Background

Implications

Regional aspects

Indicators

Management responses

Discussion

Future directions

Recommendations

Related issues

Background

An animal pest is an introduced animal with an established self-supporting population in the wild (also known as feral or naturalised) that is a threat, for example to human health, primary production and/or the natural environment.

Since the early days of European settlement many animals from interstate and overseas have been introduced, either deliberately or accidentally into Tasmania.

While some of these species have not survived, others have increased rapidly in their numbers to form self-supporting populations in the wild. These populations often have detrimental affects on the natural environment, human health, agricultural production, the horticultural industry and forestry activities. These animals are known as animal pests. Pests, which specifically impact on environmental values, such as on native plants and animals, are termed environmental pests.

Currently 60 introduced vertebrate species have been recorded in Tasmania, of which 32 are recognised as environmental pests. Examples include foxes, rabbits, ferrets, cats, rats and the European carp.

Approximately 952 introduced invertebrate species have been recorded in Tasmania, with 74 recognised as pests. Most of the invertebrate pests impact agriculture production, with only 12 recognised as environmental pests. Examples of the latter include the European wasp, the northern Pacific seastar marine pest and the mainland yabby, which inhabits inland waters.

The number of naturalised pests and environmental pests in Tasmania, 2001.

Caption: Not all naturalised species become pests and not all pests become environmental pests

Naturalised animals	Pests	Environmental pests	Environmental pest list
Vertebrates
60	32 (i.e. 32 of 60)	32 (i.e. 32 of 32)	15 mammals,      12 birds,        5 freshwater fish
Invertebrates
952	74 (i.e. 74 of 952)	12 (i.e. 12 of 74)	2 wasps, 2 bees, 1 yabby, 1 mussel, 1 crab, 1 clam, 1 worm, 1 seastar, 1 oyster, 1 screw shell
Total=1,012	Total=106	Total=44

Implications

• Animal pests have a vast array of environmental and economic impacts depending on the species and the environment in which they live. However the fox represents the single most devastating threat to Tasmania's native mammals and birds. Tasmania is recognised as a national and international fauna haven due to the lack of foxes, but should the species become established, Tasmania's native land animals would all be at risk.
   
• The commercial livestock industry would also be at risk. For example it has been estimated that domestic stock comprises 80% of all food eaten by the estimated 10-30 million foxes, which occur on mainland Australia. In 1998, Tasmania's commercial livestock industry was valued at around $348 million per annum. The economic losses of livestock from fox attacks could equate as a much as $34.5 million per annum in Tasmania's sheep industry alone (wool and slaughter).
   
• No studies are known that give economic impacts of the effects of predation on native mammals to nature based tourism industry.
   

Examples of impacts from animal pests in Tasmania.

Environmental pest	Environmental/economic impacts
Land
Fox	Predation of native mammals and ground nesting birds. Many marsupials are already extinct due to fox predation on mainland Australia. The economic losses of livestock from fox attacks could equate as a much as $34.5 million per annum in Tasmania's sheep industry alone (wool and slaughter).
Feral cat	Prey upon native mammals, birds, reptiles (particularly skinks), frogs, fish and invertebrates. Economic losses of livestock through disease.
Rat	Prey upon native birds, reptiles (e.g. skinks) and invertebrates. They have the potential to introduce disease. They have particularly devastating impacts on smaller sea bird populations (e.g. fairy prions and diving petrels) as they predate on the eggs, babies and adults.
Ferret	Ferrets are very successful predators. They prey on for example ground nesting and burrowing birds and native mammals. They also have the potential to introduce disease.
Rabbit	Over-grazing, changes to vegetation structure, habitat losses to flora and fauna, soil erosion from burrows.
Common starling	Occupy and degrade nesting hollows needed for breeding of native birds, such as the already threatened orange-bellied parrot.
European wasp	Prey upon many native invertebrates with as yet unstudied consequences.
Marine
Northern Pacific seastar	Listed as a noxious fish under the Living Marine Resources Management Act 1995. Feeds on a range of native marine species, primarily shellfish. Can potentially impact directly on the $112 million marine farming industry (e.g. oyster) and the $194 million wild fisheries industry (e.g. scallop) (2000-01 data - Fisheries Statistics, DPIWE).
European shore crab	Listed as a noxious fish under the Living Marine Resources Management Act 1995. Major cause of death in native crab and shellfish populations.
Giant fan worm	Listed as a noxious fish under the Living Marine Resources Management Act 1995. Evidence suggests that dense beds may intercept settling organic material and thus interfere with nutrient cycles.
Inland waters
European carp	The European carp is listed as a controlled fish under the Inland Fisheries Act 1995 and a noxious fish under the Living Marine Resources Management Act 1995. They destroy fragile water plants, increase turbidity, nutrient enrich waterways leading to algal blooms. Do not predate on native fish. However, they predate on invertebrates, thus competing with native fish for food.
Goldfish	Do not predate on native fish. However, they predate on invertebrates, thus competing with native fish for food.
Eastern Gambusia	The eastern Gambusia is listed as a controlled fish under the Inland Fisheries Act 1995. They out compete native fish especially in degraded systems and harass and nip the fins of other small fish.
Mainland yabby	The mainland yabby is listed as a controlled fish under the Inland Fisheries Act 1995. They impact native habitats as they destroy aquatic vegetation, increase turbidity and have the potential to introduce disease. Due to their burrowing nature they also damage farm dams, which may cause leakage problems.

Regional aspects

• The distribution of animal pest species in Tasmania is species dependent. Some species, such as the feral cat, are widespread. Whereas others, such as the feral pig, which is only found on Flinders Island Bass Strait, are restricted in their distribution.
   
• Information on areas that have been protected from pest species, notably some of Tasmania's offshore islands, is also important, as these places need to be managed to preserve their unique position as a haven for native animals. This information may become more significant if refuges are required from an established fox population on mainland Tasmania. Currently, few surveys have been undertaken on the distribution of not only pest species on Tasmania's offshore islands but on the native species that they maybe placing under threat.
   

Indicators

Introduced Species that are Naturalised - at a glance

• Continued in depth

• In total there are 60 naturalised vertebrate (i.e. animals with backbones e.g. feral cats) animal species and 952 naturalised invertebrate (i.e. animals without backbones e.g. wasps) species in Tasmania.
   


• Of the 60 vertebrate species 32 are considered to be environmental pests. Of the 952 invertebrate species 12 are considered to be environmental pests.
   


• Since 1997 three new species recognised as pests have been recorded in Tasmania: foxes (Vulpes vulpes), ferrets (Mustela furo) and eastern Gambusia (Gambusia holbrooki), which is a type of fish. The fox represents the single most devastating threat to Tasmania's native mammals and birds. Tasmania is recognised as a national and international fauna haven due to the lack of foxes, but should the species become established here all of Tasmania's native land animals would be significantly at risk.
   

Animal Pests Declared - at a glance

• Continued in depth

• Sixty naturalised vertebrate species and approximately 952 naturalised invertebrate species have been recorded in Tasmania.
   


• Of the 60 naturalised vertebrate species, 32 are recognised as environmental pests. Examples include fox, cat, goat and the European carp. All Tasmanian vertebrate species are restricted to land, estuarine and inland water environments. No vertebrate pests are known from the marine environment. Of the 32 recognised environmental pests, only two have been formally declared as pests: European carp (Cyprinus carpio) and the eastern Gambusia (Gambusia holbrooki), which is a type of fish.
   


• Of the approximate 952 naturalised invertebrate species, 12 are recognised as environmental pests. Examples include the European wasp, the northern Pacific seastar marine pest and the mainland yabby, which inhabits inland waters. Of these only four have been formally declared a pest: mainland yabby (Cherax destructor); European shore crab/green crab (Carcinus maenas); giant fan worm (Sabella spallanzanii) and the northern Pacific seastar (Asterias amurensis).
   


• Thus in total there are 44 environmental pests in Tasmania of which six have been formally declared by legislation as a pest species.
   

Environmental Pests Covered by Control/Eradication Plans - at a glance

• Continued in depth

• Of the 44 environmental pests that exist in Tasmania only 14 are covered by control/eradication plans (i.e. management plans, management programs and/or strategies). It is also important to note that many of these programs are for individual areas and do not cover the full geographic distribution of the relevant species.
   

On Ground Management Plans for Vertebrate Pest Species - at a glance

• Continued in depth

• Of the 60 naturalised vertebrate species in Tasmania, 32 are recognised as environmental pests. Examples include foxes, rabbits, ferrets and feral goats and cats. Of the 32 environmental pests only three species have active management plans.
   
• These plans however, only cover a small percentage of their existing range. For example, only 0.18% of the feral cat and black rat range is covered by a management plan and only 3% of the rabbit range.
   

Outer Islands with Introduced Vertebrate Pests and The Number of Those Islands with Active Pest Management Actions being Implemented - at a glance

• Continued in depth

• Only three of the 59 islands known to support vertebrate pests have active (i.e. as at February 2002) pest management actions in place. These are Flinders, Bruny and Macquarie islands.
   
• The most common vertebrate pests on the outer islands of Tasmania are rabbits, followed by mice, cats and rats.
   

Management responses

• Vertebrate pest management on Macquarie Island has been conducted since 1974. Also the development of quarantine strategies to prevent further introductions to the island.
   


• Carp eradication program has been ongoing at Lake Crescent and Sorell.
   


• The State Government has formed the fox free Tasmania taskforce to prevent the establishment of foxes in Tasmania. Six field officers and 15 fox eradication casuals have been employed, and are currently undertaking a co-ordinated eradication program in key areas of the State. Field courses have been conducted for farmers and other landholders and a communications strategy is being implemented.
   


• The need for a vertebrate pest eradication strategy (with on-ground eradication program) for Tasmania's offshore islands has been identified and funding options continue to be explored.
   


• A study of the impact of feral pigs on Flinders Island (Underwood 2000) has been undertaken and eradication measures commenced in co-operation with the local community.
   


• A two-year project was commenced in 1999 by the University of Tasmania to examine the impact of feral Pacific oysters on assemblages of native species.
   


• From the 1st July 2001 new ballast water arrangements came into force for all international vessels visiting Australia. Permission must now be granted in writing from a quarantine officer before ballast waters can be discharged in Australian ports or waters. To help the quarantine officers assess which ships are a larger risk, a decision support system has been introduced, available to ships from the world wide web. Alternately, the vessels can discharge their ballast waters at sea or use an on-board treatment system.
   
• A Commonwealth-funded goat eradication program has been carried out in key areas of the State during the past five years and has achieved localised success.
   

Discussion

In 2001 there was a total of 1,012 (60 vertebrates, 952 invertebrates) known naturalised animal species (i.e. introduced species that have established self-supporting population in the wild).

Of the 1,012, 44 (32 vertebrates, 12 invertebrates) are considered to be environmental pests. However, only six of the 44 have been formally declared as pests on either the Living Marine Resources Management Act 1995 and/or the Inland Fisheries Act 1995: European carp (Cyprinus carpio); eastern Gambusia (Gambusia holbrooki); mainland yabby (Cherax destructor); European shore crab/green crab (Carcinus maenas); giant fan worm (Sabella spallanzanii) and the northern Pacific seastar (Asterias amurensis).

Since the last State of the environment report in 1997, three new species recognised as pests have been recorded in Tasmania: foxes (Vulpes vulpes), ferrets (Mustela furo) and eastern Gambusia (Gambusia holbrooki), which is a type of fish.

Animal pests represent one of the most serious threats to Tasmania's biodiversity both on land and in water. However the fox represents the single most devastating threat to Tasmania's native mammals and birds.

For this reason the maintenance of island ecosystems is even more important. The outer islands serve as safe havens for the preservation of species that may otherwise become threatened on mainland Tasmania in the future.

However, 59 of Tasmania's outer islands already have vertebrate pests. Island ecosystems are particularly vulnerable to the affects of naturalised species. On some islands for example introduced pests have caused major declines and extinctions of native species, especially sea birds.

However, only three of the 59 islands in February 2002 had active pest management actions in place: Flinders, Macquarie and Bruny islands.

Of the total 44 environmental pests that exist in Tasmania only 14 are covered by control/eradication plans (i.e. management plans, management programs and/or strategies). Of the 32 environmental vertebrate pests only three species have active on the ground management plans. Many of these programs are for individual areas and do not cover the full geographic range of the relevant species.

Future directions

Management of animal pests will require an ongoing commitment. There is a need for ongoing feral pest eradication on Macquarie Island. Continuing efforts are required to prevent the establishment of foxes in Tasmania. Feral cats should be eradicated from Tasman Island and other islands with important natural values. There is a further requirement to control the expansion of wild trout and to manage the impact of problem bird species in rural areas.

Tasmania Together and the RMPS

Relevant Tasmania Together goals and standards for 'Biodiversity' are listed in the linked file. The Tasmania Together Progress Board reported on progress toward targets for benchmarks set (Tasmania Together Progress Board 2003). Indicators, targets and baseline data are available in the latest Progress Report June 2003. Further information, including progress report updates, is available from Tasmania Together.

Involvement of the community, and the fair and orderly use of resources are also fundamental principles of the RMPS. The RMPS objectives have been developed to advance the principles of sustainable development.

Recommendations

Related issues