grasswren (western) Amytornis textilis textilis WA Nest in low bushes.
Noisy Scrub-bird Atrichornis clamosus WA Nest in rushes or shrubs close to the ground.
Partridge Pigeon (western) Geophaps smithii blaauwi WA Nest in a scrape in the ground.
Partridge Pigeon (eastern) Geophaps smithii smithii NT Nest in a scrape in the ground.
Malleefowl Leipoa ocellata WA, SA, NSW, Vic This species is a mound-builder and so their eggs and hatching chicks are potentially at risk from fire ant predation
Western Whipbird Psophodes nigrogularis WA, SA, Vic Nests less than 1 metre above the ground, nests are shallow, cup-shaped and low to the ground.
Southern Emu-wren (Eyre Peninsula) Stipiturus malachurus parimeda SA Heath dwelling
Mallee Emu-wren Stipiturus mallee SA, NSW, Vic Spinifex habitat, utilise undergrowth for protection
Unlisted species at risk from fire ants
Quails Subfamily Phasianinae Widely distributed including species in Qld Ground birds in grassland areas with simple nests located under bushes and grass.
Button-Quails Family Turnicidae Widely distributed including species in Qld Ground birds that live in grasslands (open habitat).
Australian Brush-turkey, Orange-footed Scrubfowl Family Megapodiidae Northern Australia and Qld, NSW These species are mound-builders (megapodes) and so their eggs and hatching chicks are potentially at risk from fire ant predation
Bustards Family Otididae Widely distributed including species in Qld Eggs are laid in a ground scrape.
Wetland Birds eg.Grebes (Family Podicipedidae), Herons, Egrets and Bitterns (Family Ardeidae), Geese, Swans and Ducks (Family Anatidae) etc Widely distributed including species in Qld As fire ants have evolved in a flooded habitat and they can float across water in a mat of ants, swamp and wetland habitats are at risk including nests on reed mats.
Waders Families Jacanidae, Burhinidae, Rostratulidae, Haematopodidae, Charadriidae, Recurvirostridae, Scolopacidae, Phalaropodidae, Glareolidae Widely distributed including species in Qld These families have members that nest on the ground or on reed mats, which make their eggs and hatchlings potentially vulnerable to fire ant predation.
Pigeons, Doves Family Columbidae Widely distributed including species in Qld Some pigeons are ground-nesting and some nest on a rock ledge or crevice.
Ground-nesting seabirds eg. Gulls and Terns (Family Laridae) Coastal regions including species in Qld Members of this family have nests on the ground, which makes them potentially vulnerable to fire ants.

Publications used to assess the nomination

  • Allen, C.R., Willey, R.D., Myers, P.E., Horton, P.M. and Buffa, J. (2000) Impact of red imported fire ant infestation on northern bobwhite quail abundance trends in southeastern United States. J. Agric Urban Entomol. 17: 43-51.
  • Department of Primary Industries Fire ant Website including Fire Ant Control Centre updates www.dpi.qld.gov.au/fire ants
  • Eubanks, M.D. (2001) Estimates of the direct and indirect effects of red imported fire ants on biological control in field crops. Biological Control. 21 35-43.
  • Forys, E.A., Quistorff, A and Allen, C.A. (2001) Potential Fire Ant (Hymenoptera: Formicidae) impact on the endangered Schaus Swallowtail (Lepidoptera: Papilionidae). Florida Entomologist 84(2): 254-258.
  • Gotelli, N.J. and Arnett, A.E. (2000) Biogeographic effects of red fire ant invasion. Ecology Letters. 3: 257-261.
  • Jacobi, K. and Wong, L. (1996) Plants face the heat on the way to market. The Nursery Papers, Issue No. 1996#002. http://www.ngia.com.au/np/np_issue2.html
  • Jouvenaz, D.P. (1990) Approaches to Biological Control of Fire Ants in the United States. In Applied Myrmecology: A world perspective. Vander Meer, R.K., Jaffe, K. and Cedeno, A. (eds) Ch 57: 620-627. Westview Press, Oxford.
  • Korzukhin, M.D., Porter, S.D., Thompson, L.C. and Wiley. S. (2001) Modeling temperature-dependent range limits for the fire ant Solenopsis invicta (Hymenoptera: Formicidae) in the United States. Environ. Entomol. 30(4): 645-655.
  • Lofgren, C.S. and Vander meer, R.K. (eds) (1986) Fire ants and leaf-cutting ants: biology and management. Westview Studies in Insect Biology.
  • Majer, J.D. (1999) The Greening of Australia: taking the animals into account LANDCARE REVEGETATION 7. http://envbio.curtin.edu.au/
  • Moloney, S. and Vanderwoude, C. (2002) Potential impacts of Solenopsis invicta (Red imported fire ant) on faunal communities of eastern Australia. Ecological Management and Restoration (in press).
  • Mueller, J.M., Dabbert, C.B., Demarais, S. and Forbes, A.R. (1999) Northern bobwhite chick mortality caused by red imported fire ants. J. Wildlife Management. 63(4): 1291-1298.
  • Natrass R. & Vanderwoude C. (2001) A preliminary investigation of fire ants in Brisbane. Ecological Management & Restoration. 2: 220-223.
  • Stiles, J.H. and Jones, R.H. (2001) Top-down control by the Red Imported Fire Ant (Solenopsis invicta). Am Midl. Nat. 146: 171-185.
  • Solenopsis Invicta www.hear.org/hnis/reports/HNIS-SolInvI01.pdf 
  • Sutherst, R.W. (2001) Red Imported Fire Ant Solenopsis invicta: CLIMEX Species Report. Unpublished report to Qld Dept of Primary Industry: Brisbane
  • Vinson, S. B. (1997) Invasion of the Red Imported Fire Ant (Hymenoptera:Formicidae). Spread, biology and impact. American Entomologist. Spring 1997:23-39.
  • Vogt, J.T., Appel, A.G. and West, M.S. (2000) Flight energetics and dispersal capability of the fire ant Solenopsis invicta, Buren. Journal of Insect Physiology 46: 697-707.
  • Wojcik, D.P., Allen, C.R., Brenner, R.J., Forys, E.A., Jouvenaz, D.P. and Lutz, R.S. (2001) Red Imported Fire Ants: Impact on Biodiversity. American Entomologist. 47(1): 16-23.
  • Zettler, J.A., Spira, T.P. and Allen, C.R. (2001) Ant-seed mutualisms: can red imported fire ants sour the relationship? Biological Conservation 101 249-253.