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Fire and Rust

Assessing the impact of Myrtle rust on fire regeneration

Background
While fire is considered an important selection agent in the development of Australia’s native flora, the development of new epicormic regrowth and young seedlings en-masse after fire are ideal for the development and spread of the rust fungus Myrtle rust (Austropuccinia psidii). Recent extreme fire events have resulted in significant impacts on a range of different ecosystems, with widespread epicormic and seedling regeneration now occurring, creating ideal conditions for the spread and impact of rust.

Aims
This project, funded by the Threatened Species Recovery Hub, aims to determine the susceptibility and impact of myrtle rust on Myrtaceae species regenerating after the 2019-20 wildfires. Locations across fire affected regions in NSW and Queensland will be targeted with general surveys to capture data across a range of sites and species. Short term impact assessment plots will be established at selected sites and data recorded on disease progression/species decline rates on a monthly basis. The project will identify the species showing susceptibility and the regeneration forms (re-shoots/seedlings) affected by Myrtle rust. The effect of repeated infection on species recovery/survival will be determined for species highlighted in priority lists, including bushfire affected threatened plants.

In cooperation with the Department of Agriculture & Fisheries Queensland, the NSW Department of Primary Industries, the University of New South Wales, Queensland University of Technology, and technicians and botanists drawn from the private sector, surveys will be conducted across a wide range of ecosystems to capture information on species susceptibility. Surveys are being conducted over six months in 2020 during the peak periods for Myrtle rust activity. Data will be collected on a range of species of known susceptibility and locations where Myrtle rust is likely to be most damaging, with a steering committee formed to further advise on sites and species of significance worst affected by fire. Monitoring plots will be established or recommended based on survey results, focussing on species identified as likely to be at higher risk, to assess the impact of repeated infection of Myrtle rust on post-fire plant regeneration. Preliminary surveys suggest species not normally seen as susceptible in undisturbed sites are becoming infected and impacted by Myrtle rust.

The research is taking place across a number of sites and ecological communities in Queensland and New South Wales:

  • reserves within the Gondwana Rainforests of Australia World Heritage property (Lamington and Main Range National Park, Washpool and Gibraltar National Park)
  • sites in both states featuring the Lowland Rainforest of Subtropical Australia Threatened Ecological Community
  • coastal heath and woodland environments in New South Wales and Queensland (Bundjalung and Cooloola/Noosa National Parks/K’gari (Fraser Island))
  • environments on the south coast of New South Wales affected by fire.

During the surveys, we will record impacts on reshoots and seedlings of a range of species. Additional site data collected will include fire severity, vegetation type and species composition. Where possible, species present across these different environments will be targeted (e.g., Melaleuca nodosa, M. quinquenervia, Eucalyptus pilularis).Disease incidence and severity data will be collected for a range of species and locations where rust is likely to be most damaging. To assist with species conservation and/or restoration planning, data on species populations and/or individuals free of disease and possibly resistant to myrtle rust will also be captured.

In-field Myrtle rust identification and assessment training workshops will also be provided to regional Parks and Wildlife staff, landowners and land care groups, to assist in expanding the capacity to report on Myrtle rust impacts.

The ANPC would like to thank the Threatened Species Recovery Hub for this funding.

All photos on this page provided by Geoff Pegg.