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The reintroduction of Growling Grass Frogs to Winton Wetlands

The Growling Grass Frog (GGF) was last recorded at Winton Wetlands in 1970.  It is likely that the construction of the Lake Mokoan Dam and the inundation of the wetlands led to the extinction of the species within Winton Wetlands. The decommissioning of the dam has seen the ongoing restoration of the landscape’s hydrology, and the revival of the ephemeral nature of the wetlands. As it stands, the wetlands once again can provide suitable habitat for the GGF. By reintroducing GGF to the Winton Wetlands we hope to increase the number of wild populations of the GGF in Victoria and the species area of occurrence Nationally. Other known GGF populations are beyond the natural dispersal distance of the GGF and so the species is not able to naturally recolonize the Winton Wetlands site.

This project supports the Winton Wetlands Restoration and Monitoring Plan as it acts to ‘restore ecosystem function’ through an increase in the diversity of native fauna.  The reintroduction of this ecologically important frog species will act to further stabilise the aquatic and terrestrial ecosystem through the addition of an important predator and prey species.  We expect that the reintroduction of an ecologically distinct frog species will improve the systems’ resilience and long-term viability.

This project supports the Biodiversity 2037 policy of the Victorian Govt in its efforts to promote the collection of targeted data for evidence-based decision-making, increase opportunities for all Victorians to act to protect biodiversity, and adopt a collaborative biodiversity response planning approach to drive accountability and measurable improvement. It also addresses the local concerns on the current condition of Victoria’s biodiversity. The strong scientific underpinning of this project is the key to supporting the species recovery in the long term and forms a key focus of this project. This project also supports actions within the Goulburn-Broken and North-East Catchment Management Strategy both for 2013-2019 and in the new draft strategy to support threatened species and to increase participation opportunities for communities to engage with their natural environments.

Recently, the GGF was named as one of the 100 priority species listed by the Department of Agriculture, Water and the Environment to help focus the efforts of the Australian Government and partners on threatened species recovery actions. This program aims to improve the trajectories of priority threatened species by 2031. Recovery actions for many of the priority species will also benefit other threatened species that share their habitat.

Stage 1- GGF Reintroduction Feasibility Study

In 2017/2018, a study was carried out that aimed to explore the feasibility of a reintroduction of GGF onto the wetland through the measurement, monitoring and reporting of:

  • Habitat characteristics of the release site (aquatic and terrestrial vegetation extent, type, water depth, salinity and temperature)
  • Chytrid fungus presence and prevalence on other frogs in the reserve
  • Frog call recording and frog surveys to confirm the absence of GGF from the site

 

This study was financially supported by the Wettehnall Environment Trust, with significant research support provided by Dr Geoff Heard.

After data was collected on site, a population viability analyses was conducted by Dr Geoff Heard.  His analyses indicates that habitat at the Winton Wetlands could support a viable GGF population and that Winton Wetlands is therefore a suitable location for a GGF translocation. The study showed that:

  • the habitat is suitable with a network of permanent and ephemeral wetlands vegetated and open water areas, as well as having several basking areas (rock) in the margin of some wetlands.
  • the water quality (salinity) and temperature ranges are suitable for GGFs and equivalent to sites supporting GGF elsewhere
  • low chytrid loads on existing frogs
  • few other predators and a control program in place to keep carp populations low
Stage 2- Captive breeding and quarantine facility preparation

After the results of the feasibility study, we successfully secured financial support from Wettenhall Environment Trust and the Ross Trust for ‘Stage 2’ of the project, which involved the design and construction of the facilities to house and breed frogs and the preparation of permits required for the translocation of GGFs to Winton Wetlands.

The funding provided has allowed us to construct both a quarantine laboratory facility and outdoor captive breeding facility onsite, adjacent to the current Education Centre building.  This will allow for the translocation, quarantine and breeding of GGFs at Winton Wetlands.

The funding has also supported our efforts to prepare and secure many of the relevant permits required to translocate, breed and release frogs at Winton Wetlands.  These permits included:

  • A Scientific Procedures Premises Licence for the quarantine and captive breeding facility (Animal Welfare Victoria)
  • An animal ethics permit (via the Wildlife and Small Institutions Animal Ethics Committee)
  • Support for our Translocation plan via the Translocation Evaluation Panel
  • A Wildlife Research Permit through the Department of Environment, Land, Water and Planning

As soon as our federal permissions are in place (pending), we are set to translocate frogs back to the site.

CLICK HERE for Information sheet on Stage 2 of Growling Grass Frogs Rewilding project, April 2021

Stage 3- Growler Translocation and Taskforce Growler launch (scaling up the impact of the reintroduction)

We’ve finally reached the most exciting phase of this work, which involves the launch of ‘Taskforce Growler’ and the physical translocation of Growling Grass Frogs to Winton Wetlands (due in Summer 2023, after permit finalisation).

This stage of the work (generously supported by the GBCMA and MDBA) aims to promote and advocate for the conservation of GGFs both at Winton Wetlands and more broadly across Northern Victoria.

The ‘Taskforce Growler’ initiative offers stakeholders, scientists, land managers and the general public the opportunity to become part of a taskforce that directly assists GGF conservation via:

  • Participation in a facilitated ‘GGF practitioners network’ that regularly shares knowledge and research (virtual and in person) on everything and anything related to Growling Grass Frog conservation
  • Assisting with Growling Grass Frog husbandry (feeding, weighing and measurements of frogs in the quarantine and captive breeding facility). Training will be provided for those interested.
  • ‘Growing Grub For Growlers’- Grow food for our captive population- we need a steady supply of greens (endive, lettuce etc) for tadpoles and colonies of wood roaches or crickets for adults in captivity
  • Recording potential GGF calls on the Frog ID app
  • Identifying, recording and protecting habitat for GGFs within GBCMA and northern Victoria
  • Advocating for the species and the project
  • Donation of funds that are put directly toward:
    • the captive breeding and husbandry of GGFs at Winton Wetlands
    • genetic and chytrid sampling and analyses of frogs from other Northern Victorian populations of GGFs
    • Taskforce Growler project co-ordination and management (i.e. support of a Project Officer type of role)

Photos : Lisa Cox, Winton Wetlands staff