State of the Environment Tasmania Home
Chapters Report contents
Biodiversity Index of chapters
Introduced Species Index of Biodiversity issues

Background

Implications

Regional aspects

Indicators

Management responses

Discussion

Future directions

Recommendations

Related issues

Related case studies

Background

Introduced species are foreign species (e.g. roses, blackberries, foxes, wasps, root rot) that have arrived accidentally or have been introduced intentionally. Once introduced species have established self-supporting populations in the wild, they are termed naturalised or feral.

Since Tasmania was colonised by European settlers, hundreds of foreign plants and animals have been introduced into Tasmania. Of these 723 plants and 1,015 animal species are known to have become naturalised. One fungal species and three species belonging to the Kingdom Chromista (e.g. Phytphthora cinnamomi or root rot) have also become naturalised.

Many introduced species such as crop plants, farm animals and game animals are economically beneficial, and others such as pets (that are managed responsibly) and ornamental plants are harmless to the environment.

However, approximately 16% of the naturalised species in Tasmania have become a significant problem to primary production and/or the natural environment and are known as pests. Such pests are usually widespread and can be exceedingly costly to control or eradicate. They can devastate farms and forests, impede waterways, foul lakes and ponds, affect human health, and invade natural areas and deplete or replace native species both on land and in water.

Examples of plant pests (i.e. weeds) in Tasmania include blackberries, gorse, serrated tussock and Japanese kelp. Examples of animal pests include foxes, feral cats, the mainland yabby (which inhabits inland waters) and the northern Pacific seastar. Phytophthora, an introduced blight (similar to a fungus) that attacks the roots of susceptible plants, is also a huge problem. In some native plant communities, epidemic disease can develop, causing the death of a large number of plants.

Implications

  • It is estimated that weeds cost Tasmania $66 million per year (Ministerial Working Group 1996). This includes costs to primary production and to the natural environment.
     
  • The impact of some introduced species into Tasmanian waters has been devastating for marine and freshwater ecosystems but no calculations have been made to determine the cost in dollars. Introduced species compete with native species for habitat space or food, preying on them or generally changing the habitat.
     
  • Marine pests can potentially impact directly on the $112 million marine farming industry (e.g. salmon and oyster) and the $194 million wild fisheries industry (e.g. abalone and rock lobster) (2000-01 data - Fisheries Statistics, DPIWE).
     
  • Many introduced species have significant commercial value but simultaneously can be devastating for both marine and freshwater ecosystems. For example there has been considerable social, political and economic debate centred on Pacific oysters and their value as a commercial and/or recreational fishery, in contrast to the environmental consequences of their introduction. The same can be said for trout and salmon. Similar debates occur in relation to the personal and recreational benefits of pet ownership and their environmental impacts on native fauna. Also, radiata pine is an important economic resource for the State but also becomes an invasive pest in bushland. Blackberries provide a honey resource for apiarists but are also invasive in the high rainfall areas of the state.
     
  • The absence of particular introduced species has also allowed native species in Tasmania to survive. For example, many marsupial species have been decimated on the mainland due to the presence of predatory species such as dingoes and foxes. The relatively long absence of these two species in Tasmania has allowed a much richer diversity of marsupial species (e.g. bettongs, bandicoots, antechinus, eastern quoll, Tasmanian devil) to survive in the State.
     
  • Pests can also severely harm agricultural markets. Pest free status has huge marketing advantages. Tasmania has a relatively insect pest free status, which has enormous economic advantage to the local community. Tasmania's current fruit fly free status represents a competitive advantage for the export of fresh fruit to markets overseas, and pesticide residues in locally grown food are likely to be lower because there are fewer pests on Tasmanian farms.
     

Regional aspects

  • On land, introduced species, while being prevalent in the settled and agricultural areas of the State, are not restricted to these areas. Even the south-west wilderness areas have introduced species such as feral cats, root rot (Phytophthora cinnamomi), bumblebees, European wasps and many weed species such as marram grass.
     
  • In the marine environment naturalised species are concentrated around areas of high vessel traffic such as ports and marinas. These areas are often highly disturbed environments that provide available niches that can be readily colonised by introduced species. These species, which can travel across thousands of kilometres of ocean, are transported on the hulls of recreational, fishing and commercial vessels, and in the ballast water of ships. In Tasmania naturalised species are concentrated in coastal embayments (e.g. Southport, Triabunna) and estuaries such as the Derwent and Tamar.
     
  • In the freshwater environments (e.g. lakes, rivers, farm dams) introduced freshwater fish are present in most lake and river systems in Tasmania. Introductions commenced in the late 1800s when acclimitisation societies successfully transferred several species from Europe for recreational purposes. In more recent times additional species of fish and invertebrates have been introduced illegally to the State as bait for fishing, domestic consumption, or as misguided insect control measures. Several of these species have distributions focused around farm dams surrounding population centres, others have migrated or been intentionally distributed throughout the State. Most of the species introduced to the State have prospered primarily due to the lack of competition from native species and the wide range of niches available. The continued introduction and movement of fish is a significant environmental issue that threatens not only biodiversity but also the sustainability of fisheries in Tasmania.
     

Indicators

Naturalised plants in Tasmania (1800 to 1999).

Introduced Species that are Naturalised - at a glance

  • Seven hundred and sixteen naturalised vascular-plant species are known from Tasmania. Long-term trend data shows that between 1878 and 2000 (122 years) the number of naturalised plant species increased seven times from 104 to 716 species. Of the 716 species 162 are considered to be weeds in Tasmania.
     
  • There are seven naturalised non-vascular plants known from Tasmania, all of which are macroalgae (e.g. large seaweeds such as kelp) found within the marine environment. Of these one (Japanese kelp) is recognised as a pest under the Fisheries (General and Fees) Regulations 1996.
     
  • Sixty naturalised vertebrate animal species are known from Tasmania, most of which are birds (31 species), mammals (17 species) and fish (9 freshwater and 2 saltwater species). Only one introduced reptile species is known from Tasmania. There are no known naturalised frog species. However, there is concern that individual frogs maybe entering the State via fresh food produce. If frogs from mainland Australia are introduced into Tasmania they may carry Chytrid fungus, which is being attributed to frog decline worldwide. If you find a frog in your shopping, do not release it and contact the University of Tasmania, the Tasmanian Museum and Art Gallery in Hobart or the Queen Victoria Museum in Launceston.
     
  • Most of the naturalised invertebrate species in Tasmania belong to the group Arthropoda (67%). Examples include insects, spiders, crabs and centipedes. The other two main groups are Rotifera (25%), which are freshwater microfauna and the Mollusca (3.5%), which include the bivalves, snails, squid and octopus. Although only 1.3% of the introduced invertebrate species are regraded as environmental pests they cause widespread economic and environmental problems.
     
  • Urochordata (e.g. ascidians, sea squirts, salps, tunicates) are non-vertebrate chordates, which live in the marine environment. Up until 2001 three naturalised species of urochordata had been recorded in Tasmanian waters.
     
  • There is only one known naturalised fungal species in Tasmania (Amanita muscaria). However, this number is likely to be significantly underestimated as only between 5-30% of species belonging to the Fungi Kingdom have been described.
     
  • There are three known naturalised species belonging to the Kingdom Chromista. Two species of toxic dinoflagellates, which produce potent toxins and which can threaten marine ecosystems. The other is root rot (Phytophthora cinnamomi), which significantly threatens susceptible plant communities.
     

Quarantine Seizures per Passenger % - at a glance

  • The increase or decrease in the percentage of the number of seizures per passenger from year to year is reflective of the effectiveness of quarantine management and control measures. As this is the first year that the data has been collected in this format it is not possible to determine the percentage increase or decrease of seizures per passenger between 1997 and 2002.
     

Management responses

  • Various pest management programs in Department of Primary Industries Water and Environment, Forestry Tasmania, Inland Fisheries Service and the CSIRO Division of Marine Research are being conducted (see Animal Pests and Plant Pests (Weeds) and Diseases for further details).
     

  • 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. These management responses are discussed in more detail in Marine Pests and Diseases
     

  • An action plan to prevent the introduction of the European red fox into Tasmania and to maintain Tasmania's fox-free status was developed by DPIWE in 2001. The Tasmanian Fox Free Taskforce was established in 2001 and is undertaking a co-ordinated fox eradication program in key areas of the State.
     
  • A national threat abatement strategy for phytophthera cinnamomi is currently being implemented in Tasmania to combat the spread of the disease.
     

Discussion

Introduced species are foreign species (e.g. roses, blackberries, foxes, root rot, wasps) that arrived accidentally or have been introduced intentionally. Once introduced species have established self-supporting populations in the wild, they are termed naturalised or feral. Examples in Tasmania include feral cats and radiata pine.

As at 2001 there were 1,742 known introduced species in Tasmania. Most of these are invertebrates (e.g. wasps) (54.6%), followed by vascular plants (e.g. blackberries) (41%), vertebrates (e.g. cats) (3.4%), non-vascular plants (e.g. mosses, seaweeds) (0.4%) and species belonging to the group Urochordata (e.g. ascidians, sea squirt, salps) (0.17%), Fungi (0.06%) and Chromista (e.g. root rot) (0.17%).

Many introduced species such as crop plants, farm animals and game animals are economically beneficial, and others such as pest (that are managed responsibly) and ornamental plants are harmless to the environment.

However, 16% (271) of the naturalised species in Tasmania have become a significant problem to primary production and/or the natural environment and are known as pests.

Examples of plant pests (i.e. weeds) in Tasmania include blackberries, gorse, serrated tussock and Japanese kelp. Examples of animal pests include foxes, feral cats, the mainland yabby (which inhabits inland waters) and the northern Pacific seastar. Phytophthora, an introduced blight (similar to a fungus) that attacks the roots of susceptible plants, is also a hug problem. In some native plant communities, epidemic disease can develop, causing the death of a large number of plants.

Future directions

The draft Nature Conservation Strategy (!source=583!;) proposed a number of initiatives to combat the incursion and spread of weeds and pests:

  • Significantly increase measures to prevent weeds and pests from entering Tasmania. Measures should include:
     

    • developing stronger quarantine inspection protocols and increasing quarantine staffing levels at all major entry points. This should include wildlife enforcement officers to investigate the illegal transfer of native and non-native species, including those listed under the Convention of International Trade in Endangered Species;
       

    • prohibiting the entry of exotic and native wildlife (plants, animals, micro-organisms) into Tasmania (excluding domestic or stock) unless approved for educational, research, display or commercial purposes;
       

    • undertaking rigorous environmental risk assessments before any new introductions for commercial reasons (biological, exotic and genetically modified organisms);
       

    • note that the above two points relate to the current practice where plants can be imported (in accordance with quarantine procedures) from the mainland unless they are prohibited by weed or seed legislation. This allows free access to all other plants without screening for weediness when we know we are currently at risk of many weeds being legally imported. The Commonwealth and some other States approach this from the other direction. They legislatively control all imports unless they are approved for entry following a weed risk assessment; this creates a permitted list for plant entries. There is scope for legislative change to improve control over plant introductions however direction opportunity is yet to be explored;
       

    • supporting the National Wildlife Health Centre to facilitate collaborative links, formalise networks and coordinate preparedness on disease issues;
       

    • ensuring that veterinary advice is available for relevant nature conservation programs, including advice on species management, translocation, and handling and safety protocols;
       

    • having emergency response plans prepared for high-risk introductions and making sure that plans are current, ready for immediate implementation and have resources identified. This is especially a priority for the prevention of further entry and establishment of the European red fox into Tasmania; and,
       

    • strategic planning to identify sites and avenues of high-risk new introductions (e.g. shipping routes, ballast water) and identifying the measures needed to protect the sites or reduce access.
       
  • Measures to control weeds, pests and diseases in Tasmania should be increased. Measures should include:
     

    • adequately resourcing the Tasmanian Weed Management Strategy to drive state weed programs;
       

    • supporting the rapid response strategy being developed for controlling marine pests;
       

    • implementing other National and State strategies to manage weeds and pests and diseases, particularly those which affect threatened elements;
       

    • supporting the implementation of feral pest (weed and animal) eradication on Tasmania's islands through a State plan which identifies priorities and on-ground eradication program;
       

    • implementing the ANZECC policy on translocation to prevent the inappropriate transfer of species (native and exotic) within the State;
       

    • developing stronger regulations to intercept and quarantine exotic species;
       

    • giving priority to eradicating 'starter populations' (i.e. new outbreaks) before they take hold;
       

    • establishing and maintaining a central database of exotic species and their rates of spread in Tasmania; and,
       

    • increasing stakeholder and community awareness of the seriousness of pests, weeds and diseases and the tools available to identify and eradicate them.
       
  • Adopt recommendations/directions proposed by the fox eradication taskforce.
     

  • Support moves towards uniform State legislative procedures for managing weed movement across Australia.
     

  • Research to identify vectors that could facilitate the spread of marine pests from the initial point of introduction - i.e. hull fouling, aquaculture activities etc.
     

  • Develop policy and education/regulation that aimed at minimising the spread of marine pests.
     

  • Public awareness for marine pests- to familiarise the general public about marine pest issues, i.e how they are spread and to encourage them to report pest.
     

  • Monitoring programs in sensitive or high risk areas (high risk areas as identified by 1.0 i.e. marinas, ports etc, sensitive areas i.e. marine reserves, World Heritage Areas etc.
     

  • Ensure that the State policies and legislation complement the National System for the Prevention and Management of Introduced Marine Pests.
     

  • State structure compliments NIMPIS - National Info Marine Pest Info System i.e. it is the State's responsibility to confirm ID when a member of the public reports a pest, they (i.e. the State) are obligated to update the database and notify CCIMPE (Coordinated Committee for the Intro Marine Pest Emergencies).
     

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

2003

Chapter Title

Recommendation Title

Biodiversity

Weeds, Pests and Diseases

Coastal, estuarine and marine

Managing Marine Pests and Diseases

Related issues

Biodiversity

Plant Pests (Weeds) and Diseases

Animal Pests

Coastal, Estuarine and Marine

Marine Pests and Diseases

Related case studies

Rice Grass Management in Tasmania

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