Section 188(4) of the EPBC Act states:
A threatening process is eligible to be treated as a key threatening process if:
it could cause a native species or an ecological community to become eligible for listing in any category, other than conservation dependent; or
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
it adversely affects 2 or more listed threatened species (other than conservation dependent species) or 2 or more listed threatened ecological communities.
This section provides examples of how the threatening process is impacting on native species and ecological communities2 to address the required criteria under the EPBC Act that make it eligible for listing, as outlined above. It also provides information and examples of invasive novel biota included in this KTP. It is not a comprehensive list of all invasive novel biota in each category. Rather, the examples are representative of each category. It is difficult to provide a precise and comprehensive list of all invasive novel biota in Australia that threaten biodiversity. This KTP is an overarching KTP, which recognises there are many novel biota that currently impact on biodiversity and that there are additional species that may provide a new threat in the future. A. Could the threatening process cause a native species or an ecological community to become eligible for listing as Extinct, Extinct in the Wild, Critically Endangered, Endangered or Vulnerable? There are a number of species not listed as threatened under the EPBC Act that are likely to be negatively impacted by novel biota. However, there are currently insufficient quantitative data available to enable assessment of the impacts on most of these species against this criterion. There is however, evidence that the threatening process could cause Aepyprymnus rufescens (rufous bettong), Ornithoptera richmondia(Richmond birdwing butterfly) and Bidyanus bidyanus (silver perch) to become eligible for listing as threatened under the EPBC Act. These species’ eligibility for listing under the EPBC Act is assessed below using relevant criteria set out in the Environment Protection and Biodiversity Conservation Regulations 2000. The species would be considered to be vulnerable if they met any one of the criteria set out in the regulations.
Aepyprymnus rufescens (rufous bettong) The following criterion is relevant in the case of Aepyprymnus rufescens (rufous bettong): ‘It has undergone, is suspected to have undergone or is likely to undergo in the immediate future, a substantial reduction in numbers’ as a result of competition, predation or herbivory and habitat degradation by the vertebrate pestEuropean or red fox (Vulpes vulpes). The rufous bettong is a small marsupial, 70–80 cm long from nose to tail, weighing about 3250 grams, with reddish-brown fur. They normally move quite slowly by placing the forelegs on the ground and bringing the hindlegs forward together, but can also hop (NSW DECCW, 2005). This species fits into the critical weight range of 35 g to 5500 g for extinctions and declines of non-flying mammals across Australia (Burbridge and Mckenzie, 1989). The rufous bettong inhabits grassy woodlands and forest in areas having tall native grasses and no shrub layer in northern NSW and Queensland (Seebeck and Rose, 1989). Rufous bettongs are generally active from dusk to dawn when they feed on grasses, herbs, seeds, flowers, roots, tubers, fungi and occasionally insects (NSW DECCW, 2005). The rufous bettong was once common down the east cost of Australia but has undergone substantial population declines, particularly in the southern part of its range (Dennis and Johnston, 2008, pp 285–286). It is listed as vulnerable in New South Wales under the Threatened Species Conservation Act1995 and regionally extinct in Victoria under the Flora and Fauna Guarantee Act 1988. The red fox was introduced into Australia for recreational hunting in 1871 and spread rapidly to become one of the widest spread invasive animals in the country (McLeod, 2004). Foxes have significantly contributed to the extinction pressures faced by many Australian species (Mahon, 2009). Foxes pose the most threat to small native mammals and generally prey upon medium-sized to small prey (e.g. possums and small marsupials). In particular, species that fall into the critical weight range are at risk of local extinction when the fox is present (May and Norton, 1996).
The rufous bettong is highly susceptible to fox predation as it is active at the times that most coincide with fox hunting and is prone to surplus killing attacks (May and Norton, 1996; Short et al., 2001). Foxes have been identified as one of the major causes of the regional extinction and declines in ground dwelling mammals including the rufous bettong in Victoria and inland NSW (Dennis and Johnston, 2008, pp 285–286;Mahon, 2009 and references therein). The rufous bettong remains common in areas where fox and rabbit numbers remain low on both sides of the Great Dividing Range in north-eastern New South Wales and Queensland (Dennis and Johnston, 2008, pp 285–286). Fox control is vital in reducing numbers of foxes to help limit the impact on native species, although other predators such as cats have to be considered in any management plan to prevent further mesopredator release that could further endanger species like the rufous bettong (Prugh et al., 2009). If population numbers of foxes were to significantly increase, greater predation of the rufous bettong is likely to occur which would result in the species declining further. Summary of assessment: The Committee considers that the species has undergone a substantial reduction in numbers consistent with a substantial reduction in range. The extent of occurrence of the rufous bettong has declined following the introduction and spread of the red fox particularly in southern Australia. If fox numbers continue to increase and extend in range it is expected that there would be a substantial reduction in the numbers of rufous bettong. The Committee judges that this threatening process could cause the rufous bettong to become eligible for listing under the EPBC Act.
Ornithoptera richmondia (Richmond birdwing butterfly) The following criterion is relevant in the case of Ornithoptera richmondia (Richmond birdwing butterfly): ‘It has undergone, is suspected to have undergone or is likely to undergo in the immediate future, a substantial reduction in numbers’ as a result of competition, habitat loss and degradation caused by the terrestrial weed Dutchman's pipe (Aristolochia elegans).
The Richmond birdwing butterfly is one of Australia's largest butterflies with a wingspan of up to 15 cm and is listed as vulnerable under the Queensland Nature Conservation Act 1992.The species was once reportedly very common in Brisbane and its natural range extended from Maryborough and Gympie in Queensland to Grafton in New South Wales (Gardening Australia, 2003; Vidler, 2004; Sands, 2008). However, habitat clearing and the loss of host plants has resulted in the species now being limited to isolated areas (QLD DERM, 2007). Dutchman's pipe (Aristolochia elegans) is a fast growing vine originating from Brazil, which can reach up to three metres in length and has distinctive flowers that are shaped like a traditional Dutchman's pipe. The Dutchman’s pipe is a prime invader of rainforest habitat and a significant environmental weed that has naturalised in parts of Queensland and northern New South Wales. It is easily cultivated and with its attractive showy flowers has been a widely promoted ornamental plant. Dutchman’s pipe poses a particular threat to the Richmond birdwing butterfly as it is similar in appearance to the native food species. The Richmond birdwing butterfly has two specific host Pararistolochia vines (P. praevenosa and P. laheyana) and only occurs in subtropical rainforest where these vines occur (Sands and Scott, 1998). The introduction of the Dutchman’s pipe into gardens and its subsequent spread into the environment is resulting in a decrease in the Richmond birdwing butterfly (Sands and Scott, 1998). The vine emits a substance that tricks female butterflies into laying their eggs on the vine, but when the larvae hatch they are poisoned as they begin to feed (Sands and Scott, 1998). The increased spread of the Dutchman’s pipe will continue to have a greater impact on the Richmond birdwing butterfly over time as the species is increasingly finding the weed to deposit eggs on rather than the native species, resulting in a higher loss of larvae. Additionally, the female butterflies have been shown to deposit significantly more eggs on Dutchman’s pipe than on native food plants growing nearby (Sands et al., 1997). If the spread of the Dutchman’s pipe continues it is likely that the number of Richmond birdwing butterflies will continue to decrease.
Summary of assessment:The Committee considers that the species has undergone a substantial reduction in numbers consistent with a substantial reduction in range. The species’ distribution is dictated by the distribution of its native food plant and, in future, the latter will be largely dictated by the expansion of various invasive weeds, including the Dutchman’s pipe. The survival of the butterflies that remain is also jeopardised by virtue of the fact that the leaves of the Dutchman’s pipe are poisonous to feeding Richmond birdwing butterfly larvae. Further, the decline in population size and geographic distribution may continue if the threat of invasive weed continues. The Committee considers that the Richmond birdwing butterfly is likely to undergo a substantial reduction in numbers in the immediate future. The Committee judges that this threatening process could cause the Richmond birdwing butterfly to become eligible for listing under the EPBC Act. Bidyanus bidyanus (silver perch) The following criterion is relevant in the case of Bidyanus bidyanus (Silver Perch): ‘It has undergone, is suspected to have undergone or is likely to undergo in the immediate future, a substantial reduction in numbers’ as a result of mortality, habitat loss and degradation caused by the pathogenic Asian fish tapeworm (Bothriocephalus acheilognathi). Silver perch are a medium to large freshwater fish that occur in lowland turbid slow flowing rivers of the Murray-Darling Basin (Lintermans, 2007). The species was once widespread across much of the Murray-Darling basin but has declined across its range; a 93 per cent decline was recorded in the Murray River between 1940 and 1990 (Lintermans, 2007). The species is listed as protected in South Australia and threatened in New South Wales and Victoria. Due to the declining numbers, all populations of silver perch are important for the species’ survival.
The Asian fish tapeworm is associated with cyprinid fish in China and was introduced to Australia with fish, particularly European carp (Cyprinius carpio) (Dove et al., 1997). The prevalence of Asian fish tapeworm throughout Australia is concomitant with the spread of carp and also gambusia (Gambusia holbrooki), which is now spread widely in Australia and has also been recorded as a host of the tapeworm (Dove et al., 1997). The tapeworm causes reduced growth and death of fish, with young fish being particularly susceptible (Dove et al., 1997; Henderson, 2009). The Asian fish tapeworm has been recorded as having a low host specificity allowing it to spread into native fish species and seriously threaten their health (Dove et al., 1997).
The Asian fish tapeworm is a threat to native fish and particularly endangered native fish species (DEWHA, 2000a; Dove and Fletcher, 2000) and is recorded as a threat to the endangered Macquaria australasica (Macquarie perch) a similar species to the silver perch (DEWHA, 2000a; Lintermans, 2007). Infestation with Asian fish tapeworm could result in mortality of juvenile silver perch, causing a further decline of the species.
Summary of assessment: The Committee considers that the species has undergone a substantial reduction in numbers consistent with reduction in range. The distribution has been historically impacted on due to river regulation affecting migration and reproduction behaviour and impacts of invasive fish such as carp. The species could be further impacted on by the spread of the Asian fish tapeworm causing a further decline of species numbers. The Committee judges that this threatening process could cause the silver perch to become eligible for listing under the EPBC Act
Conclusion for Criterion A: The Committee considers that the threatening process is eligible under this criterion as the process could cause the rufous bettong, Richmond birdwing butterfly and silver perch to become eligible for listing as threatened under the EPBC Act. 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? Novel biota, along with other processes, could cause Caretta caretta (loggerhead turtle) and the ecological community ‘Shrublands on southern Swan Coastal Plain ironstones’, both currently listed as endangered, to become eligible for listing as critically endangered under the EPBC Act
Caretta caretta (loggerhead turtle) The loggerhead turtle occurs in the waters of coral and rocky reefs, seagrass beds and muddy bays throughout eastern, northern and western Australia. Nesting is concentrated in southern Queensland and from Shark Bay to the North West Cape in Western Australia, while foraging areas are more widely distributed (DEWHA, 2005c).
Loggerhead turtles are threatened by a range of activities including boat strike, fishing and animal predation. Foxes (Vulpes vulpes) and dogs destroy hundreds of nests in eastern Queensland. The rise in the number of foxes has been consistent with the decline in recruitment of immature loggerhead turtles along the eastern Australian coast. It is thought that there will be reduced recruitment to the nesting adult population between 2000–2020 as a result of fox predation in the 1960s and 1970s (DEWHA, 2005c).
The red imported fire ant (Solenopsis invicta) is a small colonial ant that is native to South America, where its natural distribution appears to be regulated by competition, endemic predators and pathogens. Fire ants are aggressive generalist foragers that occur in high densities, and workers can 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 were discovered at two separate sites in Brisbane, Queensland, in February 2001 and while currently confined to the Brisbane area, the fire ant has the potential to invade much of Australia (DEWHA, 2003).
In the United States of America where fire ants have also invaded and spread, they affect native vertebrate wildlife by consuming soft-shelled eggs, hatchlings, newborn and dependent young and occasionally 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 some birds (DEWHA, 2003).
The impacts of fire ants on fresh and saltwater turtle species in the United States of America, particularly Chelonia mydas (green turtle) and loggerhead turtles have been well documented (Wilmers et al., 1996; Moulis, 1997; Allen et al., 2001). Fire ants have been observed invading turtle nests, feeding on egg,s and stinging, killing and subsequently feeding on hatchlings (Wilmers et al., 1996). In Australia, the loggerhead turtle nesting beaches in Queensland are located less than 400 km north of the current fire ant infestation in Brisbane (DEWHA, 2003; QDPI&F, 2007b). Hatchling success for loggerhead turtle under natural conditions is considered to be low, possibly as low as 10% (Moulis, 1997), so destruction of nests by predators (e.g. foxes and dogs), beach erosion, predation on hatchlings and human activities (Fowler, 1979) all exacerbate the low success rate of turtle hatchings. If the fire ant spreads and invades beaches used by loggerhead turtles as nest sites, this could have a significant impact on turtle numbers resulting in the species being eligible for listing under the EPBC Act in another category representing a higher degree of endangerment.
‘Shrublands on southern Swan Coastal Plain ironstones’ The endangered ecological community ‘Shrublands on southern Swan Coastal Plain ironstones’ is characterised by a very diverse flora, of which many species are endemic, priority species. Endangered flora includes Gastrolobium modestum, G. papilio, Chamelaucium roycei ms (C. sp. C Coast Plain (R.D.Royce 4872)), Dryandra nivea subsp. uliginosa, D. squarrosa subsp. argillacea, Grevillea elongata, G. maccutcheonii and Petrophile latericola ms (P. sp. Whicher Range (G.J.Keighery 11790) WA Herbarium)). The community supports a rich layer of herbaceous annuals under a dense shrub layer. The habitat of seasonally inundated massive ironstone is very rare and mostly cleared, with only 90 hectares remaining (DEWHA, 2000b).
Australia's native vegetation and its dependent biota are threatened by the plant pathogenic fungus Phytophthora cinnamomi that causes the roots of susceptible plants to rot, in many cases killing the plant. It is thought that it was introduced at some time after European settlement. It is now well established in many of Australia’s higher rainfall areas (mean annual rainfall greater than 600 mm) in a mosaic of infected and uninfected areas. Effects range from devastating to inconsequential, depending on environmental factors, which vary both within and between regions. It is estimated there are over 2 000 known plant host species (Shearer et al., 2004)
Depending upon environmental conditions and plant susceptibility, P. cinnamomi can destroy vegetation communities, and several plant taxa are at risk of extinction (Barrett et al., 2008). At least 32 species within the Phytophthora genus occur in various parts of Australia, of which 14 have been recorded in the wild. Only three species (P. cinnamomi, P. cryptogea and P. megasperma) are currently known to cause significant damage in the wild and of these, P. cinnamomi has resulted in the most extensive damage in a variety of habitats (DEWHA, 2009f). Phytophthora die back also poses a threat to many native bird species in south-western Australia, including various parrots and honeyeaters, such as the western spinebill (Acanthorhynchus superciliosus), due to the loss of nectar and seeds (e.g. from various Proteaceae).
Several of the remaining patches of the ‘Shrublands on southern Swan Coastal Plain ironstones’ ecological community are threatened by Phytophthora cinnamomi, with many of the endemic and endangered species of plants in the community being dieback-susceptible. With only a limited area of uncleared habitat remaining, the loss of any remaining part of the community would impact on the survival of the community as a whole and could result in the community being eligible for listing under the EPBC Act in another category representing a higher degree of endangerment.
Conclusion for Criterion B: The Committee considers that the threatening process is eligible under this criterion as the process could cause both the loggerhead turtle and ‘Shrublands on southern Swan Coastal Plain ironstones’ to become eligible for listing as critically endangered, a category which represents a higher degree of endangerment under the EPBC Act. C. Does the threatening process adversely affect two or more listed threatened species (other than conservation dependent species) or two or more listed threatened ecological communities? The majority of listed threatened species and ecological communities are threatened by one or more novel biota. In listing advices novel biota are the greatest threat facing listed species and ecological communities and is a key focus of most recovery plans. The following assessments consider novel biota in each of the six main categories identified in this KTP:
Competition, predation or herbivory and habitat degradation by vertebrate pests.
Competition, predation or herbivory and habitat degradation by invertebrate pests.
Competition, habitat loss and degradation caused by terrestrial weeds.
Competition, habitat loss and degradation caused by aquatic weeds and algae.
Competition, predation or herbivory and habitat degradation by marine pests.
Mortality, habitat loss and degradation caused by pathogens.
For each of the categories, these assessments provide a summary of novel biota present in Australia in that group that pose a threat to native species and ecological communities and an example of how a particular novel biota in that category is adversely affecting listed threatened species and ecological communities.
Competition, predation or herbivory and habitat degradation by vertebrate pests It has been estimated that 73 invasive vertebrate pest animal species have established wild populations in Australia, including mammals, fish, birds, reptiles and amphibians (Bromford, 2003). Intentionally-introduced species include the European rabbit (Oryctolagus cuniculus), red fox (Vulpes vulpes), cane toad, Indian myna (Acridotheres tristis) and starling (Sturnus vulgaris). Other vertebrate species have been brought as domestic pets or stock and escaped, or been released into the wild to establish populations, such as the donkey (Equua asinus), one-humped camel (Camelus dromedarius), feral cat and deer (Axis axis, A.porcinus, Cervus elaphus,C.timorensis, C. unicolour and Dama dama). Further species such as the house mouse (Mus musculus), the black or ship rat (Rattus rattus) and brown rat (R. norvegicus), arrived in Australia incidentally on ships and in imported items (Norris et al., 2005).
Seven of the invasive vertebrates in Australia are among 100 species nominated by the International Union for Conservation of Nature (IUCN) as the world’s most invasive species (Lowe et al., 2000). These include the domestic cat (Felis catus), goat (Capra hircus), house mouse (Mus musculus), pig (Sus scrofa), rabbit (Oryctolagus cuniculus), red fox (Vulpes vulpes), and ship rat (Rattus rattus), the Indian myna (Acridotheres tristis), red-vented bulbul (Pycnonotus cafer), starling (Sturnus vulgaris) and the red-eared slider turtle (Trachemys scripta).
Forty-three non-native freshwater fish species have been recorded in the wild in Australia, of which 34 are reported to have established populations (Koehn and McKenzie, 2004; Lintermans, 2004). One additional species, rosy barb (Puntius conchonius) is now known to be established in northern and Western Australia (Corfield et al., 2008). Five of these freshwater species established in Australia were nominated by the IUCN as among 100 of the world’s most invasive species (Lowe et al., 2000), including carp (Cyprinus carpio), Mozambique tilapia (Oreochromis mossambicus), gambusia (Gambusia holbrooki),rainbow trout (Oncorhynchus mykiss)and brown trout (Salmo trutta).
Seven vertebrate species are listed as KTPs under the EPBC Act (DEWHA, 2009a). These include rabbits, pigs, unmanaged goats, foxes, rats on Australian offshore Islands, cane toads and cats.
Invasive vertebrate pests impact on native species in many ways. Escaped or released domestic animals such as donkeys, camels, buffalo, pigs and horses damage the environment by grazing native plants, fouling water sources, severely damaging the aquatic ecosystems and riparian zones of waterways, causing soil erosion on river banks by destroying vegetation, out-competing native species for food and shelter and acting as vectors for disease (Wittenberg and Cock, 2001, pp 4–5). Similarly, other novel biota such as cats, foxes and introduced fish prey on native species, are vectors for disease and compete for food and shelter. Other species including rats, mice and rabbits, invade the burrows of native species, out-compete them by having high reproduction rate, compete for food and are vectors for disease (Wittenberg and Cock, 2001, pp 4–5).
A number of listed threatened fish species are directly threatened by introduced species. Melanotaenia eachamensis (Lake Eacham rainbowfish) were eliminated from Lake Eacham as a result of translocations of native species (Barlow et al., 1987). The endangered Galaxias fuscus (barred galaxias) is threatened by alien salmonids (Raadik et al., 1996). Almost all of the Tasmanian galaxiids listed under the EPBC Act including the endangered Galaxias auratus (golden galaxias), Galaxias johnstoni (Clarence galaxias) and the vulnerable Galaxias parvus (swamp galaxias) are threatened by trout (and some by redfin perch (Perca fluviatilis)) (TSS, 2006). Gambusiaand redfin have been implicated in the decline of the endangered Nannoperca oxleyana (Oxleyan pygmy perch) and Nannoperca obscura (Yarra pygmy perch) (Arthington, 1996; Hammer et al., 2007, p 206).
For this group of novel biota that impact on biodiversity, the European rabbit (Oryctolagus cuniculus) is provided as one example that further demonstrates the impact of vertebrate pests.
European rabbit (Oryctolagus cuniculus) The European rabbit was introduced into Australia as domesticated individuals with the first fleet, which were released onto a property in Geelong in 1859 by a member of the Victorian Acclimatisation Society for Christmas hunting sport (McLeod, 2004). The rate of spread of the rabbit is recorded as the fastest of any colonising animal anywhere in the world. The speed of spread was aided by the fact that rabbits used the burrows of native species and were favoured by changes to the natural environment made by agricultural practices (McLeod, 2004).
Rabbits are now one of the widest spread mammals in Australia and are found everywhere south of the tropics. The impact of rabbits on the Australian environment has been disastrous and they have significantly altered the botanical composition of extensive areas of natural habitat (Eldridge, 2000; Croft et al., 2002). Rabbits graze heavily on native plant species, killing some and preventing germination and seeding establishment of others. Rabbits transform the landscape and cause soil erosion due to the loss of vegetation (Lange and Graham, 1983; Cooke, 1987; Norris et al., 2005). This grazing reduces the amount of protective vegetation for native species. Rabbits also take over burrows and compete for food (Rolls, 1969, p 67). The presence of rabbits also attracts predatory species, such as cats and foxes that also prey on native animal species (Norris et al., 2005).
This impact can be demonstrated for Macrotis lagotis (the greater bilby), a medium size member of the marsupial family. At the time of European settlement greater bilbies were widespread throughout arid and semi-arid areas of Australia. The species is now currently restricted to small pockets in far western Queensland (Hume et al., 2004). The greater bilby relies on a constant source of invertebrates such as termites, native seeds and roots (Navnith, 2009). After the invasion of rabbits its habitat and food sources were severely restricted, as the food was being overgrazed and the vegetation destroyed. Additionally, the loss of habitat is making the greater bilby more vulnerable to attacks from feral cats and foxes (Hume et al., 2004). When reintroduced into areas where rabbits, foxes and cats have been removed, greater bilbies successfully recolonise the area and breed (Mosby and O’Donnell, 2003).
Rabbits have been listed as a KTP under the EPBC Act (DEWHA, 2009a). Table 1 shows species listed as nationally threatened under the EPBC Act that have rabbits listed as a threat to their ongoing survival.
Table 1: EPBC Act listed species and ecological communities that list rabbits as a threat.
Acanthiza iredalei iredalei
slender-billed thornbill (western)
Amytornis barbatus barbatus
grey grasswren (bulloo)
Amytornis textilis modestus
thick-billed grasswren (eastern)
Amytornis textilis myall
thick-billed grasswren (Gawler ranges)
Cacatua pastinator pastinator
Muir’s corella (southern), western long-billed corella (southern)
Calyptorhynchus lathami halmaturinus
glossy black-cockatoo (south Australian), glossy black-cockatoo (kangaroo island)