Country reports

Forest invasive species strategies in Australia

Michael Cole
Office of the Chief Plant Protection Officer (OCCPO), Australian Government Department of Agriculture, Forestry and Fisheries (DAFF)

Background

Importance of invasive species issues in Australia

Australia is relatively free from many serious pests of agriculture, including plantation forestry, through its geographical isolation. This position is attributed to the fact that virtually all cultivated crops, many pasture species, and a large proportion of Australia’s plantation forest industries, are based on exotic germplasm. Through rigorous quarantine action, and some good fortune, many serious agricultural pests have been excluded and few indigenous pests have adapted to attack the exotic germplasm - a fact that can be attributed, in part at least, to Australia’s unique flora.

The annual turnover of the Australian forest industry is valued at A$15 billion (US$10.4 billion). Protecting it is becoming increasingly hard due to increases in global trade and travel. The risks of entry and potential establishment of exotic pests has increased the risk and threat of impacts of these pests.

In addition to the natural pathway, through northern Australia from Indonesia and Papua New Guinea, potential pest pathways to Australia include thousands of incoming air and sea freight containers and their contents, 180 million mail items and over 9 million inbound passengers annually. Although numbers tend to vary from year to year, Australia must annually respond to approximately 40 newly recorded plant pests, 200 barrier breaches (pests that have been detected beyond the quarantine barrier but have not yet established) and 15 000 pest interceptions at the quarantine barrier.

Preventing pest introductions is a major component in any invasive species strategy; however, it is not without risk, with increasing pressure from both regulated trade and non-regulated trade (deliberate contravention of quarantine laws). Australia spends A$166 million (US$115 million) on quarantine activities annually and has spent over A$200 million (US$139 million) since 1996 on various plant pest eradication programmes.

In many instances, the impacts of new pests on Australian ecological and agricultural systems are little known. This uncertainty is compounded by the diverse ecological niches that Australia offers - as points of incursion establishment - in both temperate and tropical environments.

Australia’s relative freedom from many plant pests of exotic trees, and the lack of information on the potential impact of exotic plant pests on native plant species, intensifies the importance of appropriate strategies for invasive species. Responding to invasive species also highlights the requirements for, and gaps in, basic plant health capacity issues such as surveillance and diagnostics.

Asian gypsy moth (Lymantria dispar) has been identified as a potential key threat, and has since been confirmed, through additional research on host testing with Australian native species. Although the pest has not evolved with Eucalyptus species, it readily feeds on many, highlighting its potentially significant impact on both commercial and conservation forests. Australia conducts a pheromone-trapping programme in all temperate first ports-of-call - one step to help mitigate this risk.

The aphid Essigella californica was first found in Australia in 1998. National surveys quickly found it in all states despite forest surveillance programmes. The aphid is not known to be a major pest on Pinus radiata elsewhere, or in its native range, but in Australia there are indications that it is causing significant damage in some states and research is continuing. This also highlights the difficulty in identifying key target pests and being able to adequately detect them early enough for effective response.

In 1998, a Bursaphelenchus sp. nematode, similar in taxonomy to B. hunanensis, was detected on various pine species in Melbourne. The dying pines were initially reported by local government workers. As a precaution, a national response was developed that included a survey, and eradication of infected pines in Melbourne. Infected pines showed a syndrome of sudden decline and death, but the syndrome was not consistent and was compounded by other disease and abiotic factors such as salt levels. Pathogenicity testing and diagnostics have proven difficult and to date no confirmation of the species, or illustration of it being a pest, has been made. During national surveys, many previously undescribed nematodes were found (not causing primary disease). This case highlights the lack of understanding of current plant health status, the role of exotics in a new ecosystem and lack of plant health capacity to diagnose potential plant pests, especially those that may not be major pests elsewhere.

Table 1: Forest types of Australia

Source: National Forest Inventory, 2003 (1) National Plantation Inventory, March 2002. Note: (1) column or row totals may not add up due to rounding; (2) the plantation total includes 1 400 hectares of unknown species.

The greatest proportions of the plantation estate are relatively evenly distributed across the three states of New South Wales (NSW), Western Australia (WA) and Victoria (VIC). The most extensive hardwood plantation areas occur in WA, Tasmania (TAS), and VIC, while the most extensive areas of softwood plantations are in NSW, VIC and Queensland (QLD) (Table 1).

Australian hardwood plantations are dominated by Eucalyptus species, supplemented by a small proportion of tropical rain forest and other hardwood species. Of the total hardwood species, Eucalyptus globulus comprises 62 percent (311 340 hectares) and other eucalypts comprise 19 percent (95 360 hectares). Softwood plantations are predominantly Pinus radiata, totalling 716 540 hectares (74 percent of total area of softwood species). Other softwoods including the native Araucaria cunninghamii and exotic P. caribaea and P. elliottii are significant in QLD, while WA has a significant P. pinaster resource.

Key forest pests in Australia

Vertebrate pests

Animal pests are responsible for a suite of destructive impacts including: browsing and ringbarking of mature and juvenile vegetation, competition for food and habitat, erosion, and predation of native fauna. For a comprehensive breakdown of pests, processes or agents impacting on forested areas please refer to Appendix 1.

Foxes are the most widespread exotic animals adversely affecting forested ecosystems. Occurring across mainland Australia, they have severely affected populations of small ground-dwelling mammals. Extensive (and expensive) baiting control programmes have reduced fox populations, but eradication is not foreseen.

Cats are a widespread problem across Australia, particularly in NSW native forests. The NSW National Parks and Wildlife Service estimated in 1997 that there were 400 000 feral cats in NSW alone, and around 12 million feral cats across Australia. These predators have a significant impact on native fauna. Baiting, trapping and shooting are used to manage these pests.

Rabbits are a major agricultural and environmental pest across most of Australia, costing between A$600 million (US$417 million) and A$1 billion (US$695 million) annually. Competing with native animals for food and habitat, they have contributed to the reduced numbers of many native animals. Rabbits destroy the landscape and are a major cause of soil erosion through the prevention of regeneration of native vegetation, foraging on foliage and ring-barking trees. A concentrated and integrated management programme exists for rabbits and includes biological (myxomatosis, calicivirus), chemical (baiting and fumigation) and mechanical control methods (shooting, fencing, warren destruction). In South Australia (SA), the numbers of rabbits are generally low - due to rabbit calicivirus disease (RCD) and other control programmes - however, even at low numbers, their impacts remain severe. Although the overall number of hares in SA is less than that of rabbits, their impact is equally severe in forested areas.

Kangaroos have a widespread and moderate impact in most states. Wallabies account for approximately 80 percent of browsing damage on regenerated juvenile trees following forest harvesting in VIC (1994-1996). In TAS, bark-stripping of young trees by wallabies is prevalent in 10-20 percent of 3-5 year-old Pinus radiata plantations, but mortality resulting from ring-barking (girdling) is rare. Possums also cause significant, localized damage by ring-barking upper stems and causing top death in older trees of Pinus radiata plantations.

Pigs have a severe and widespread impact on agricultural and native ecosystems across Australia, particularly in the Australian Capital Territory (ACT) and QLD. Rooting of soil causes physical damage and erosion, soil fauna is affected and some pathogens can be transmitted (for example, the fungal pathogen Phytophthora cinnamomi). Ground cover is destroyed, the composition of plant communities can change, and invasion by weeds often ensues.

Invertebrate pests

Eucalypt forests, woodlands and plantations are regularly browsed by a wide range of native insects including; leaf-chewing chrysomelid beetles, scarab beetles, sawflies, leaf skeletonizer moth larvae, and sap-sucking psyllids. Infestations are sometimes severe and repeated. Control programmes have been conducted in plantations where attacks may result in reduced growth and damaged form. Except for chronic attacks, eucalypts are generally resilient and able to replace their foliage after infestation subsides.

Where control of severe insect infestations in young plantations is required, insecticides are sometimes used. One of the problems with this approach is that the insecticide can also harm beneficial insects - i.e., those that reduce the population of the pest through predation or parasitism.

The gumleaf skeletonizer (Uraba lugens) causes very widespread and severe defoliation of entire natural eucalypt stands in all states, across a range of climatic and vegetation types, but generally few trees are killed. In plantations, impacts are not usually severe and controls not necessary. In WA this pest has been selected as a target species in the newly implemented FORESTCHECK monitoring programme, together with jarrah leaf miner (Perthida glyphopa) and bullseye borer (Phoracantha acanthocera).

Stick insect (phasmatid) outbreaks, for example Didymuria violescens, occur cyclically in mature eucalypt forests in high elevation regions in NSW and VIC, where entire patches or hillsides of mature eucalypts (e.g. E. viminalis, E. delegatensis, E. regnans) are sometimes totally defoliated. Population monitoring and outbreak predictions are made by monitoring egg numbers in soil and litter.

Christmas beetle infestations occur at the forest/cleared land interface, particularly in red gum communities in VIC, but also in blue gum and flooded gum plantations in eastern Australia. These pests are difficult to control, so breeding strategies are being developed to produce resistant strains of eucalypt. Prolonged chronic outbreaks of sap-sucking psyllids, (for example in red gum forests and woodlands in VIC), which often involve Cardiaspina spp., can result in tree dieback and death.

Wingless grasshoppers cause total defoliation in young eucalypt plantations, particularly during droughts, and have been significant in several states including WA and SA. Pest management programmes are sometimes necessary.

Pests of exotic pine plantations that can reduce the commercial productivity of these forests include the pine-killing woodwasp (Sirex noctilio), Monterey pine aphid (Essigella californica), and the five-spined bark beetle (Ips grandicollis).

Sirex generally attacks stressed pine trees. Wasp numbers sufficiently high to cause significant attack do not generally develop in vigorous healthy stands, but this has been known to happen. In SA and VIC between 1987 and 1989, the Sirex wasp killed more than 5 million P. radiata trees (with a combined value of $10-12 million). The National Sirex Control Strategy programme facilitates an integrated pest management approach based on ensuring low Sirex wasp populations, through the maintenance and release of virulent strains of the introduced nematode Beddingia siricidicola, as well as a range of parasitoid wasps, as biological controls. The programme also encourages optimum plantation thinning practices and site selection to minimize the occurrence of stressed trees in high-risk areas. Regular trapping and surveillance programmes monitor Sirex levels. Controls are implemented to avoid major outbreaks.

The Monterey pine aphid - first observed in Australia in 1998 - is able to infest a range of pine species and has since been detected in most pine-growing areas in all states. Thus far, mild to severe defoliations have been recognized in Pinus radiata plantations in VIC, NSW and SA, but the effects on growth yield are still to be assessed. Aphid levels are being regularly monitored in most states using standard foliage beating methods during surveys.

Ips grandicollis is a serious pine bark beetle pest accidentally introduced from the northern hemisphere and is able to infest all plantation pine species grown in Australia. The beetle has been present in Australia for at least sixty years and occurs in all mainland states and the ACT, but is absent from TAS. Pheromone traps are used to monitor beetle presence and beetle numbers in some states. Population levels build up primarily on fresh logging debris or in damaged or severely stressed standing trees. The beetle is also able to vector blue stain fungi such as Ophiostoma ips. A range of parasitoids has been introduced into Australia to limit beetle numbers.

Weeds

Blackberries (Rubus fruticosus sp. agg.), gorse (Ulex europaeus), Lantana (Lantana camara) and pampas grass (Cortaderia spp.) are examples of exotic plants that have become naturalized pests in Australia. These species compete with native flora in forests and woodlands, and can reduce biodiversity and other values. These four species are included in the Weeds of National Significance programme under the National Weeds Strategy. Pest plants also interfere with crop trees in commercial forest plantations, with associated negative effects on human access, tree establishment and growth, and product yield.

Blackberries occur in all jurisdictions, except the Northern Territory (NT). They are the single most widespread pest plant threat across southern Australia, mainly in regions with annual rainfall more than 750 mm. Current costs and changes in area affected are difficult to calculate. Estimates approximate to 9 million hectares, including non-forested landscapes. Control of blackberry in forests is primarily by spraying with herbicides. Strains of a blackberry rust fungus (Phragmidium violaceum), introduced into Australia during the past 20 years, have had variable but limited success as biological controls. An enhanced major long-term strategy for blackberry management and eradication on a statewide basis has recently been implemented in VIC.

Gorse is more problematic as a weed in TAS and southern VIC than elsewhere in Australia. In TAS alone, the estimated annual cost of production loss in 2001 was A$1 million (US$694 894) and the cost of control and rehabilitation was A$700-1 500 (US$486-1 042) per hectare. Under the National Weeds Programme A$750 000 (US$521 122) was applied to the Tasmanian Gorse Strategy in 2002.

Lantana infests approximately 4 million hectares, predominantly in the coastal forests and woodlands extending from far north QLD to southern NSW, but also occurs to a small extent in parts of the NT, WA and VIC. Whole ecosystems and many species are affected, while others are threatened, by this shade-tolerant, invasive plant, which develops dense shrubby thickets that out-compete native species. Environmental impacts also include major reductions in invertebrate and avian biodiversity. This, in turn, may increase the severity of crown defoliation diebacks in forest or woodland overstoreys. Lantana is gradually extending further inland. Integrated control measures include introduced sap-sucking insects and fungal leaf rust. Cutting back the plant, however, results in stimulated shoot proliferation.

Pampas grasses occur as weeds in VIC, TAS, NSW, SA and WA. National and/or regional weed strategies are in place. In TAS, a state-wide eradication programme, implemented in 1998, successfully resulted in the removal of tens of thousands of pampas plants.

Scotch broom (Cytisus scoparius) is particularly invasive in the Barrington Tops national park area, in NSW, across an area of about 50 000 hectares. A major protective weed eradication and integrated management programme has been implemented there.

Bitou bush (Chrysanthemoides monilifera spp. rotundata) is listed as a key threatening species in NSW. It mainly invades dune vegetation systems, but also encroaches into coastal forest and woodland communities. Biological controls such as bitou tip moth have been used with some success, forming part of the management strategy there.

Boneseed (Chrysanthemoides monilifera spp. monilifera) is more widespread across various environments and is found in southern NSW, VIC, southeastern SA and TAS. Spread by seed, it invades a range of woodland and forest types. Biological controls have not been successful so far, and eradication is by conventional means, including fire.

Willows (Salix spp.) have been recognized as serious invaders of streams within many forested parts of southern Australia, with TAS, VIC, NSW and the ACT the most affected. Guidelines for identification and eradication of particular willow species from inappropriate environments have been prepared in a range of jurisdictions and eradication programmes have been implemented, particularly in the last five years. For example, an interstate cooperative programme has been conducted for willow removal in the Genoa River catchment in the eastern border region of NSW and VIC. The Tasmanian government has implemented restrictions on the import, sale, and planting of particular problematic willow species.

Pathogens

With the exception of the soil or water-borne pathogen Phytophthora cinnamomi - widely considered to have been accidentally introduced into Australia after European settlement - native forests, woodlands or plantations are affected mainly by indigenous plant pathogens. In plantations of non-native species, however, pests and pathogens are primarily of overseas origin. Table 2 contains an excerpt from a manual, "Forests and timber: a field guide to exotic pests and diseases" that was developed, as part of an overall exotic pest general early warning strategy, through consultation with a wide range of forest health scientists through the Forest Health Committee.

Table 2: The main insects and pathogens affecting forests in Australia

Source: "Forests and timber: a field guide to exotic pests and diseases", Australian Quarantine and Inspection Service (AQIS) website.

The root-rotting fungus Phytophthora cinnamomi (and a number of other Phytophthora species) kill a wide range of plants in susceptible areas (predominantly regions with more than 600 mm annual rainfall). Phytophthora cinnamomi has caused significant death of commercially important eucalypt species, such as jarrah (E. marginata) in WA, silvertop ash (E. sieberi) in southeastern Australia and young plantations of Gympie messmate (E. cloeziana) in QLD.

However, the most significant impacts are on biodiversity. Quantitative nationwide data are limited in their capacity to clearly distinguish the area and impacts in forests and woodlands from those in vegetation types such as heathlands. As many as 2 000 of the estimated 9 000 native plant species in the southwest of WA are susceptible to P. cinnamomi root rot disease and 39 threatened species are currently identified for protection from P. cinnamomi in TAS.

Phytophthora is a "key threatening process" in the Environment Protection and Biodiversity Conservation Act 1999, with a National Threat Abatement Plan for P. cinnamomi released in 2001. P. cinnamomi spread is controlled through hygiene protocols and management zones for the protection of threatened flora. Forestry, national park and local agencies in many jurisdictions have implemented plans to restrict pathogen spread. Intensive monitoring is undertaken in WA to identify the distribution of the disease in commercial forests and conservation areas and to designate protectable areas free of the pathogen.

A wide range of chronic or episodic crown dieback syndromes, often with significant tree mortality and accompanying impacts on ecosystems, occur to some degree in native forests and woodlands in all states. These are usually of complex origin, associated with combinations of factors such as: climatic stresses, land management practices, severe insect attacks and imbalance in insect predator levels.

Pathogenic fungi are not generally the primary factors, but canker-causing fungi - including Cryphonectria eucalypti (formerly Endothia gyrosa) and Botryosphaeria spp. - often have a significant secondary role. Definition of the syndromes and causal agents is often difficult and it is hard to clearly delineate the affected areas because of the wide range of land tenures involved.

Rapid expansion of native hardwood plantations in Australia has seen defoliating diseases become more significant. These are mostly episodic, depending on factors such as local climatic conditions, age, and the genetic composition of plantations.

While few fungal leaf diseases of eucalypts are economically damaging in commercial or environmental plantations, significant exceptions include several native Mycosphaerella spp. - the most serious being M. cryptica and M. nubilosa in young blue gum (E. globulus and E. nitens) plantations in southern Australia, Cylindrocladium quinqueseptatum in young eucalypt plantations in northern QLD, and Quambalaria pitereka in young spotted gum (Corymbia spp.) plantations in humid areas of NSW and QLD. Control measures include selection for genetic resistance to these foliar pathogens in plantations. Such diseases are less debilitating in natural forests and woodlands, where inoculum levels are usually low.

In cool temperate rain forest in TAS and VIC, myrtle wilt disease (caused by the native pathogenic fungus Chalara australis) attacks myrtle (Nothofagus cunninghamii), through wounds in stems and branches. Although myrtle wilt disease is widespread in undisturbed forest, damage to trees associated with road building and logging can increase the activity of this disease.

Root and butt rots caused by Armillaria spp., most significantly A. luteobubalina in eucalypt forest predominantly in southern Australia, cause small patch deaths of a range of plant species. Ganoderma spp., Rigidoporus vinctus, and Phellinus noxius in QLD kill a low, but increasing, percentage of trees in a similar way. Species affected include: young hoop pine (Araucaria cunninghamii), rain forest species, eucalypts and Acacias - especially in regrowth forests or second rotation plantations.

Acacia species in a wide range of land tenures and forest ecosystems are affected by species of native gall or phyllode rust fungi Racospermyces and Uromycladium. These can cause severe defoliation and effects on form, and even tree death. Impacts in natural stands are usually small, whereas in plantations, for example of Acacia mangium in northern Australia, severe levels of phyllode rust have warranted investigations for disease resistance.

In Pinus radiata plantations of up to 15 years of age, in areas where climatic, topographic and stand conditions are suitable, the exotic needle-cast fungus Dothistroma septospora - first recorded in Australia in 1975 - is a primary pathogen able to cause severe needle loss. The northern tablelands of NSW and small areas in southeast QLD are worst affected, but the disease is also sometimes significant in the tablelands of southern NSW and in northeast VIC. Thinning is used as an ameliorative measure, but aerial spraying with low concentrations of fungicide is also occasionally carried out. The disease is absent from SA and WA - and, although present in TAS, causes little damage. Relatively little significant needle blight has occurred during the past five years because of drought conditions over much of the P. radiata estate. Planting of disease-resistant stock is currently undertaken to reduce disease impacts in highly prone locations in northern NSW.

The fungus Sphaeropsis sapinea is associated with top death and occasional mortality of P. radiata, usually on drought-prone sites, in most states of Australia. Needle-cast associated with the fungi Cyclaneusma minus and Lophodermium spp. also occurs in many P. radiata growing regions.

Key institutions involved in Forest Invasive Species strategies

Commonwealth Government

There are two portfolios within the Commonwealth Government that have legislative responsibilities for addressing invasive plant pests:

• Environment Australia (EA; www.ea.gov.au). Legislative powers are provided under the Environment Protection and Biodiversity Conservation Amendment (Wildlife Protection) Act of 2001; and

• Agriculture, Fisheries and Forestry - Australia (AFFA; www.affa.gov.au). The legislative backing for the plant protection activities of this department is provided under the Quarantine Act of 1908.

Within AFFA there are three functional groups with responsibilities for matters relating to plant health. These are:

• Biosecurity Australia (BA), which is responsible for quarantine policy and negotiations relating to access to Australia’s - and other countries’ - markets, for commodities that carry a quarantine risk;

• the Australian Quarantine and Inspection Service (AQIS) with responsibility for enforcing quarantine legislation at the border, including surveillance of our sparsely populated northern borders and cooperative programmes with Indonesia, East Timor and Papua New Guinea to survey for selected exotic pests; and

• the Office of the Chief Plant Protection Officer (OCPPO), which is a relatively new unit within AFFA, (having been established in 1998), with the responsibility for coordinating national responses to exotic plant pest emergencies. Among other things, the OCPPO works with countries of the Asia-Pacific region to improve the flow of information on plant pests and assist with the development of basic plant health infrastructure - particularly diagnostic capability and the development/rehabilitation of pest collections and plant disease herbaria. These collections are fundamental to the capacity of countries needing to describe the health status of their agricultural and forest industries.

Plant Health Australia

Plant Health Australia (PHA, www.planthealthaustralia.com.au) is a public company that was established in 2000 to:

• be the key adviser on plant health issues for industry and government;

• promote international and domestic confidence in Australia's plant health status;

• develop effective and auditable plant health management systems; and

• commission, coordinate and manage agreed plant health programmes.

Members of PHA include the Commonwealth Government, all state/territory governments, and at least 15 peak industry bodies. The joining of forest industries is currently under negotiation.

State and territory governments

The state and territory departments, which maintain responsibility for invasive plant pests, have a large network of regional offices that undertake a range of plant health activities, including: diagnostics, surveillance, collection management and research.

In many states, the management of agricultural, forest and environmental pests is the responsibility of separate departments, cooperating to meet common objectives in maintaining high standards of plant health. The principal agencies responsible for the management of invasive pests of agriculture and forestry in each state/territory are listed in Table 3.

Table 3: Overview of the principle agencies involved in invasive species management in Australia

Institutional responsibilities for invasive plant pests

Under the Australian Constitution, agricultural production, including plant health, is a state/territory matter. Figure 1 shows a map of Australia indicating the state and territories.

The Commonwealth (Federal) Government’s interest and accountability for plant health stems from its responsibilities for trade and quarantine. This dichotomy in responsibilities for plant health matters, including surveillance for exotic plant pests (which includes insect pests, plant pathogens and weeds) and their management within Australia, has been bridged through consultation and various institutional arrangements that have evolved over time.

Figure 1: Map of Australia showing the state and territory borders.

The responsibilities of the different parties involved in managing plant health and responding to invasive plant pests in Australia can be summarised as follows:

The role of the Commonwealth is to:

• provide quarantine controls at Australia’s international borders to reduce the risk of entry of exotic plant pests;

• provide surveillance across north Australia, the Torres Strait and through cooperative programmes, Indonesia, East Timor and Papua New Guinea;

• provide national surveillance programmes at high-risk ports of entry for exotic fruit flies and Asian gypsy moth;

• convene and chair Consultative Committees responsible for national response actions for new incursions;

• participate in funding of national response programmes;

• provide information to international trading partners about the plant health status of Australia;

• manage any international trade problems related to outbreaks of pests in Australia; and

• fulfil Australia’s obligations under the International Plant Protection Convention (IPPC) and Convention on Biological Diversity (CBD). Under the CBD, contracting Parties have an obligation to prevent the introduction of, control or eradicate those alien species that threaten ecosystems, habitats and species.

The role of the states/territories is to:

• manage conditions for interstate trade of plants and plant products;

• manage any interstate trade problems associated with outbreaks of pests;

• provide general surveillance;

• maintain capacity to diagnose plant pests;

• maintain adequate pest records and collections/disease herbaria; and

• participate in Committee processes and funding of national response programmes.

The role of industry is to:

• provide appropriate control of endemic pests in commercial agriculture;

• meet interstate and international phytosanitary conditions for trade; and

• report suspect exotic pests when detected.

Ministerial Councils and Advisory Committees

The peak government bodies are the Ministerial Councils dealing with primary industries and natural resource management. Plant health issues fall within the scope of the Primary Industries Ministerial Council (PIMC), with the exception of weeds, which are the responsibility of the Natural Resource Management Ministerial Council.

Membership consists of Commonwealth, state and territory Ministers responsible for agriculture and the environment, respectively. Under these are a range of Ministerial advisory committees, such as the Primary Industries Standing Committee (PISC), consisting of Commonwealth and state/territory departmental heads; Primary Industries Health Committee; and technical committees such as the Forest Health Committee (FHC).

These committees advise the Standing Committees and Ministerial Councils on all aspects of response action required for the containment or eradication of exotic pests, including the need for international or interstate quarantine action, as well as legislative, financial, administrative and technical (including research) considerations. Subordinate bodies of the technical committees include:

Forest Health Committee

The FHC provides a forum for dealing with forest health issues, particularly quarantine and incursion management at national level.

The FHC Terms of Reference include:

• preparedness to deal with incursions of exotic pathogens and pests of forests and forest products;

• to undertake a continuing review of the pests and pathogens affecting Australian forests (native, commercial and amenity) and forest products (including imported timber) with particular regard to their incidence and economic and environmental importance;

• to consider and advise the Primary Industry Standing Committee (PISC), Forest and Forest Products Committee (FFHC), other Standing Committees and industry on developments in the fields of forest pathology and forest entomology. This includes matters relating to research, surveillance, diagnostics, extension training and regulatory issues where appropriate, and on all aspects of action required for control, containment or eradication of specific pests and diseases - including the need for new or changed international or interstate quarantine action;

• to consider and advise the PISC, FFHC, other Standing Committees and industry on the prospects and actions required for the integrated management of pests and pathogens of forests and forest products; and

• to assist government through the PISC and FFPC in the development of forest health and plant quarantine policies.

The FHC is comprised of state and territory representatives, CSIRO (and other research providers), AQIS, Biosecurity Australia, OCPPO, Environment Australia, Research Working Group and co-opted members. Representatives from the Plant Health Committee and New Zealand Forest Health are observers.

Regulations involved in invasive species strategies

Recommendations made by the Consultative Committee for response actions are carried out under state legislation, which for QLD is the Plant Protection Act 1989, for VIC is the Plant Health and Plant Products Act 1995 and so forth. Table 4 gives an overview of relevant legislation regarding invasive species and the various different administrative agencies.

Table 4: Australian legislation with regard to invasive species.

*There are other relevant acts, such as the state/territory environmental protection legislation. Specific pest responses are carried out under state and territory legislation.

These Acts enable government agencies to:

• enter properties to survey for an exotic pest;

• inspect, treat and take samples of plants or plant products;

• establish quarantine zones;

• restrict the movement of plants, plant products, equipment, vehicles and other sources of contamination;

• issue orders for the destruction of infested/infected plant material; and

• require owners of affected premises to implement quarantine or pest eradication measures.

In the event of a new incursion, it is primarily the state plant protection legislation that will be utilized to respond. The Commonwealth Quarantine Act 1908, Quarantine Proclamation 1998 and Environment Protection and Biodiversity Conservation Amendment (Wildlife Protection) Act 2001 operate alongside the relevant State Plant Health Acts and have broad coverage over matters of quarantine and environmental protection in Australia. In cases where a state law is inconsistent with a Commonwealth law, however, the Commonwealth law prevails.

Key elements of a biosecurity strategy

The framework for preparing and responding to exotic pests can be seen in Figure 2. This framework includes three major stages that take into account input into the overall outcome of reducing the risk and impact of exotic pests before the pest becomes established (Pre-event), when the pest is detected (Response), and after the pest has been eradicated or managed (Recovery).

Figure 2: The framework for preparing and responding to exotic pests in Australia

Quarantine activities

Quarantine controls on the entry of plants and plant products at the border, regulated by AQIS, and quarantine policy based on risk assessment, conducted by BA, are designed to identify and minimize the threats to Australian forests and forest industries from incursions of exotic pests. AQIS has been allocated an additional A$281.4 million (US$196 million) from 2001-02 to 2004-05, to significantly increase Australia’s border protection operations.

Australia is bound by the WTO-SPS Agreement, which sets conditions, based on scientific principles and risk assessment, to protect agricultural industries from exotic pests, and at the same time facilitate trade in agricultural commodities. Approval is subject to BA assessing that applications for entry pose an acceptable level of risk, taking into account matters such as:

• the plant health status of agricultural industries in the country or region from which the commodities are to be sourced;

• the likelihood of pests of concern being transported with commodities and establishing in the importing country;

• potential damage that introduced pests might cause to crops and native flora; and

• the efficacy of phytosanitary treatments that might be used to manage identified risks.

Assessments made by BA in response to applications to access the Australian market are known as Import Risk Assessments (IRAs). In recent years, Australia has improved the transparency of its IRA process and encourages greater input from stakeholders.

Over the last two years, BAs forest health work programme has included: progression of an IRA for five coniferous timber species from three countries, conducting Pest Risk Assessments (PRA) of pine pitch canker and sudden oak death wilt, and risk assessments with regard to imports of thuja logs and oversized kwila timber for construction.

BA is also currently conducting reviews on the importation of Acacia and Casuarina seed for sowing, in response to advice received from the Forest Germplasm Workshop of January 2002. It continues to progress a coniferous timber IRA consistent with international obligations, and has been involved in further work on a suspended set of draft wood packing guidelines in which the efficacy of proposed treatments with regard to pathogens is now subject to review.

Future forestry related work for BA includes; a review of the species listed as being of forest and amenity significance (which require a two year Post Entry Quarantine), progression of the coniferous timber IRA, further reviews for emergent Phytophthora species and nursery stocks, and continuing to provide advice to AQIS on timber imports and exports on an as-needed basis.

Surveillance

The present system for detecting exotic pest incursions in Australia is based on a combination of specific monitoring activities, general surveys across northern Australia, state government and industry awareness programmes and ad hoc reporting (from growers, members of the public, etc).

The success of incursion management relies heavily on grower participation in passive or general surveillance to increase the chances of early detection of exotic pests. Currently the AFFA and PHA, have developed a national plant pest hotline telephone reporting system, with associated targeted publicity awareness material, to more effectively capture potential detection information through general surveillance activities.

States have a major role in surveying forest health. Annual surveys of plantations and routine general surveillance of commercial forests is conducted by state forest agencies in NSW, QLD and TAS with other states and territories carrying out various forest surveillance activities. The surveys in native forests target key areas and perceived high-risk zones. In SA, a Forest Health Monitoring Kit has been developed to help staff sample and monitor plantations and identify insect pests and diseases. In WA, a system targeting specific forest sites - known as FORESTCHECK - is carried out.

The Commonwealth, through state government agencies, runs a national trapping programme for Asian gypsy moth. AFFA has produced a field guide to exotic pests of forest and amenity trees and timber to encourage early reporting of suspected outbreaks of these pests.

In addition, during 1999/2000, AFFA funded a trial forest health surveillance programme in QLD. The work was conducted by staff in the Forest Protection Programme of the Queensland Forestry Research Institute (QFRI). Five ports were targeted: shipping and airport surrounds in Brisbane and Cairns; and shipping port surrounds in Gladstone, Townsville and Bundaberg. This was the first serious attempt to systematically survey areas of highest-hazard with respect to forestry quarantine. Although no exotic pests of forestry significance were found, the surveys did demonstrate the capability to detect such pests, if present.

Forestry Tasmania is conducting a trial to develop an effective Port Environ/Urban Surveillance Programme, which uses pheromone trapping for some key insect pests, sentinel sites of key host species and a survey of high risk areas near ports.

The national Asian gypsy moth trapping programme serves as an early warning system to detect incursions of exotic Lymantrid species entering through Australian ports. It is funded by AFFA and coordinated by the OCPPO. Ships and shipping containers are seen as likely pathways for entry so the trapping programme is centred in the first ports-of-call. The programme is based on a network of Delta traps on a 1-kilometre grid out to 2 kilometres from port facilities and a 2-kilometre grid from the boundary of the 2-kilometre zone out to 5 kilometres from the port facility centre. Actual trap numbers per port facility vary, with a maximum of 40 traps per port. The surveillance network includes over 450 traps. Field monitoring and servicing of traps is carried out by state agriculture or forestry agencies.

The Northern Australia Quarantine Strategy (NAQS) is a programme of AQIS that is responsible for monitoring and surveillance to provide advanced or early warning of exotic pest threats. The purpose of the programme is to limit the opportunity for exotic pests to establish and remain undetected in remote areas. Surveillance targets are based on pest risk analyses that identified northern Australia as a pathway for entry of exotic pests of major plant host groups.

Exposure of NAQS scientists to exotic pests in the region builds expertise and increases confidence that exotic pests will be detected in regular surveys across northern Australia. The onshore component of the NAQS monitoring and surveillance programme covers a coastal band - 20 kilometres in width - across northern Australia from Broome, in the west, to Cairns, in the east. NAQS activities also extend offshore to East Timor, Papua New Guinea and Indonesia. The initiative includes trapping for exotic fruit flies on the islands of the Torres Strait, as well as a public awareness programme known as Top Watch.

Diagnostics

A decision on whether to eradicate, contain or manage an outbreak of an exotic pest must be made quickly and is dependent on the ability to obtain a rapid and accurate diagnosis of the organism involved. Diagnostic services in Australia are provided via a combination of government laboratories (state agencies and CSIRO), commercial laboratories, universities, and pest and disease specialists who perform diagnostic duties as part of their jobs. A recent assessment of the current status of diagnostic capacity in Australia found that:

• although overall resources allocated to plant pest diagnostics are substantial, resources in certain disciplines, especially nematology and bacteriology, have declined in recent years, potentially compromising national capability in these areas; and

• documented procedures for identifying exotic pests of concern are not generally available and there is little quality control to ensure the delivery of standardized techniques such as those used in veterinary laboratories in Australia.

The OCPPO and PHA have recognized the importance of strengthening diagnostic capacity and are committing resources to the development of national diagnostic standards for priority exotic plant pests as well as a diagnostic network to identify and network domestic and international diagnostic expertise to be used in pest identifications. For forestry, diagnostic protocols being developed include: pine pitch canker (Fusarium circinatum), Eucalyptus rust (Puccinia psidii) and Bursaphelenchus spp.

National pest reporting and recording

A sound knowledge of the pest status of Australia's plant industries and native flora is essential if costly false alarms - arising from findings of suspected new invaders - are to be avoided. Clearly, if we don’t know what pests are endemic, it is difficult to determine - with any confidence - the status of a newly discovered organism. This is why arthropod and pathogen collections and disease herbaria containing validated and well-curated specimens are critically important. These collections hold information on a pest’s distribution, life cycle and host(s) and provide a basis against which to compare unknown organisms and facilitate the accurate identification of suspected exotic pests.

Reference collections holding records of economically important pests are held by numerous organizations throughout Australia. The OCPPO and PHA are managing a project to improve the accessibility of these records through the development of an Australian Plant Pest Database, which links the diverse, geographically scattered databases throughout Australia, so that all of the available data can be accessed from a single point via the internet. Support is also being provided for data entry and some validation of existing records.

Response planning/programmes

In 2000, the national Forest Health Committee released a Generic Forest Incursion Management Plan (GIMP) to facilitate preparedness and response actions to potential new incursions of exotic pathogens or invertebrate pests into Australia. Currently, the PHA, in association with various members, is developing specific industry biosecurity plans that, at this time, do not include forest industries, but may serve as a model for future development of emergency response planning. Key elements to developing appropriate response plans include:

• identification and assessment of pest risks;

• risk mitigation strategies;

• surveillance and diagnostic strategies;

• response procedures and defined roles and responsibilities; and

• termination and post eradication strategies.

Response system for forest pests

The response to a new incursion begins when a suspect exotic plant pest is reported to state and national authorities. There are a number of response phases:

• notification and initial response: a grower or member of the public may find a pest, or some unusual symptoms, on plants and report this to the local Department of Agriculture office, or equivalent. Officers will investigate and samples will be taken and sent to diagnostic laboratories. If an exotic pest is suspected, the Chief Quarantine Officer in the state is notified, who will in turn notify the Chief Plant Protection Officer (CPPO) located in AFFA. The CPPO will then notify Plant Health Committee members, other relevant state/Commonwealth agencies and industry. Steps will also be taken to verify the initial identification. This may involve sending samples interstate or overseas.

• containment and scoping: state authorities will generally implement a number of containment measures to prevent further spread of an exotic pest beyond the known outbreak site. Depending on the nature of the incursion, areas around the detection site may be immediately quarantined and restrictions may be imposed on the movement of host material from the quarantine area. Surveys and trace backs will be conducted to determine the geographic extent of the outbreak and its severity.

• determine feasibility of eradication: The CPPO will convene a Consultative Committee to advise on appropriate response actions. The Consultative Committee will include representatives from the OCPPO, state/territory agencies, Biosecurity Australia and industry. A decision on the feasibility of eradication will consider:

  • biology and mobility of the pest;

  • host range and presence/absence of vectors;

  • extent of the outbreak (is it too widespread?);

  • accessibility of the outbreak site (urban or commercial environment?);

  • likelihood of repeated incursions;

  • availability and effectiveness of control options;

  • sensitivity of monitoring techniques; and

  • cost-benefit analysis of response options.

• eradication vs. management: the Consultative Committee will make a recommendation to the relevant Standing Committee on whether an eradication programme should proceed, what this would involve, a budget for response actions during the current financial year, and indicative costs for subsequent years. The Primary Industries Ministerial Council will make the final decision. In cases where the Consultative Committee determines that eradication is not feasible or justifiable, Commonwealth involvement in the outbreak ceases (except when there are implications for international trade), and the states assume responsibility for ongoing management of the pest.

Sources of information

Statistics supplied by ABARE, BRS and AQIS.

National Forest Inventory Australia website link -
http://www.affa.gov.au/content/output.cfm?ObjectID=C3ABDD30-E8D3-439C-8E37AFE6D01F0C4F&;contType=outputs

National Forest Inventory Australia State of the Forest Report (available from NFIA website)

Research Working Group of Forest and Forest Wood Products Committee

Agriculture, Fisheries and Forestry Australia (AFFA) website link - www.affa.gov.au

The Office of the Chief Plant Protection Officer (OCPPO) website link - www.affa.gov.au/planthealth

Australian Quarantine and Inspection Service (AQIS) website link - www.aqis.gov.au

Appendix 1 - breakdown of pests, processes or agents impacting on forested areas

· Vertebrate pests

· Diseases and pathogens

· Invertebrate pests

· Plant pests

1 = Occurs but is not widespread, has little impact, and requires little or no control.
2 = Extent and impact are limited but control measures are extensive.
3 = Widespread or having adverse impacts.
4 = Widespread and having adverse impacts.
5 = Very widespread and having severe adverse impacts.

Appendix 2: Generalized model of forest pest incursion management procedure

Cambodia: The Mimosa pigra report

Samreth Vanna and Ket Nang
Department of Forestry and Wildlife
Ministry of Agriculture Forestry and Fishery

Introduction

Mimosa pigra is a plant native to South America, although it is now widely distributed throughout the tropics. It was introduced to Thailand in 1947 as a green manure and cover crop. Being prickly, it was thought it would restrict access to water banks and thus reduce erosion. It now covers large areas of standing waters and water banks. Since the 1980s, Mimosa pigra has been found growing rapidly in low-lying areas, especially along the Mekong River and areas surrounding Tonle Sap Great Lake. Locally the plant is known as ohyas, Vietnamese thorn, or giant thorn. In Cambodia, it interferes with irrigation systems (sediment accumulation), access to electric power lines, and is a safety hazard along roads. It also grows in fallow rice paddies making reclamation more expensive.

Mimosa pigra is a spreading thorny shrub, usually 2 metres tall, but it occasionally grows up to 6 metres. It forms dense, impenetrable, mono-specific thickets. It establishes along riverbanks and out into the drier floodplains. When it grows along water banks, it affects accessibility to water for stock, irrigation and the use of lakes and rivers for recreation purposes. Pastures are smothered, reducing available grazing area and stock mustering is difficult. In conservation areas, dense growth eliminates most other species and alters the natural habitat. One of the main problems of Mimosa pigra is that it forms dense monocultures and suppresses other vegetation, as well as impacting on aquatic habitats, because fish avoid areas infested with Mimosa pigra.

Purpose

The purpose of the investigation was to collect information on the distribution of Mimosa pigra in order to describe the problems this weed creates for farmers, and to update the knowledge of officials in the various Ministries involved with management of this species.

Methodology

In order to get information on Mimosa pigra we have:

• searched for information on the internet;

• prepared questionnaires for interviews with farmers;

• selected farmers to interview; and

• held discussions with representatives from the Ministry of Agriculture.

Results

Cambodia is rich in natural resources, such as inundated forests and fishing grounds. In addition, Cambodian soil is fertile almost all over the country. Unfortunately, over the past 15 years the existence of Mimosa pigra has disturbed agricultural work and is causing major concerns among Cambodian farmers. The taskforce members conducted field visits, to interview farmers involved in small-scale agricultural work, in an effort to find out how they handle the problems caused by Mimosa pigra.

According to some farmers, there is uncertainty about the origins of this thorny plant, as it was not found in Cambodia until quite recently. The plants have been observed for about the past 15 years. The plants are covered from stem to leaves by dense and hard thorns, making the plant unsuitable for animal fodder. Apparently the only beneficial use of the plant is as fuelwood.

Farmers find it hard to cultivate their crops because Mimosa grows considerably faster than agricultural crops. Small Mimosa plants grow and migrate rapidly into planted land where crops are developing. Agricultural crops can be overrun within four or five days, if farmers do not meticulously weed their land and ensure the removal of all the Mimosa plants - including the roots. Farmers have to spend a considerable amount of time and labour to clear, root out and plough many times to remove all of the roots, stems, stalks and leaves from their land; otherwise the plants will grow again quickly. When faced with a Mimosa infestation some farmers have been forced to leave their land for other vacant land free of the plant, if they do not have adequate labour and financial resources to remove Mimosa from their land.

The following steps are taken by most farmers to combat Mimosa infestation:

• in the early stages, they clear all the Mimosa from their land, as soon as they observe the plant;

• if the plant is mature, they have to cut it all out and pull out all the roots, before it produces flowers and fruits. Mimosa plants with ripe fruit should never be burned as this assists in the further spread of this plant;

• it is important to remove all stalks or stems or the plant can sprout again. The roots need to be removed prior to flooding; otherwise they will decay in the soil resulting in additional problems.

There are chemicals available to combat Mimosa, however these are expensive and have a negative impact on the environment.

Conclusions and recommendations

Based on the results of our survey, the following conclusions can be made:

• Mimosa pigra is a major problem for many farmers in Cambodia. They are worried about it every year;

• Mimosa pigra appears to be well adapted to the ecological conditions in Cambodia; and

• eradication of Mimosa from infested fields is a time consuming and labourious task.

The following recommendations have been made on the basis of the survey:

• farmers should endeavour to eradicate Mimosa pigra, whenever it appears on their land;

• Mimosa could be used for fuelwood instead of using trees from the flooded forests. This would help to reduce the occurrence of Mimosa pigra;

• The Ministry of Environment and Ministry of Agriculture and Forestry should be responsible for updating knowledge of Mimosa pigra, making plans for dealing with the problem, and providing information to farmers; and

• farmers should exchange experiences and information with each other.