Invertebrates in Australia

Invasive species in Australia

Invasive species are a serious threat to the native biodiversity of Australia and are an ongoing cost to Australian agriculture.

The management of weeds costs AUD $3.5 billion yearly.

Management and the prevention of the introduction of new invasive species are key environmental and agricultural policy issues for the Australian federal and state governments.

Invasive species

Diseases, fungi and parasites

Invasive diseases, fungi and parasites in Australia affect many native plants and animals and agricultural crops. Recently Citrus canker was introduced into Australia, and many Queensland citrus orchards have been burned to remove the disease. The fungus Phytophthora cinnamomi, commonly known as Dieback, has created a massive problem in some types of native vegetation - especially Jarrah forest and Banksia woodland.

Feral animals (introduced species)

Australia is host to 56 introduced invasive vertebrate animal species. They can be categorised in the following ways:

  • Invasive - species has a tendency to spread their range into new areas or plague their range
  • Ferals - defined as animals for domestic purposes (ie. pets, recreational use - such as hunting - or Beasts of Burden) which have gone wild.
  • Pests - animals which have a direct effect on human standard of living or the environment/ecosystems in areas where they are present, have a high rate of reproduction and are difficult to control

Feral animals causing most public concern and economic and ecological damage include:

Image Name Species Overview Introduced Reason Introduced from Distribution Feral Pest Threat Level Est Pop Main Control Measures Notes/ Ref
Cane toad Bufo marinus 1935 Biological Control (Cane beetle) South America via Hawaii Queensland (extensive), northern New South Wales, Top End, Kimberley No Yes High 200 million + Culling; Trapping; Genetic (under research) (prolific breeders and bufotoxin kills native animals)
Red Fox Vulpes vulpes 1855 Recreational hunting Europe most of Australia, possibly small population in Tasmania Yes Yes Extreme 7.2 million + 1080 baiting; hunting Elusive prolific predator of native animals and livestock.
European Rabbit Oryctolagus cuniculus Rabbits in Australia 1788 Recreational hunting Europe Throughout Australia (extensive) Yes Yes High 200 million + rabbit-proof fence; Myxomatosis; Calicivirus (RHD) Prolific breeders that destroy land.
Dromedary Camel Camelus dromedarius Australian feral camel 1840 Beast of Burden India Central Australia (extensive) Yes Yes Low 500,000 + Helicopter Culling Grazer, though arid Australian conditions suit the camel perfectly.

Feral animals have very few predators in Australia.

See also: Rabbits in Australia, Australian feral camel

Control

Various programs exist to control invasive species in Australia. A cane toad control program aims at preventing the spread of the species towards Darwin and Western Australia, and involves trapping. Foxes are often baited, although the use of 1080 (sodium fluoroacetate) is also known to affect native animals such as the Quoll and Tasmanian Devil, though the most common and effective method is shooting. 1080 is ideal in the South-West of Australia because a native plant contains the same toxin - therefore most native animals have developed immunity to it. Other species are either open to hunting as a sport (such as the deer) or subject to government sponsored culling programs. Camels and buffalo are often shot from helicopters.
Bounties
Several bounty programs have assisted in the eradication of larger sized pests in Australia.

Ironically, many early bounties were paid for the extermination of native species that were considered a pest to farmers. The Tasmanian tiger or thylacine was one such program that caused extinction, whilst the Tasmanian Devil, Spotted Quoll and Tasmanian Wedge-tailed Eagle all became seriously threatened by bounties.

At various times, bounties have been in place for invasive species such as the wild dog, dingo and fox. In 2002, a Victorian Fox Bounty Trial began fox bounties which have been in place intermittently since 1893 (only 30 years after introduction). Feral cat bounties in Queensland have also been considered to counter the growing problem. The dingo is subject to various controversial bounty systems in Australia. The Australian wolf sub-species was itself introduced before European settlement, however has been considered native of the mainland and is considered a pest to livestock.

Currently, in the Northern Territory (especially around Darwin) a bounty on cane toads exists. When a live, unharmed toad is taken into certain hotels around the Darwin area a pint of Coopers is offered. Afterwards the RSPCA will humanely dispose of the toads.

Invasive birds

Introduced birds considered pests include the Indian Mynah, the Common Starling and Rock Pigeon (common pigeon).

Initially introduced to control locust plagues, the Indian Mynah breeds prolifically in urban environments in the eastern states. The mynah poses a serious threat (such that it has been listed in the World Conservation Union's world's 100 worst invasive species). The bird has caused human health concerns due to the spread of mites and disease and it has also been known to force native birds and their eggs from their nests.

The Rock Pigeon in particular has acidic faeces and can create a mess which damages human property including historic stone buildings.

Control

There are currently no major controls in place for invasive birds in Australia. Programs promoting indigenous plantations to attract native birds are generally not helping the situation.

Starlings and sparrows are currently closely monitored in south-eastern Western Australia.

Despite the number of Rock Pigeons, many people continue to feed the birds bread crumbs and assist them to breed in great numbers. It is not yet illegal to feed pigeons in Australia, and many local proposals to cull pigeons have been rejected.

Invasive freshwater fish species

See also: List of introduced fish in Australia Invasive freshwater fish species in Australia include carp, brown trout, rainbow trout, redfin perch, mosquitofish (Gambusia spp), weather loach and spotted tilapia to name a few. Some introduced freshwater fish species have had devastating impact on Australia's endemic freshwater fish species and other native aquatic life. For example in much of south eastern Australia's freshwater systems introduced carp (often incorrectly called "European" carp) dominate the lowland reaches, while introduced trout species almost completely dominate the upland reaches. While the damaging impact of carp is well recognised, little in the way of control measures have been employed to control their spread. Their ability to colonise almost any body of water, even those previously considered to be beyond their physical tolerances, is now well established.

Insects and other invertebrates

Problem insects include red imported fire ant (Solenopsis invicta), yellow crazy ant (Anoplolepis gracilipes), Western honey bees (Apis mellifera) and European wasps (Vespula germanica; known elswhere by the common name "German wasps"). The elm leaf beetle (Pyrrhalta luteola), discovered in Victoria in 1989 devastates exotic elm trees, themselves imported, and a parasite wasp species as well as the beetle's natural enemy the parasitic fly (Erynniopsis antennata) were in turn introduced in 2001 in an effort to control the pest.

Control

Both the honey bee and European wasp are well established and now impossible to eradicate in Australia. Honey bees take over potential nesting hollows for native animals and are very hard to remove once established.

The fire ant in particular, with its poisonous stings, poses a direct threat to human lifestyle. Although control is extremely difficult and spread quickly, the species is currently effectively quarantined to South East Queensland

The Yellow Crazy Ant is currently quarantined to Christmas Island where it has had a significant environmental impact

Introduced marine pests

A number of marine pests have arrived in Australia in the ballast water of cargo ships. Marine pests include the black-striped mussel (Mytilopsis sallei), the Asian mussel, the New Zealand green-lipped mussel, and the European shore crab. The Northern Pacific seastar in Tasmania, Inverloch and Port Phillip has caused much localised environmental damage. The crown-of-thorns starfish has devastated many areas of the famous Great Barrier Reef.

Weeds

Weeds invade natural landscapes, waterways and agricultural land. A list of Weeds of National Significance (WONS) was created in 1999. It includes the species in the following table.
Common Name Scientific Name Extent in Australia Image
Alligator Weed Alternanthera philoxeroides WA, NT, QLD, NSW, VIC, SA, TAS
Athel Pine Tamarix aphylla WA, NT, QLD, NSW, VIC, SA
Bitou bush / Boneseed Chrysanthemoides monilifera WA, QLD, NSW, VIC, SA, TAS
Blackberry Rubus fruticosus agg. WA, QLD, NSW, VIC, SA, TAS, ACT
Bridal Creeper Asparagus asparagoides WA, NSW, VIC, SA, TAS
Cabomba Cabomba caroliniana NT, QLD, NSW, VIC
Chilean Needle Grass Nassella neesiana NSW, VIC, SA, ACT
Common Gorse Ulex europaeus WA, QLD, NSW, VIC, SA, TAS, ACT
Hymenachne Hymenachne amplexicaulis NT, QLD, SA
Lantana Lantana camara WA, NT, QLD, NSW
Mesquite Prosopis spp. WA, NT, QLD, NSW, VIC, SA
Mimosa Mimosa pigra NT
Parkinsonia Parkinsonia aculeata WA, NT, QLD
Parthenium weed Parthenium hysterophorus QLD, NSW, VIC
Pond-apple Annona glabra NT, QLD, NSW
Prickly Acacia Acacia nilotica ssp. indica QLD, NSW
Rubber Vine Cryptostegia grandiflora WA, QLD
Giant salvinia Salvinia molesta WA, NT, QLD, NSW, SA
Serrated Tussock Nassella trichotoma NSW, VIC, TAS, ACT
Willows Salix spp. except S. babylonica, S. X calodendron and S. X reichardtiji NSW, VIC, ACT

There are many other noxious weeds through Australia including:

Weed management costs the Australian economy AUD$4 billion yearly, weeds are also an environmental problem, they are the second greatest threat to biodiversity after land clearing. Almost half of Australia's 220 declared noxious weeds (under legislation) were introduced deliberately, one third of these as garden ornamentals.

Management of invasive species

The management of invasive species is carried out by individuals, conservation groups and government agencies.

The Australian Quarantine and Inspection Service is responsible for ensuring that no new species with the potential to become invasive species enter Australia. To raise public awareness, Australian Quarantine has featured Australian celebrity nature lover Steve Irwin on a series of television commercials, with the message Quarantine - Don't mess with it..

Several scientific bodies are involved in research for the control of invasive species. The CSIRO has released of several successful biological control agents and developed chemical agents for pest and weed control. For example, the CSIRO released myxoma virus to control wild rabbits in Australia.. Rabbit hemorrhagic disease escaped containment from an Australian Government research facility and spread across Australia. Rabbit hemorrhagic disease was subsequently legalised for the control of wild rabbits. The moth Cactoblastis cactorum was introduced for the control of prickly pear, and the salvinia weevil Cyrtobagous salviniae for the control of aquatic weed Salvinia. More doubtful biological controls were the cane toad, which was introduced to control the sugar cane destroying cane beetle; instead the cane toad ate anything and everything else—the beetle was not its preferred food source given choice. The cane toad in Australia has become the biological control that is most infamous for having been a complete failure as well as becoming an environmental nightmare. It has also led to much public concern and caution when considering the introduction of new biological controls.

Another example of a poorly researched introduced biological control is the sap sucking lantana bug (Aconophora compressa) also from South America that was introduced into Australia in the 1995 to eat the lantana. Unfortunately, the lantana bug also attacks other trees including fiddlewood trees which has caused distress to some gardeners. The lantana bug had been tested for six years on 62 different plants. Aconophora compressa was the 28th insect introduced to control lantana in about 80 years.

Cooperative Research Centres for weed management and pest animal control, have been established by the federal government. They coordinate research and funding between a number of university and government labs for research into control of invasive species.

World Trade Organisation and Australia's quarantine regulations

The World Trade Organisation specified quarantine regulations are weaker than Australia's fairly stringent regulations controlling the importing of raw produce. Following Australia's membership of the WTO, many forms of raw produce once banned have commenced import, with potentially adverse affects and controversy; for example, regarding proposals to import apples from New Zealand or bananas from the Philippines

The weakening of restrictions on importing raw produce into Australia mandated by the World Trade Organisation Future poses risks of introducing exotic disease organisms Case examples include, Chytrid fungus that is threatening numerous Australian frog species with extinction , and mass pilchards deaths in the Southern Ocean from 1995 onwards that are suspected to have been caused by a virus that may have been brought in with imported pilchards .

References

  • The Cooperative Research Centre for Australian Weed Management
  • CSIRO marine pest fact sheets
  • The Department of Environment and Heritage, Invasive Species
  • Weeds of National Significance
  • The Cooperative Research Centre for Pest Animal Control
  • feral.org.au
  • Rabbit Information Service

See also

External links

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