Nature conservation

Threatened species

Infection of native plants by Phytophthora cinnamomi



Description

*****NOTE: THIS IS A DRAFT STRATEGY***** Phytophthora cinnamomi was probably introduced to Australia soon after European human settlement. Since the mid-1960s, it has been increasingly recognised as a serious threat to many native plants and ecosystems. P. cinnamomi is widespread in NSW, particularly in higher rainfall areas (>600 mm annually), although it has been reported in Western Australia areas with average yearly rainfall as low as 400 mm. The most favourable conditions for spore production are free water and warm temperatures. The development of the disease, Phytophthora dieback, requires multiple factors that must operate together. 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. 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 - thus, symptoms of P. cinnamomi infection have similarities 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. P. cinnamomi can be spread in water, soil or within plant material that contains the pathogen, and dispersal is favoured by moist or wet conditions. It can be carried in both overland and sub-surface 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 associated 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 because of human activity, often as a direct result of the introduction of infested soil or road-building materials to vulnerable non-infested areas. This disease is often difficult to detect and can cause significant and permanent damage to ecosystems before detection. 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; and • habitat loss and degradation for dependent flora and fauna. To date these have been irreversible.

Biodiversity values impacted

The extent of P. cinnamomi impact within NSW is generally unknown. It does not appear to be causing the dramatic widespread vegetation loss that has been observed in other southern Australian states. However, the pathogen is having a significant local impact on native vegetation in several widely spaced parts of eastern NSW, and these impacts are primarily on understorey plant species. Susceptible threatened plant species listed under the Biodiversity Conservation Act 2016 include: Wollemia nobilis (Wollemi Pine), Leionema ralstonii (Ralston’s Leionema) and Tasmannia purpurascens (Broad-leaved Pepperbush). A further 78 rare or threatened species are thought to be at risk from the pathogen due to their proximity to known infestations or their occurrence in vulnerable habitats. This includes fauna such as the smoky mouse (Pseudomys fumeus) and southern brown bandicoot (Isoodon obesulus) that occupy heathy-type habitats with susceptible plant species that afford vital shelter and/or food. Evidence of P. cinnamomi-induced dieback has been identified in the following vegetation classes: • Montane wet sclerophyll forest • North Coast wet sclerophyll forests • Northern escarpment dry sclerophyll forest • Southern lowland wet sclerophyll forests • South Coast sands dry sclerophyll forests • South Coast heaths • South-east dry sclerophyll forests • Subalpine woodlands • Sydney coastal dry sclerophyll forests • Wallum sand heaths

Strategy objective

• Minimise the spread of P. cinnamomi, thereby preventing impacts on new species and ecological communities; • Reduce the impacts of P. cinnamomi on susceptible species and ecological communities in locations currently known to be affected; • Improve understanding of the distribution and movement of P. cinnamomi within NSW; • Raise awareness and understanding of the impacts and risks of spread of P. cinnamomi, among land managers and other relevant stakeholders in NSW.

Priority actions for this KTP

Research

Action DescriptionScale
Investigate the feasibility and efficacy of sterilising road building and maintenance materials (e.g. treating road base / gravel with metham sodium) or sourcing certified virgin excavated natural material for reducing spread of P. cinnamomi.Site
Investigate the applicability and efficacy of ecological restoration as a tool to mitigate P. cinnamomi impacts on particular vegetation communities. Include investigation of genetic resistance to P. cinnamomi in potentially susceptible species and how this may be applied to assist restoration efforts.Site
Investigate the efficacy of phosphonate on treating P. cinnamomi infection in susceptible species and ecological communities, in terms of reducing spread within affected communities. Improve understanding of relative efficacy for different species and application methods.Site
Test to determine the susceptibility of flora that occur in high risk areas (identified via risk map). Threatened species should be prioritised, as should widespread species that occur within the P. cinnamomi environmental envelope or those that could be informative to modelling risk. Integrate susceptibility testing into routine germination trials associated with seed banking (liaise with Royal Botanic Gardens and Australian National Botanic Gardens).State
Prepare a P. cinnamomi risk map for eastern NSW to identify areas where there are environmental conditions conducive to the establishment and persistence of P. cinnamomi and species that are susceptible or likely to be susceptible. Begin by collating existing maps/data sets (e.g. Royal National Park, Greater Blue Mountains World Heritage Area, Gondwana World Heritage Area). Mapping should incorporate predicted dynamics for risk to species and locations in the future under climate change. Data gaps should be addressed with targeted surveys and soil sampling in susceptible areas.State
Investigate relative importance of different dispersal vectors (e.g. cars, walkers, horses, cyclists, feral animals, road construction/maintenance) in spreading P. cinnamomi around the landscape.Area
Investigate the relative effectiveness of available hygiene measures (e.g. footbaths, boot scrubbing stations, wash down facilities), with consideration of the comparative importance of different factors explaining efficacy – technical (e.g. soil removal, utility of disinfectants) and social (e.g. usage of hygiene equipment) – as well as relative cost.Site

Prevention

Action DescriptionScale
No critical actions have been identified under a prevention response as P. cinnamomi is already present in NSW.State

Containment

Action DescriptionScale
In priority locations with high foot traffic, install signage (e.g. ‘Stay on marked tracks’) to reduce off-track disturbance and elevate or divert walking tracks to minimise contact with soil, particularly in locations that have the potential to become muddy.Site
Install disinfecting facilities – wash-down bays, footbaths and/or scrubbing stations, as appropriate dependent on conditions – at primary entrance/exit points for vehicles and foot traffic, in priority locations (e.g. reserves with known P. cinnamomi infestation and/or susceptible species).Site
If P. cinnamomi is detected where susceptible threatened or keystone species occur, apply phosphonate strategically (and where known not to have phytotoxic effects) to slow the spread.Site

Strategic

Action DescriptionScale
Develop a database to compile data on the distribution and impacts of P. cinnamomi infection across NSW. Develop supporting data collection protocols based on those used in Western Australia. Encourage all stakeholders collecting soil samples to follow these protocols and contribute to the database.State
Implement a regime of regular soil sampling at strategic locations (identified via decision-support tool) to track spread of P. cinnamomi across the landscape within NSW.State
Develop a nomination for the NSW Scientific Committee to amend the current KTP determination to include other relevant soil-borne Phytophthora species.State
Liaise with relevant regulatory authorities (i.e. APVMA and Commonwealth Department of the Environment) to obtain a permit for broad scale application of phosphonate (i.e. > 1 ha/year).State
Develop a decision-support tool to identify and prioritise sites for investment in management and monitoring of P. cinnamomi. The tool should be informed by a risk map (see Research Actions), and incorporate factors associated with key vectors (see Research Actions), value of susceptible biodiversity (e.g. scarcity, ecological function), topography, hydrology and feasibility of management.State
Develop and implement a communications strategy to raise awareness of the risks, impacts and vectors of P. cinnamomi, separately targeting: • Land managers and practitioners (e.g. environmental agency staff, contractors, researchers, volunteers) – should be based on phytosanitary guidelines and could include elements such as workshops, training sessions and/or a certification approach like the ‘Green Card’ system implemented in Western Australia • General public – should target bushwalkers, horse-riders and other recreational users of public land. See Western Australia’s ‘Project Dieback’ online and printed communications materials for reference.State
Prepare a phytosanitary protocols and guidelines document to educate and enable relevant land managers to reduce risk of spreading P. cinnamomi.State
Liaise with key land management organisations (e.g. National Parks and Wildlife Service, Forestry Corporation NSW, LLS, local governments) to encourage the establishment and use of vehicle wash-down stations in areas with susceptible and high value biodiversity.Area

Distribution of the KTP in NSW

Biodiversity asset protection

The table below outlines the threatened species or ecological community strategies that identify actions to manage the threat of P. cinnamomi at a priority SoS site. The table is not a comprehensive list of all species or sites impacted by the threat in NSW.

Species scientific nameSpecies common nameSite name
Acacia terminalis subsp. terminalis Sunshine Wattle Northern Beaches
Baeckea kandos Baeckea kandos Dunns Swamp
Banksia conferta subsp. conferta Banksia conferta subsp. conferta Coorabakh National Park
Banksia vincentia Banksia vincentia Vincentia
Ben Halls Gap Nature Reserve Sphagnum Moss Cool Temperate Rainforest Ben Halls Gap Nature Reserve Sphagnum Moss Cool Temperate Rainforest Ben Halls Gap Nature Reserve
Blue Gum High Forest in the Sydney Basin Bioregion Blue Gum High Forest in the Sydney Basin Bioregion Hornsby Diatreme
Commersonia prostrata Dwarf Kerrawang Tomago area
Darwinia peduncularis Darwinia peduncularis Berowra - Lane Cove
Dracophyllum macranthum Dracophyllum macranthum Coorabakh
Duffys Forest Ecological Community in the Sydney Basin Bioregion Duffys Forest Ecological Community in the Sydney Basin Bioregion Duffys Forest
Duffys Forest Ecological Community in the Sydney Basin Bioregion Duffys Forest Ecological Community in the Sydney Basin Bioregion Hornsby
Duffys Forest Ecological Community in the Sydney Basin Bioregion Duffys Forest Ecological Community in the Sydney Basin Bioregion Ingleside_Terrey Hills
Elderslie Banksia Scrub Forest Elderslie Banksia Scrub Forest Spring Farm
Eucalyptus camfieldii Camfield's Stringybark North Head, Sydney Harbour
Eucalyptus glaucina Slaty Red Gum Braemar
Eucalyptus glaucina Slaty Red Gum Minimbah
Genowlan Point Allocasuarina nana Heathland Genowlan Point Allocasuarina nana Heathland Mugii Murum-ban State Conservation Area
Grevillea molyneuxii Wingello Grevillea Morton National Park
Grevillea parviflora subsp. supplicans Grevillea parviflora subsp. supplicans Marramarra
Grevillea renwickiana Nerriga Grevillea Morton National Park
Grevillea shiressii Grevillea shiressii Lower Mooney Mooney Creek
Hakea archaeoides Big Nellie Hakea Coorabakh
Isopogon fletcheri Fletcher's Drumsticks Rigby Hill
Leionema ralstonii Ralston's Leionema Jingera rock (site no. 12)
Leionema ralstonii Ralston's Leionema Rocky outcrop no. 25
Leionema ralstonii Ralston's Leionema Rocky outcrop no. 3
Prostanthera junonis Somersby Mintbush Reeves Road
Prostanthera junonis Somersby Mintbush Reservoir Road
Prostanthera marifolia Seaforth Mintbush Manly Dam
Prostanthera palustris Swamp Mint-bush Bundjalung National Park
Prostanthera staurophylla sensu stricto Prostanthera staurophylla sensu stricto Mount Mackenzie
Prostanthera stricta Mount Vincent Mint-bush Genowlan Mountain
Pseudomys fumeus Smoky Mouse Nullica
Pultenaea baeuerlenii Budawangs Bush-pea Corang Trig
Pultenaea parrisiae Parris' Bush-pea Imlay Road
Pultenaea parrisiae Parris' Bush-pea Wadbilliga National Park
Pultenaea sp. Genowlan Point Pultenaea sp. Genowlan Point Genowlan Point
Tasmannia glaucifolia Fragrant Pepperbush Barrington Tops
Westringia davidii David's Westringia Rocky outcrop no. 25
Westringia davidii David's Westringia Rocky outcrop no. 3
Wollemia nobilis Wollemi Pine Wollemi National Park
Zieria covenyi Coveny's Zieria Breakfast Creek
Zieria lasiocaulis Willi Willi Zieria Willi Willi National Park
Zieria murphyi Velvet Zieria Morton National Park

Investment prioritisation

Priorities for investment in particular projects under SoS will be determined based on alignment with the critical actions outlined above, as well as their benefit (in terms of meeting SoS objectives) relative to implementation cost, as per the SoS KTP Framework.

Monitoring and evaluation

No monitoring and evaluation information available.

Interaction with other KTPs

Key Threatening ProcessInteraction and impacts
Anthropogenic Climate ChangeChanges to rainfall patterns and temperatures are likely to affect site suitability for P. cinnamomi, and therefore its distribution in NSW.
Clearing of native vegetationClearing and disturbance of vegetation is likely to disturb soil and increase risk of P. cinnamomi spreading.
Predation, habitat degradation, competition and disease transmission by Feral Pigs, Sus scrofa Linnaeus 1758Vertebrate pests are likely to be important vectors transporting P. cinnamomi spores through the landscape and spreading infection.
Competition and grazing by the feral European Rabbit, Oryctolagus cuniculus (L.)Vertebrate pests are likely to be important vectors transporting P. cinnamomi spores through the landscape and spreading infection.
High frequency fire resulting in the disruption of life cycle processes in plants and animals and loss of vegetation structure and compositionFire disrupts surface and sub-surface water flow via changes to vegetation structure, which affects spread of P. cinnamomi. Also, fire management such as mechanical installation of control lines disturbs soil and increases risk of P. cinnamomi spread.
Removal of dead wood and dead treesVehicles involved with removal of timber are likely to disturb soil and act as vector for P. cinnamomi
Predation by the European Red Fox Vulpes Vulpes (Linnaeus, 1758)Loss of vegetative cover as a result of P. cinnamomi infection increases the risk of predation by foxes.
Predation by the Feral Cat Felis catus (Linnaeus, 1758)Loss of vegetative cover as a result of P. cinnamomi infection increases the risk of predation by feral cats.
Invasion and establishment of exotic vines and scramblersPhytophthora could be introduced to or spread from sites while carrying out control of exotic vines and scramblers. Hygiene actions to reduce spread of Phytophthora should be incorporated into any on ground works in high risk areas.
Loss and degradation of native plant and animal habitat by invasion of escaped garden plants, including aquatic plantsPhytophthora could be introduced to or spread from sites while carrying out control of garden escapes. Hygiene actions to reduce spread of Phytophthora should be incorporated into any on ground works in high risk areas.
Invasion and establishment of Scotch Broom (Cytisus scoparius)Phytophthora could be introduced to or spread from sites while carrying out Scotch Broom control. Hygiene actions to reduce spread of Phytophthora should be incorporated into on ground works in high risk areas.
Invasion of native plant communities by exotic perennial grassesPhytophthora could be introduced to or spread from sites while carrying out control of exotic perennial grasses. Hygiene actions to reduce spread of Phytophthora should be incorporated into any on ground works in high risk areas.
Invasion, establishment and spread of Lantana (Lantana camara L. sens. Lat)Phytophthora could be introduced to or spread from sites while carrying out lantana control. Hygiene actions to reduce spread of Phytophthora should be incorporated into any on ground works in high risk areas.
Invasion of native plant communities by African Olive Olea europaea subsp. cuspidata (Wall. ex G. Don) Cif.Phytophthora could be introduced to or spread from sites while carrying out control of African olive. Hygiene actions to reduce spread of Phytophthora should be incorporated into any on ground works in high risk areas.
Invasion of native plant communities by Chrysanthemoides moniliferaPhytophthora could be introduced to or spread from sites while carrying out control. Hygiene actions to reduce spread of Phytophthora should be incorporated into any on ground works in high risk areas.

How will this species be managed?

Key management sites for this threatened species are being identified by the Office of Environment and Heritage and other program partners, where feasible, cost-effective and beneficial to the threatened species. Currently, no management sites have been identified for this threatened species.

  • Develop a phytosanitary protocol and guideline document for the management of Phytophthora, focussing on minimising pathogen spread where the pathogen is present and preventing pathogen introduction where it is absent. Provide document to all land managers throughout NSW, including environmental agency staff, contractors, researchers and volunteers.
  • Develop a Phytophthora cinnamomi risk map for NSW using spatial layers of P. cinnamomi presence and absence, biodiversity assets and climate.
  • Assess the effectiveness of hygiene measures (e.g. footbaths, boot scrubbing stations, wash down facilities, disinfectants) by collecting soil samples from locations with and without these measures and testing for Phytophthora cinnamomi. Also conduct hygiene trials under controlled conditions.
  • Conduct tests under greenhouse conditions to assess the disease susceptibility of 30-40 threatened NSW plants. Determine the efficacy of phosphonate treatments for plants found to be highly susceptible to Phytophthora cinnamomi.