Threat abatement plan for disease in natural ecosystems caused by



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Threat abatement plan for disease in natural ecosystems caused by Phytophthora cinnamomi

January 2014

© Copyright Commonwealth of Australia, 2014

ISBN: 978-1-921733-93-2

The Threat abatement plan for disease in natural ecosystems caused by Phytophthora cinnamomi is licensed by the Commonwealth of Australia for use under a Creative Commons By Attribution 3.0 Australia licence with the exception of the Coat of Arms of the Commonwealth of Australia, the logo of the agency responsible for publishing the report, content supplied by third parties, and any images depicting people.


For licence conditions see: http://creativecommons.org/licenses/by/3.0/au/.

This report should be attributed as ‘Threat abatement plan for disease in natural ecosystems caused by Phytophthora cinnamomi, Commonwealth of Australia, 2014’.

The views and opinions expressed in this publication are those of the authors and do not necessarily reflect those of the Australian Government or the Minister for the Environment.

The contents of this document have been compiled using a range of source materials and are valid as at


August 2013.

While reasonable efforts have been made to ensure that the contents of this publication are factually correct, the Commonwealth does not accept responsibility for the accuracy or completeness of the contents, and shall not be liable for any loss or damage that may be occasioned directly or indirectly through the use of, or reliance on, the contents of this publication.

Table of Contents


Threat abatement plan for disease in natural ecosystems caused by Phytophthora cinnamomi 1

Table of Contents 2

1. Introduction 3

1.1 Threat abatement plans and implementation 4

1.2 The pathogen 4

1.3 Impacts of Phytophthora cinnamomi 6

1.3.1 Ecological impacts on plants 6

1.3.2 Ecological impacts on wildlife 7

1.3.3 Impacts on matters of national environmental significance 7



1.4 Managing the threat 8

1.4.1 Minimising the spread 8

1.4.2 Mitigating the impact 10

1.5 Climate change 12

2. Objectives and Actions 13

Objective 1: Identify and prioritise for protection biodiversity assets that are, or may be, impacted by Phytophthora cinnamomi 13

Objective 2: Protect priority biodiversity assets through reducing the spread and mitigating the impacts of Phytophthora cinnamomi 14

Objective 3: Communication and training 16

Research actions 18

3. Duration, Review, Funding and Implementation 21

3.1 Duration and review of the plan 21

3.2 Funding and implementation 21

4. Glossary and Abbreviations 22

5. References 24

Appendix A 28

Threatened flora species known to be susceptible to Phytophthora cinnamomi 28

Appendix B 32

Threatened ecological communities listed under the EPBC Act that may be impacted by Phytophthora cinnamomi 32

1. Introduction

This national threat abatement plan (TAP) has been developed to address the key threatening process ‘Dieback caused by the root-rot fungus1 Phytophthora cinnamomi, which is listed under the Commonwealth Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act).

The TAP establishes a national framework to guide and coordinate Australia’s response to P. cinnamomi. It sets out the actions necessary to abate impacts of the listed key threatening process and was developed to comply with the requirements under the EPBC Act for the development of threat abatement plans. It identifies the research, management and other actions needed in Australia’s response to this pathogen and replaces the threat abatement plan published in 2001 (Environment Australia, 2001).

The plan has been developed with the involvement and cooperation of a broad range of stakeholders, but the making or adoption of this plan does not necessarily indicate the commitment of individual stakeholders to undertaking any specific actions. Proposed actions may be subject to modification over the life of the plan due to developments in understanding of the organism and its impacts.

The Australian Government Department of the Environment (Department of the Environment) is responsible for preparing this TAP. Its development has been informed by:

• the current threat abatement plan (published in 2001)

• a review and evaluation of the 2001 TAP undertaken by the Australian Government (CPSM, 2006)

• information provided by key stakeholders between 2010 and 2013.

This plan should be read in conjunction with the document ‘Background: Threat abatement plan for disease in natural ecosystems caused by Phytophthora cinnamomi’ (the background document) (Department of the Environment, 2014). The background document provides information on the scope of the problem; the characteristics, biology and distribution of the pathogen; impacts on the environment and management practices (as at 2013).

The goal of this TAP is to identify and protect environmental assets (threatened species and ecological communities listed under the EPBC Act and other matters of national environmental significance) from the impacts of P. cinnamomi. It integrates: strategies to prevent P. cinnamomi spreading into areas that are free of disease; strategies to reduce the impacts in infested areas; and recovery actions for the conservation of biodiversity assets currently being impacted.

The Department of the Environment recognises that a number of the state and territory governments that own land impacted by P. cinnamomi have developed management plans and operational guides to abate this threat within their own jurisdictions. This TAP aims to complement state and territory approaches to managing P. cinnamomi.

Although this TAP applies to P. cinnamomi, the Department of the Environment acknowledges that recent diagnostic techniques have allowed other species of Phytophthora to be identified in Australia. Some of these species may be widespread and can lead to disease impacts similar to P. cinnamomi within native ecosystems. For further information on these species, a reference list is provided at Appendix B in the background document (Department of the Environment 2014). The control of pathways for the spread of P. cinnamomi and the development of improved control and remediation tools and techniques will also reduce the potential spread and impacts of other Phytophthora species.

1.1 Threat abatement plans and implementation

The EPBC Act prescribes the process, content and consultation to be followed when making a TAP to address a listed key threatening process. Under Section 270(A) of the EPBC Act, the Australian Government:

• develops TAPs where the Minister agrees that the making of a TAP is a feasible, efficient and effective way to abate a key threatening process.

Under Section 269 of the EPBC Act, the Australian Government:

• implements TAPs to the extent they apply in areas under Australian Government control and responsibility. Australian Government agencies must not take any actions that contravene a TAP

• seeks the cooperation of the affected jurisdictions in situations where a TAP applies outside Australian Government areas in states or territories, with a view to jointly implementing the TAP.

The success of this TAP will depend on a high level of cooperation between all key stakeholders, including:

• Australian Government departments and agencies

• state and territory conservation and natural resource management agencies

• local governments

• research institutes

• industry and entrepreneurs, including the forestry, garden and nursery, mining, and road construction industries

• the general community, including non-government environmental organisations and private conservation land management bodies, private landholders, Indigenous communities and natural resource management groups.

It will be important that land managers assess the threats and impacts of P. cinnamomi and allocate adequate resources towards effective on-ground prevention of spread and management of impacts, improving the effectiveness of prevention and management programs, and measuring and assessing outcomes.

In order to successfully implement this TAP, the Department of the Environment will:

• coordinate its implementation as it applies to Commonwealth land and act in accordance with the provisions of the TAP, as required under the EPBC Act

• seek stronger coordination of national action on P. cinnamomi

• draw on expertise from state and territory agencies and non-government organisations

• encourage involvement of key stakeholders and experts in P. cinnamomi related research and management.

The Australian Government will monitor the uptake and effectiveness of management actions by all parties as part of a review of the TAP under Section 279 of the EPBC Act. Where the Australian Government and state and territory governments have mutual obligations, negotiation of appropriate actions and funding of management actions will be undertaken.

1.2 The pathogen



Phytophthora is a major genus within the diploid, alga-like phylum Oomycota (Cooke et al., 2000). This group is currently referred to as water moulds and, although it was previously referred to as fungi, in taxonomic terms it is more closely related to algae. As P. cinnamomi has the ability to cause plant disease and plant death, this document refers to this species of water mould as a pathogen. At least 32 species of Phytophthora occur in various parts of Australia. Other species of Phytophthora, including P. cryptogea, P. megasperma, P. multivora and P. arenaria are also known to cause significant damage in the wild, particularly in Western Australia. However, much more extensive damage has resulted from the presence of P. cinnamomi.

P. cinnamomi was probably introduced to Australia with European settlement and since the mid-1960s, has been recognised as a serious threat to many native plants and ecosystems, important crops and horticultural plants.

P. cinnamomi is known to occur in all Australian states and territories; with the exception of the Northern Territory, where it is generally accepted that the environmental conditions are not conducive to the pathogen’s establishment and persistence in susceptible native plant communities. The area of Australian native vegetation affected by Phytophthora species exceeds a million hectares, and continues to increase. It has been reported that more than 1 million hectares are affected in Western Australia alone. Recorded isolations, records of impact and a broad climatic envelope of Phytophthora species susceptibility in Australia are depicted in a map in the background document (Department of the Environment, 2014).

The pathogen is now well established in many of the country’s higher rainfall areas (areas with a mean annual rainfall greater than 600 millimetres). Although higher rainfall areas are more favourable, the distribution of P. cinnamomi has been reported in areas with average yearly rainfall as low as 400 millimetres (Brasier and Scott, 1994). The most favourable conditions for spore production are free water and warm temperatures. Soils that are neutral pH to acidic are most favourable for the sporulation and survival of P. cinnamomi (Zentmyer, 1980).

The development of the disease, Phytophthora dieback, requires a number of factors that must operate in concert. These are: the presence of the pathogen; the presence of susceptible host plant species; and environmental conditions that favour infection and subsequent reproduction and spread of the disease (Garkaklis et al., 2004).

Plants become visibly diseased when infection results in the impairment of the plant’s physiological and biochemical functions. Roots are a primary site of infection and therefore uptake of water is one of the first functions affected. This is why symptoms of P. cinnamomi infection have similarities, at least initially, with those of water-stress. For susceptible species, apparently healthy plants (in groups or individually) can suddenly die. Less susceptible species can show crown decline symptoms, including leaf yellowing and death of primary leaf-bearing branches. Epicormic branches with smaller leaves can develop, and over time epicormic branches will decline, with an overall thinning of the crown. Trees with such symptoms can take a number of years to decline and die. The removal of bark at the base of trees just above or below the soil line can reveal areas of necrosis. These necrotic areas effectively girdle the trees and cause death.



P. cinnamomi can be spread in water, soil or plant material that contains the pathogen and dispersal is favoured by moist or wet conditions. It can be carried in both overland and subsurface water flow and by water moving infested soil or organic material. Native and feral animals have been implicated in spreading P. cinnamomi, particularly where there are digging behaviours. Humans, however, have the capacity to disturb and transport more soil than any other vector. Most of the large centres of infestation that exist today in southern temperate Australia occurred as a result of human activity, often as a direct result of the introduction of infested soil or road-building materials to vulnerable un-infested areas (O’Gara et al., 2005b). A list of human assisted spread mechanisms is in section 1.4 of this TAP.

Zoospores from the pathogen can swim short distances in free water. P. cinnamomi grows through roots and can spread to the roots of adjacent plants where root-to-root contact occurs. Root-to-root movement of the pathogen is thought to be one of the major ways in which the pathogen moves upslope (O’Gara et al., 2005b). Under less favourable conditions, P. cinnamomi produces asexual reproductive structures known as chlamydospores, which can survive for several years until conditions improve. Recently, in Western Australia, P. cinnamomi has been shown to survive asymptomatically in a range of native annual and herbaceous perennial species (Crone et al., 2012; Crone et al., 2013a) and in some species to survive as a biotroph. In addition it can, in some hosts, produce numerous selfed oospores which would allow it to survive adverse conditions when necessary (Crone et al., 2013b). These research findings may have important implications for the future management of P. cinnamomi.

It is important to note the intractable nature of disease caused by P. cinnamomi, but also that actions which ameliorate its effects—particularly on endangered species and communities—are vital to the conservation of Australia’s biodiversity.

1.3 Impacts of Phytophthora cinnamomi

1.3.1 Ecological impacts on plants

Healthy natural environments provide a range of direct and indirect benefits, which are threatened by disease caused by P. cinnamomi. This disease is often difficult to detect and its impact may be significant before it is detected.

The consequences of infection of susceptible ecological communities include:

• a dramatic modification of the structure and composition of the native plant communities

• a significant reduction in primary productivity and functionality

• habitat loss and degradation for dependent flora and fauna.

Hardham (2005) suggests that P. cinnamomi is likely to infect over 2500 Australian native species. In the South-West Botanical Province Shearer et al. (2004) have shown that approximately 41per cent of 5710 vascular plant species are susceptible to the pathogen. The pathogen is a threat, or possible threat to 144 native plant species listed as threatened under the EPBC Act (see the list at Appendix A). It may threaten several of these plant species with extinction.

Susceptibility of plant species to disease caused by P. cinnamomi is complex, with considerable variation occurring within plant taxonomic units, making occurrence within a plant family or genus a poor predictor of species susceptibility (Shearer, 2004).

The Centre of Phytophthora Science and Management (CPSM) at Murdoch University has compiled lists of Western Australian native plant species that are resistant to disease caused by P. cinnamomi (Groves et al., 2009a, 2009b). This information is available on the Dieback Working Group website (http://www.dwg.org.au/). Lists of field-resistant upland tropical rainforest species from Queensland are presented in Worboys and Gadek (2004). The lists have been compiled from field observations of resistance and the results of controlled experiments. However, the classification of a plant as resistant to P. cinnamomi often depends on other environmental factors (including climate) which can influence susceptibility to the pathogen. A species’ resistance can also vary depending on the pathogen’s genotype (Howard, 2008). A plant species’ susceptibility occurs on a continuum between resistant and susceptible with genetic components within species, between species and within genera displaying variable susceptibility. As a result, a species should be considered as susceptible when greater than 50 per cent of the genetic population of the plant is killed when confronted by the pathogen.

Investigations over several years have discovered the mechanisms by which a limited number of plants are able to survive infection, including the activation of defence-related genes and signalling pathways, the reinforcement of cell walls and accumulation of toxic metabolites (Professor David Cahill, pers. comm., 2011). Genetically-based, intra-specific variation in resistance has been demonstrated in the Western Australia native hardwood, Eucalyptus marginata (jarrah) (Stukely and Crane, 1994), and in the exotic plantation species Pinus radiata (Butcher et al., 1984).

While P. cinnamomi directly threatens a range of individual plant species, it also threatens ecological communities and landscapes. Large areas of Western Australia, for example, where the pathogen is likely to have been present for over one hundred years, represent post dieback plant assemblages (Dr Joanna Young pers. comm., March 2012).

Indirect impacts on flora have also been demonstrated, for example, in South Australia, EPBC Act listed orchid species (for example Caladenia argocalla, C. behrii, C. rigida) are afforded some measure of protection from herbivores where they are found growing in close proximity to the fronds of Xanthorrhoea semiplana (grass trees). When grass trees become infected with P. cinnamomi and die, the orchids become exposed and are vulnerable to herbivory (Petit and Dickson, 2005).

Multiple processes may interact with P. cinnamomi to increase extinction risk (Barrett et al., 2008). For example, P. cinnamomi activity might be greater in some circumstances following a fire because there are fewer plants to use the available water and sites are more prone to water logging (Cahill et al., 2008).

1.3.2 Ecological impacts on wildlife

Although there has been a substantial amount of research on the effects of P. cinnamomi on vegetation in some states, there has been comparatively little work that has investigated the indirect effects of the disease on faunal populations and communities where food sources or habitat is threatened by the disease (Cahill et al., 2008).

Garkaklis et al. (2004) reviewed the literature on the responses of forest animal communities to the presence of P. cinnamomi. This review indicated that, for a range of forest fauna, serious impacts were either occurring or were plausible but not yet demonstrated. Many of these impacts will arise because of changes in species richness and composition, and alterations to the structural composition of habitats. Species likely to be affected include some listed as endangered under the EPBC Act.

An example recently demonstrated by Dundas et al. (2013), is Tarsipes rostratus (honey possum), that visits many taxa that are susceptible to Phytophthora dieback. The inevitable spread of Phytophthora and its associated changes to vegetation composition is postulated to result in the localised loss of resources for honey possums and is a concern for ongoing conservation management.

1.3.3 Impacts on matters of national environmental significance

EPBC Act listed threatened species or listed threatened ecological communities are matters of national environmental significance protected under the Act. Appendices A and B of this TAP provide details of listed threatened species and ecological communities that are being impacted or that have the potential to be impacted by P. cinnamomi.

Under the EPBC Act, P. cinnamomi is treated as a key threatening process as a result of these impacts or potential impacts, including the potential for the pathogen to cause native species or ecological communities not yet listed to become eligible for listing.

Other matters of national environmental significance impacted, or potentially impacted by the presence of P. cinnamomi (through destruction of vegetation and subsequent damage to an area’s significance) are:

• world heritage areas

• national heritage places

• Commonwealth heritage on Commonwealth lands

• Ramsar wetlands (i.e. wetlands listed under the Convention on Wetlands of International Importance).

P. cinnamomi is known to have impacted on the following world heritage areas:

• Wet Tropics World Heritage Area of North Queensland. More than 200 patches infected with P. cinnamomi have been found, mostly in wet notophyll vine forests above 700 metres on acid volcanic soils. These forests comprise 14 per cent of the World Heritage Area.

• Gondwana Rainforests of Australia World Heritage Area of northern New South Wales and southern Queensland.

• Greater Blue Mountains World Heritage Area. Detected in various sites including the Wollemi Pine (listed as endangered) site.

• Tasmanian Wilderness World Heritage Area. P. cinnamomi is widespread across Tasmania and also occurs within the World Heritage Area.

• Lord Howe Island World Heritage Area. P. cinnamomi has been recorded from one lease in the southern part of the island’s settlement area and could potentially spread to the Lord Howe Island Permanent Park Preserve on footwear or vehicles (DECCW, 2010).

National heritage places for which P. cinnamomi is a threat include:

• The Stirling Range National Park and Porongurup National Park in south-west Western Australia. P. cinnamomi is a significant threat to plant communities of outstanding richness and endemicity.

• The Grampians National Park (Gariwerd) in Victoria, where P. cinnamomi has been recorded at many sites and longer term studies have shown wide-scale changes in their floristic composition.

• Western Tasmania Aboriginal Cultural Landscape.

Ramsar listed sites known to be affected by P. cinnamomi include Lavinia Wetland on the north-east coast of King Island, Tasmania (Parks and Wildlife Service, 2000); the Lake Warden System at Esperance, on the south coast of Western Australia (DEC, 2009); and Forrestdale Lake in Perth, Western Australia (Conservation Commission of Western Australia, 2005).

Although not listed as a matter of national environmental significance under the EPBC Act, an area being significantly impacted by Phytophthora dieback that is of national importance is the Fitzroy River National Park in Western Australia. This area is a reserve site recognised under UNESCO’s2 Man and the Biosphere Program. The EPBC Act includes provisions for cooperative arrangements between the Commonwealth, states and territories in the development of biosphere reserves.

1.4 Managing the threat

Although P. cinnamomi can be eradicated from small sites and containment methods are available to prevent the spread of the pathogen (Dunstan et al., 2011) further work is required to:

• minimise the spread of P. cinnamomi to uninfested sites

• mitigate the impact of P. cinnamomi at infested sites.

In order to address the key threatening process listing for P. cinnamomi under Section 183 of the EPBC Act, priority must be given to mitigating the impact and minimising the spread of P. cinnamomi in areas containing biodiversity assets of high conservation value. These include areas that:

• contain threatened species or ecological communities susceptible to P. cinnamomi

• contain habitat susceptible to P. cinnamomi and critical to the survival of threatened fauna.

P. cinnamomi may cause native species or ecological communities not yet listed under the EPBC Act to become eligible for listing (in any category, other than conservation dependent). This means that it is also important to address the impacts and spread of P. cinnamomi in areas that, for example:

• support high plant species endemicity

• support high species diversity for a type of vegetation

• support significant remnant vegetation as per state or territory criteria

• are large, ecologically intact and mostly undisturbed

• support susceptible species listed as threatened at the state or territory level, but not under the EPBC Act.

1.4.1 Minimising the spread

Humans can spread P. cinnamomi further and faster than any other infestation vector. High risk activities for spread include:



a) Emergency and land management activities

• Fire management, including:

– emergency firebreak construction

– fire fighting using P. cinnamomi contaminated water and/or equipment

– movement of contaminated equipment into uncontaminated areas due to non-compliance with, or careless implementation of, hygiene procedures

• Flood mitigation works, involving:

– movement of contaminated gravel, sand, soil etc.

– movement of contaminated equipment

• Use of contaminated nursery material and soil disturbance associated with revegetation and restoration activities

• Weed and feral animal control activities



b) Recreational activities

• Camping

• Bushwalking, geocaching, rogaining, orienteering

• Fishing and marroning/yabbying

• Mountain bike riding

• Horse riding

• Recreational vehicles (for example motor bikes, quad bikes, four wheel drives).

• Trail biking

• Hunting

c) Commercial and other activities

• Environmental/ecological surveys or research activities (for example flora, fauna, vegetation mapping, geological surveying)

• Tourism, particularly ecotourism

• Timber and wild flora harvesting

• Defence Force training

• Mining exploration and mining

• Seed collecting

• Soil and gravel extraction

• Firewood cutting

• Apiculture (beekeeping)

• Road construction (widening, realignment, maintenance)

• Maintenance of recreational tracks and walking trails

• Construction of straight line infrastructure (for example powerlines and telecommunication structures)

• Propagation and distribution of infected plants, soil and mulch for commercial purposes (for example nursery and gardening industries)

The limited management options available focus on modifying human activities by education, restricting access to certain sites, and, when access is necessary, deploying and enforcing hygiene procedures to minimise the spread of P. cinnamomi in the landscape.

State government agencies have developed documents detailing hygiene methodologies for work and recreation in and around P. cinnamomi management areas. In addition, the Dieback Working Group (Western Australia) has produced Managing Phytophthora dieback in bushland—a guide for landholders and community conservation groups (2008) and NRM South (Tasmania) has published Keeping it Clean (Allan and Gartenstein, 2010). These methodologies are applicable nationally.

Leave No Trace Australia (www.LNT.org.au) is a national and international minimal impact education program for the recreation, tourism, outdoor education, and land and sea management sectors that focuses on biosecurity as one of its strategic awareness outcomes, including Phytophthora dieback awareness. Working with partners at a state, national, and international level across government, non-government and industry sectors, the Leave No Trace program is delivered as a community and formal education program that seeks to raise awareness of natural and cultural heritage values and the appropriate practices to mitigate the threats to those values.

States have prepared useful approaches for training and awareness-raising directed at reducing the spread of the pathogen. For example:

• The Western Australian Department of Parks and Wildlife (WA DPAW) is introducing a ‘green card’ program and an environmental code of conduct for contractors. Contractors working on-site are given one half day training on environmental threats, including P. cinnamomi and appropriate responses to these threats. This training could be redeveloped for national use to train staff and contractors working in high priority conservation areas, including land management agency staff.

• The Victorian Department of Environment and Primary Industries has a one day workshop, the WeedStop Vehicle Hygiene Program, that can be customised to deal with P. cinnamomi from which participants qualify with a Certificate of Attainment in the nationally accredited unit.

• Regional-scale hygiene methodologies have been developed for the Wet Tropics of North Queensland, where dieback management procedures apply to operational works within the World Heritage Area (Worboys and Gadek, 2004).

The use of the biodegradable, systemic fungicide phosphite to assist existing management strategies has been recommended for protection of susceptible vegetation communities (Aberton et al., 1999; Aberton, 2003). The strategic application of phosphite has been shown to reduce the rate of autonomous spread of the pathogen. Phosphite is examined in more detail below.

Major containment and eradication projects for P. cinnamomi have been undertaken by WA DPAW in both the Fitzgerald River and Cape Arid National Parks in Western Australia.

1.4.2 Mitigating the impact

The tools available for mitigating the impact of P. cinnamomi are limited. The strategic use of phosphonic acids (for example phosphite) and selected fumigants has management potential for impact reduction, containment and eradication of the pathogen. An integrated approach with use of these chemicals, strict access and hygiene controls can successfully mitigate the impact and minimise the spread of the pathogen.

a) Phosphite

The term ‘phosphite’ refers to salts of phosphonic acid (H3PO3). Phosphite treatment induces a strong and rapid defence response in the treated plant. These defence responses stop pathogen spread in a large number of hosts. Phosphite needs to enter a plant’s water transport system in order to be effective. This is achieved by stem injection of phosphite into trees, or spraying phosphite onto the leaves of accessible plants. Injection provides the trees with protection for up to 10 years, while spraying the leaves provides protection for up to one to two years. Efficacy may vary between and within species being treated.

Phosphite has been used to mitigate the impacts of P. cinnamomi on some vulnerable species at infested sites in Western Australia and Victoria. However, phosphite has been found to act as a fertiliser in some circumstances and requires further testing on a greater range of vulnerable species, particularly in other states and territories. Long term phosphite use may have a fertiliser effect in native plant communities occurring on soils with low phosphorous levels resulting in deleterious changes to the plant community (Lambers et al., 2013). The possible deleterious effects of treatment should be included in all monitoring where phosphite is being applied within native plant communities. Further research is required into alternatives to phosphite use.

The Dieback Working Group has produced instruction leaflets on spraying and stem injection of phosphite. These are available on the Dieback Working Group website (http://www.dwg.org.au/).



b) Other impact mitigation methods

A method for eradicating small infestations of P. cinnamomi has been developed and could be applied strategically in suitable areas where priority biodiversity assets occur. The process involves a sequence of treatments: vegetation (host) destruction, fungicide and fumigant treatments, and containment barriers to protect threatened vegetation (Dunstan et al., 2010; Dunne et al., 2011). This method greatly increases the potential for eradicating P. cinnamomi in ecosystems with sandy soils, dominated by root-to-root transmission (refer to the case study in the background document for more detail). Eradication efforts in clay or rocky soils dominated by water associated spread have proven more problematic.

A more recent study by Crone et al. (2012) has shown that, from a management perspective, the above technique may not be successful if annual and herbaceous perennial plant species are allowed to remain. These plants, even without symptoms, may act as hosts of P. cinnamomi. Careful consideration must therefore be made as to the circumstances under which host destruction methods are appropriate.

WA DPAW has developed an assessment of site variables that influence whether eradication or containment of P. cinnamomi is likely (see Appendix E in the background document (Department of the Environment, 2014)).



Ex situ conservation of germplasm in seed banks is a well-established technique used to conserve wild plant genetic diversity and may support the management and conservation of plant species and communities. Guidelines have been prepared for plant germplasm conservation in Australia (ANPC, 2009). By contributing to a project to collect and preserve viable seeds in conservation seed banks in Australia (ASBP, 2013), the Department of the Environment has assisted to build a comprehensive and genetically diverse ex situ collection of native plant taxa that are listed as threatened under the EPBC Act that are at risk from P. cinnamomi.

In situ conservation, or translocation, can also be employed. This is the deliberate transfer of plants or regenerative plant material from one place to another for the purpose of enhancing genetic diversity and habitat for conservation. Guidelines for the translocation of threatened plants in Australia (Vallee et al., 2004) take into account the benefits, risks, planning and implementation associated with the strategy.

Breeding for resistance is another potential impact mitigation method. There is considerable variation in resistance within a species or between species within the same genus or subgenus. Enhancing the process of natural selection for resistance may be a longer term management option for many taxa. Future research may also allow for the transfer of resistance genes into those taxa that at present appear to have no resistance. An improved understanding of the genetic basis of resistance and the genetic diversity of P. cinnamomi will be essential for this work. Initially, the availability of samples of P. cinnamomi cultures, isolated and collected from a wide range of natural ecosystems, would facilitate any research.

More information on the use of phosphite, containment activities and other management measures undertaken in Australia can be found in the background document (Department of the Environment, 2014).

1.5 Climate change

It is difficult to predict how changing climate parameters will impact Phytophthora dieback, but it is likely that the distribution and severity of P. cinnamomi infestations will be significantly altered because of climate change. With predicted average temperature increases of between 1°C and 5°C in Australia by the year 2070 (CSIRO and Bureau of Meteorology 2007-2012), it is probable that Phytophthora dieback will extend into areas (for example, arid and higher altitude regions) that were previously unsuitable for the establishment of the pathogen. In contrast, some areas predicted to have reductions in rainfall could become less conducive to pathogen activity or establishment. The effect of vegetation change on soil temperatures is harder to predict than air temperature changes. This may be a major determinant of the changed distribution of P. cinnamomi in some situations. Recent modelling (CPSM, 2013) will be useful to managers and policy makers involved in ensuring the spread and impact of P. cinnamomi is contained in the future. For a more detailed discussion of the potential interactions between P. cinnamomi and climate change, please refer to the background document (Department of the Environment, 2014).
2. Objectives and Actions

The goal of this TAP is to minimise the impacts of P. cinnamomi on matters of national environmental significance (NES) under the EPBC Act and priority biodiversity assets (that will include matters of NES) identified by the actions of this TAP. To achieve this goal, the TAP has three objectives.

1. Identify and prioritise for protection:

• biodiversity assets

• areas where there is potential for P. cinnamomi to cause native species or ecological communities not yet listed to become eligible for listing under the EPBC Act (in any category, other than conservation dependent).

2. Reduce the spread of P. cinnamomi to, and reduce its impacts on:

• identified priority biodiversity assets

• areas where there is potential for P. cinnamomi to cause native species or ecological communities not yet listed to become eligible for listing under the EPBC Act (in any category, other than conservation dependent).

3. Communicate information about P. cinnamomi, its impacts on biodiversity and actions under this TAP.

Each objective is accompanied by a set of actions which, when implemented, will help achieve the goal of the TAP. Performance indicators have been established for each action. The priorities stated for actions are relative over the life of the TAP. Timeframes listed for the actions are:

short term, 1–3 years

• medium term, 3–5 years

• long term, more than 5 years

• ongoing.

Research actions have been identified that will the support the TAP to achieve its goal. These are listed at the end of this section.

Objective 1: Identify and prioritise for protection biodiversity assets that are, or may be, impacted by Phytophthora cinnamomi

There is a need to determine the risks P. cinnamomi poses to biodiversity assets across Australia and develop a list of national priority biodiversity assets for protection. Attention is drawn to the discussion in the background document on state-based approaches to the assessment of risks from P. cinnamomi.

Appendix A shows EPBC Act listed plant species which may be at risk from P. cinnamomi. Appendix B shows EPBC Act listed threatened ecological communities that may be at risk from P. cinnamomi. Although understanding of plant species’ susceptibility and impacts on dependent wildlife is still developing, these lists provide a starting point for prioritisation.

Threatened species and communities are also listed under state and territory legislation. Australian Government and state/territory lists do not necessarily align, creating the potential for inconsistency in priorities.

Risk assessment methodologies should be the basis for governments in setting management priorities and allocating resources. The risk assessment process extends beyond those susceptible plant species and ecological communities that are currently listed as threatened under the EPBC Act. It also covers those that are at risk of becoming listed due to factors such as proximity to infested areas, and extends to habitat dependent wildlife and plant species that may be impacted by Phytophthora dieback.



Action

Responsible party

Priority

Timeframe

Performance indicators

Action 1.1

Identify species and communities at risk from P. cinnamomi through assessing state/territory and Commonwealth lists of threatened species.



Australian Government and state and territory governments

High priority

Short term

Assessment of threatened species and communities that may be impacted completed and the Threatened Species Scientific Committee advised with 12 months of the making of this TAP.

Gaps and synergies identified to inform management.



Action 1.2

Identify impacts and prioritise flora, fauna and communities at risk to inform P. cinnamomi management.



Australian Government and state and territory governments

High priority

Medium term

Flora and fauna species at risk are identified and prioritised.

Ecological communities at risk are identified and prioritised.

The threat of Phytophthora dieback is evaluated in Commonwealth recovery plans.


Action 1.3

Identify risk areas spatially to generate lists of biodiversity assets at risk from Phytophthora dieback—develop or utilise existing prioritisation frameworks.



Australian Government and state and territory governments

High priority

Medium term

Risk areas identified spatially within three years of the making of this TAP through preparation of:

• maps of potential national distribution of pathogen

• maps of priority biodiversity assets.


Action 1.4

Identify priority biodiversity assets and areas for protection at a local scale—develop or utilise existing prioritisation frameworks.



State, territory and local governments

High priority

Medium term

Revise and produce local scale maps of priority biodiversity assets and protection areas.

Action 1.5

Improve and maintain current monitoring programs.



Australian Government and state and territory governments

Very high priority

Medium term

New infestations in areas of priority biodiversity assets and protection areas are detected and monitored annually.


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