Road and rail barriers which prevent wildlife crossing between the Royal and Heathcote national parks will be among issues discussed at a webinar led by two highly respected experts in this field.
The event to be held by Sutherland Shire Environment Centre on Tuesday April 5 at 7pm has taken on extra significance with the federal government's decision in February to increase the level of protection for koalas by listing them as endangered species, rather than their previous designation of vulnerable.
Environment centre spokeswoman Catherine Reynolds said local environment groups were excited about an increasing number of koala sightings around the shire in the last few years, and there was growing concern about protecting the local population.
"Environment groups have been waiting since mid 2021 for the release of a Transport for NSW report detailing measures to help prevent koalas being killed on Heathcote Road, including a possible underpass at Deadmans Creek," she said.
Dr Reynolds said the webinar would examine this area along with the need for wildlife crossings of the the M6 (F6) and South Coast train line that separate the Royal National Park from other areas of habitat.
"The most recent koala sighting we know of in the Royal National Park was in 2021," she said.
"But these koalas are a bit of a mystery. We don't know how many are currently living in the Royal, or how they came to be there.
"How would koalas access the Royal from Heathcote National Park, the Woronora catchment, and bushland at Holsworthy?"
One of the speakers in the webinar, Associate Professor Ross Goldingay, has been conducting research into road barriers and their mitigation for over 20 years.
He made the case in a scientific paper 10 years ago for the road and rail barriers between the Royal and Heathcote National Parks to be addressed.
The other speaker, Josie Stokes, was previously the Senior Biodiversity Specialist at Transport for NSW, and is a recognised road ecology expert who has prepared over 300 environmental impact assessment reports on wildlife crossing at different locations across Australia.
Associate Professor Ross Goldingay said "Many people will see Royal National Park as a very large chunk of bush, but the truth is Royal is a habitat island. Road and rail corridors, and large areas of residential development, isolate it from larger areas of habitat to the west. Many species in Royal will have populations that need to be connected to those to the west to have long-term viability."
"Koalas are a visible sign of the malfunction that is representative of what is happening for other species that we don't see", he said. "Koalas need to have movement between broad areas of habitat from Campbelltown to Royal, and yet they are frequently being killed on the roads that subdivide these areas. I can attest to having seen a koala dead beside the road near Lucas Heights in 2018.
"Wildlife like koalas need to move to find food and mates, and some individuals need to move longer distances to find suitable habitat. All of this keeps populations healthy but roads and other developments create various kinds of barriers. Research has progressed in the last 10 years so we now have an understanding of how we might reduce these impacts.
"Inbreeding due to lack of genetic diversity can also occur if their ability to find new mates is limited. Under natural conditions they can travel surprising distances, and over generations a colony can disperse quite widely in all directions. Koalas like to explore and move around to find a mate or better food sources."
Dr Reynolds said a 2021 National Parks and Wildlife Service report stated barriers such as the M6 motorway and train line were "likely to be a major factor in the local extinction of several species".
The webinar will look into questions such as how often wildlife crossings are used by native animals; if wildlife crossings allow animals to repopulate an area after catastrophic bushfires; and whether infrared cameras are a reliable detection method for finding out which animals use various crossings?.
Dr Reynolds is curious about koalas that have been found in the Royal.
"In 1938 it was reported that the Royal National Park Trustees were going to attempt to breed koalas in the Royal", she said.
"Are the Royal National Park koalas a result of this breeding experiment? They may have also come from around Campbelltown originally, somehow managing to cross the freeway and train line?.
"What we do know is that it's not good when wildlife corridors are blocked, and the National Parks and Wildlife Service have been flagging this issue in relation to the Royal National Park in various reports for over 50 years.
"We're hoping to find out more about what can be done to address this.
"The NSW government recently committed around $7 million to upgrade Mona Vale Road and underpasses and overpasses being put in there are restoring connectivity between Ku-ring-gai and Garigal national parks.
"Government agencies take this issue seriously - not just in NSW, but across Australia, and internationally.
"With koalas in Australia being officially recognised as endangered the question of what we can do to protect them has become far more pressing."
To book tickets for the webinar: https://us02web.zoom.us/webinar/register/WN_4TfeIuQ1Q4aNm6oG1-03Iw
More information: https://www.ssec.org.au/our-campaigns/koalas-and-resilient-habitat-in-the-sutherland-shire/
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