Giles Hardy

Current climate models predict that Western Australia is likely to experience increasing temperatures in the future, which will be coupled with reduced rainfall. This report was commissioned by the Bauxite Hydrology Committee to examine the potential impacts on biodiversity of revegetation practices following bauxite mining due to changes in groundwater connectivity and surface flows that have taken place, and are likely to continue into the future. Particular emphasis was placed on flora and fauna (invertebrate and vertebrate) associated with riparian zones (i.e. the interface between wetter stream zones and upland forests), as effects are likely to be greatest on species within these zones.

Diseases caused by Phytophthora species are responsible worldwide for catastrophic losses in commercial crops and irreparable damage to natural vegetation. Historically, one species (P. infestans) even briefly shaped human migration patterns when it caused famine in Ireland. In Australia, Phytophthora species have also affected horticultural food crops and continue to do so. One species, Phytophthora cinnamomi, is also having a profound effect on natural vegetation in southern Australia, and may well permanently alter the structure, composition and function of some communities, whilst pushing individual species to extinction (Cahill et al. 2008). Recent research has shown that other species of Phytophthora are also having an impact in natural vegetation in Australia. One species (P. ramorum), though not yet present, is known to affect many Australian plants; its airborne dispersal will make it much harder to control than existing Phytophthora species. The aim of this paper is to present information about Phytophthora species that have or potentially have an impact on natural vegetation in Australia and, using P. cinnamomi as a case study, describe current management approaches in two States: Western Australia, where the adverse impact of the disease has been long acknowledged; New South Wales, where the pathogen was thought until recently to be native. We highlight the importance of learning from experience elsewhere to develop the most cost-effective management responses. This will be vital throughout Australia should P. ramorum be introduced into the country.

The assessment of the vulnerability of Australian forests to climate change is an initiative of the Natural Resource Management Ministerial Council (NRMMC). The National Climate Change Adaptation Research Facility (NCCARF) was approached to carry out a comprehensive Forest Vulnerability Assessment (FVA). NCCARF engaged four research groups to investigate distinct aspects in relation to the vulnerability of forests, each of which has produced a report. In addition a fifth group was engaged to create a summary and synthesis report of the project. This report – Biophysical impacts of climate change on Australia's forests - is the second in the series. It presents a review of the primary literature on evidence of impacts of climate change on Australian forests. Existing evidence for climate change impacts in relation to direct stresses (CO2, temperature and rainfall), indirect stresses (fire, pests, pathogens and weeds) and plant processes (growth, transpiration and phenology) is discussed. The report concludes with a discussion of the overall impact of climate change on vegetation and the ecosystem services provided by forests. It should be noted that there have been several excellent reviews of climate change impacts on Australian forests as well as reports on climate change impacts on natural heritage and biodiversity. Conclusions drawn from these earlier reviews are not repeated. Instead, the report focuses on drawing evidence from the primary literature, including grey literature. Relevant literature was identified by bibliographic searches and in consultation with experts across Australia. This review highlighted a number of uncertainties involved in assessing forest vulnerability to climate change. These include uncertainty over changes in the climate, the ecosystem-scale responses to climate change, and interactions of climate change impacts with other global change processes. There is, however, clear evidence of the impact of some individual factors.

Since the 1920’s and possibly earlier, Phytophthora dieback has had, and is continuing to have, a major impact on ecosystem function and health in the South West Botanical Province of Western Australia. Consequently, it is critical that the Department of Environment and Conservation (DEC) and other environmental stakeholders continue to effectively manage Phytophthora dieback to ensure it does not spread into areas free of the disease, or to increase its impact in existing areas of infestation. The Conservation Commission of Western Australia retained the authors to conduct an assessment of Phytophthora dieback management in the State’s terrestrial conservation estate. This includes National Parks, conservation parks, nature reserves, State forests and timber reserves. This was to be done through the analysis of current legislation, regulations, policies and Phytophthora dieback management guidelines that apply to lands vested in the Conservation Commission. This includes the effectiveness of adaptive management procedures that have developed from common sense, experience, research, monitoring and the adjustment of practices based on what has been learnt. The analysis was to be evidence based, to include interviews with personnel involved with Phytophthora dieback and to include specific case studies (Fitzgerald River, Lesueur, Stirling Ranges and Wellington National Parks, with Alcoa Australia Ltd. included as an industry based case study). The case studies were to be used to determine the effectiveness of Phytophthora dieback management. The study was to indicate the strengths and weakness of current management and to make recommendations for further improvement based on the interviews and reviews of the existing legislative and Phytophthora management guidelines.

The area of Australian native vegetation in temperate and tropical Australia affected by Phytophthora cinnamomi exceeds many hundreds of thousands of hectares, and continues to increase. In Western Australia alone, greater than 6000 km2 are now infested and 41% of the approximately 6000 plant species in the South West Botanical Province are susceptible. P. cinnamomi and the disease caused by it is a ‘key threatening process to Australia’s Biodiversity’. While the pathogen is widespread and large areas are now infested, many areas of high conservation value remain free of the pathogen. Pathogen free areas could remain so, given effective hygiene and quarantine measures are applied, and if effective methods can be developed to eliminate incursions of the pathogen. To date, there are no robust methods available to eradicate P. cinnamomi from spot infestations or to contain the spread of the pathogen along an active disease front. The need to eradicate or contain the pathogen is now paramount to ensure threatened flora or threatened ecological communities are protected for the long-term. The aim of this study was to develop protocols that can be used to contain and eradicate spot infestations of P. cinnamomi that, if untreated, are likely to threaten extensive areas of native vegetation or areas of high conservation value. Treatment regimes were guided by two assumptions: 1) within the selected sites transmission of the pathogen is by root-to-root contact; and 2) the pathogen is a weakly competitive saprotroph. In Cape Riche, Western Australia, treatment and control plots were set up along an active disease front within scrub-heath vegetation dominated by Banksia spp. Treatments applied sequentially and in combination, included: 1) destruction of the largest plants within disease free vegetation forward of the disease front; 2) destruction of all plants to create a fallow or ‘dead zone’; 3) installation of physical root barriers and subsurface irrigation for the application of fungicide/s; 4) surface applications of fungicides selective against Oomycetes (triadiazole and Metalaxyl-M) and; 5) surface injection and deep (± 1 m) treatments with the soil fumigant methamsodium. In a separate experiment in Narawntapu National Park (NP), Tasmania, two treatment regimes were applied to experimental heath plots with active disease centres within a Eucalyptus-Banksia woodland. Treatments were: 1) a combined treatment including vegetation removal, Metalaxyl-M and metham-sodium and root barriers and; 2) with Metalaxyl-M and root barriers alone. Standard baiting techniques were used to recover P. cinnamomi from combined soil and root samples, down to 1.5 m deep at Cape Riche, and to 1 m at Narawntapu NP. Research into natural and induced resistance in Australian native vegetation of Phytophthora cinnamomi and innovative methods to contain and/or eradicate within localised incursions in areas of high biodiversity in Australia.

To test the efficacy of treatments against a pathogen it is necessary to have a standard pathosystem. We assessed the suitability of intact Arabidopsis plants from 20 ecotypes, root inoculated with 29 P. cinnamomi isolates, as Arabidopsis offers so many advantages for physiological and molecular work and allows fast throughput of trials. It was shown that intact Arabidopsis plants, grown hydroponically and root inoculated with P. cinnamomi zoospores are not a suitable pathosystem, as although root mass is reduced, shoots are qualitatively and quantitatively unaffected and plants remain healthy. An ideal pathosystem is one where susceptible Arabidopsis ecotypes die and resistant Arabidopsis ecotypes survive. Detached leaves of 4-week old Arabidopsis (ecotype Landsberg erecta) plants inoculated with zoospores or mycelium of P. cinnamomi provided a good model system for some of the analysis of the effects of phosphite as infection could be assessed through lesion size and abundance of callose papillae. Leaves treated with phosphite showed reduced lesion size and increased numbers of callose papillae. Using qPCR an increase in the level of expression of the defense gene PRI was quantified. Although not an ideal pathosystem, Arabidopsis can be used to examine very early defense responses (in the first few days following inoculation) after treatment with phosphite. A rapid assay was developed to compare the effect of phosphite and metabolic inhibitors on pathogenicity of P. cinnamomi. Filter paper discs overgrown with P. cinnamomi were treated with 20 μL drops of phosphite or inhibitors, then tested for pathogenicity (ability to colonise lupin roots), or growth on NARPH plates. It was shown that c-AMP is likely to be involved in the reduction by phosphite of P. cinnamomi pathogenicity. The technique provides a means of screening compounds that might enhance phosphite efficacy, and to explain the mode of action of phosphite. Quantification of phosphite uptake and movement in the plant is hampered by the lack of a quick, cheap method of measuring accurately the concentration of phosphite in different plant tissues. Costs of the existing HPLC method (~$30 per sample) prevent such studies, and analyses in the region of $1 - $5 per sample are required. We examined two methods (a silver nitrate assay, and a phosphite dehydrogenase assay) as potential methods of accurately and cost effectively measuring phosphite in plant tissues. Both methods proved promising and represent exciting advances in phosphite analysis. Some additional fine tuning is required to ensure that the methods are reliable across a range of plant species from different families. A cheap, accurate and robust analytical method will allow many important questions about phosphite uptake and movement to be investigated.

Phosphite is of major importance in controlling root disease caused by Phytophthora cinnamomi. It acts both directly and indirectly on the pathogen. In order to maximise the efficacy of phosphite we need to understand how the physiological status of the plant at the time of phosphite application affects control. The physiological status of plants is not constant but varies over time depending on developmental gene expression (e.g. leaf phenology, flowering/fruiting and senescence) and interactions with the environment (e.g. temperature, moisture, light, fire, nutrients and other biota). In Mediterranean environments in particular, plants experience stresses due to extremes in water availability and the incidence of wild fire is high. Furthermore, individuals and species of plants are not in synchrony due to differences in recruitment, ontogeny, longevity and rest periods. Therefore, from a management perspective when considering all of these stresses native plant communities are subjected to, it is critical to know when to apply phosphite to ensure optimal disease control. We examined each of the key environmental stresses (water excess, water deficit, fire and flowering) independently, on the efficacy of phosphite to control disease.

Disease in natural ecosystems of Australia, caused by the introduced plant pathogen Phytophthora cinnamomi, is listed as a key threatening process under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act). The Act requires the Australian Government to prepare and implement a threat abatement plan for nationally coordinated action to mitigate the harm caused by P. cinnamomi to Australian species, particularly threatened flora, fauna and ecological communities. The .National Threat Abatement Plan for Dieback Caused by the Root-Rot Fungus Phytophthora cinnamomi. (NTAP) was released in 2001 (Environment Australia, 2001). The NTAP is designed to promote a common understanding of the national threat P. cinnamomi poses to biodiversity in Australia. This project, funded by the Australian Government Department of the Environment and Heritage (DEH), is one of the most significant actions to be implemented from the NTAP to date. The project has two major components: * to review current management approaches and identify benchmarks for best practice * the development of risk assessment criteria and a system for prioritising management of assets that are or could be threatened by P. cinnamomi. The project outputs are presented in a four-part document entitled Management of Phytophthora cinnamomi for Biodiversity Conservation in Australia: Part 1 - A Review of Current Management Part 2 - National Best Practice Guidelines Part 3 - Risk Assessment for Threats to Ecosystems, Species and Communities: A Review Part 4 - Risk Assessment Models for Species, Ecological Communities and Areas. A model of best practice was developed which encompasses all the components necessary for an informed and integrated approach to P. cinnamomi management, from strategic through to on-ground management. The current document (Part 1 . A Review of Current Management) thoroughly reviews the approaches to P. cinnamomi management in Australia within the context of the best practice model.

Disease in natural ecosystems of Australia, caused by the introduced plant pathogen Phytophthora cinnamomi, is listed as a key threatening process under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act). The Act requires the Australian Government to prepare and implement a threat abatement plan for nationally coordinated action to mitigate the harm caused by P. cinnamomi to Australian species, particularly threatened flora, fauna and ecological communities. The .National Threat Abatement Plan for Dieback Caused by the Root-Rot Fungus Phytophthora cinnamomi. (NTAP) was released in 2001 (Environment Australia, 2001). The NTAP is designed to promote a common understanding of the national threat P. cinnamomi poses to biodiversity in Australia. This project, funded by the Australian Government Department of the Environment and Heritage (DEH), is one of the most significant actions to be implemented from the NTAP to date. The project has two major components: * to review current management approaches and identify benchmarks for best practice * the development of risk assessment criteria and a system for prioritising management of assets that are or could be threatened by P. cinnamomi. The project outputs are presented in a four-part document entitled Management of Phytophthora cinnamomi for Biodiversity Conservation in Australia: Part 1 - A Review of Current Management Part 2 - National Best Practice Guidelines Part 3 - Risk Assessment for Threats to Ecosystems, Species and Communities: A Review Part 4 - Risk Assessment Models for Species, Ecological Communities and Areas. A model of best practice was developed which encompasses all the components necessary for an informed and integrated approach to P. cinnamomi management, from strategic through to on-ground management. The current document (Part 1 . A Review of Current Management) thoroughly reviews the approaches to P. cinnamomi management in Australia within the context of the best practice model.

Tree declines are now a common phenomenon across a wide range of eucalypt species throughout Australia. There is considerable concern about the rate of spread and intensity of these declines and the subsequent impact they are having on ecosystem function and health. In Western Australia the most prominent declines occurin Eucalyptus gomphocephala (tuart) and Eucalyptus wandoo (wandoo), although E. loxophleba (York gum), E. marginata (jarrah), E. rudis (river gum), E. salmonophloia (salmon gum) and Corymbia calophylla (marri) are also impacted upon. Most of these tree declines appear to be due to complex interactions of biotic and abiotic factors with no single cause. These include: (i) habitat loss and fragmentation, (ii) changes in land management, e.g. fire management, forestry practices, (iii) changes in hydrology, (iv) pests and pathogens and (v) climate change. In order to bring about the effective mitigation and management of these declines it is critical to conduct well planned and integrated research across a range of scientific disciplines. Without a coordinated approach, research activities will be ad hoc and short term.