Images courtesy of WWF Australia.
The Grey-headed Flying-Fox (GHFF) is a native Australian species and is listed as vulnerable in Victoria and nationally. GHFF play a critical role in maintaining the health of our forests and ecosystems through long-distance pollination and seed dispersal. Endemic to the forests of south-eastern Australia, a colony GHFF settled at Rosalind Park in Bendigo, Victoria in 2010. The number of flying-foxes at Rosalind Park varies seasonally and annually, with between 2000 and 30,000 calling Bendigo home at any one time.
Our client, the City of Greater Bendigo, requested WSP’s assistance to undertake a trial to assist in the planning, design, installation and evaluation of both an artificial roost and an atmospheric cooling system for the GHFF roosting in Rosalind Park.
A key collaboration in this project was the bringing together of Council and the World Wide Fund for Nature (WWF) who contributed funds under the climate resilience program.
The aim of the trial is to:
- Protect and enhance canopy cover, tree health and tree survival, especially within the fernery
- Improve animal welfare outcomes
- Reduce the need for and extent of human intervention during extreme heat events
- Identify and test alternative roosting approaches
- Identify and test approaches to cool the atmosphere on extreme heat days
- Undertake a scientifically robust evaluation and report to enable evidence-based decisions by Council and other camp managers facing similar challenges across Australia
Artificial roosting in Rosalind Park
Located in the centre of Bendigo, Rosalind Park is a significant site for its historic trees where many date back to the 1800s.
The GHFF affect the tree branches they are roosting on through damage from their claws and breakage due to their combined weight. Consequently, many trees in the park are showing varying levels of damage, with the most affected in the fernery area.
Acknowledging the level of damage was reducing the useful life expectancy and survival rate of the trees, the City of Greater Bendigo (Council) are investigating and trialling artificial roosting structures within the fernery of Rosalind Park to relieve pressure on the trees and improve tree health.
Atmospheric cooling systems for GHFF
The Council are also trialling an atmospheric cooling system of sprinklers within the tree canopy to cool the bats, restore humidity in the fernery and protect the mid-storey plants. This will also reduce the need for human intervention on days of extreme heat.
GHFF are susceptible and undergo heat stress when temperatures exceed approximately 40 degrees C, with high rates of mortality experienced on extremely hot days. The current response on such days is direct intervention by the Council; Victorian Department of Environment, Land, Water and Planning; and wildlife carers to spray bats with water from hand-held sprayers to cool and hydrate them as well as to take dehydrated bats into care for rehabilitation.
WSP’s scope of the GHFF Atmospheric Cooling and Artificial Roosts project for the City of Greater Bendigo involves:
- Summarising research, trials and efforts from across Australia that use artificial roost and cooling systems for flying-foxes and provide a recommended approach
- Undertake detailed planning and design of the agreed system(s)
- Provide detailed ecological advice for installation and operation of the system(s)
- Undertake evaluation of the system(s) during the trial period
- Prepare a report post-trial, making recommendations for future years
