A FRIENDS of the Earth survey has revealed as few as 115 koalas are estimated to live in Holey Plains State Park, Mullungdung and Won Wron state forests in total.
Holey Plains was burnt out in 2019, and the koala population there is now minimal.
What makes the findings even more concerning is that koalas of the Strzeleckis and South Gippsland are the only genetically diverse koalas remaining in Victoria and South Australia.
All koalas outside of the region are from translocated populations, which themselves are descendants of a handful of animals moved to French Island and Phillip Island in the late 19th Century.
The genetic diversity of the translocated animals are limited in comparison to the Strzelecki and South Gippsland koalas.
According one of those involved in the surveys, Anthony Amis, better genetic diversity makes populations more robust to changes in the environment over the long term.
“The Strzelecki-South Gippsland koalas therefore constitute one of the most important koala populations in Australia,” he said.
“Yet this significance has meant no additional protection measures by either the state or federal governments.”
Mr Amis said through two scientific studies (published 2014 and 2016) and Friends of the Earth surveys during 2019-20 and 2020-21, about 43,000 hectares of land in South Gippsland and the Strzeleckis had been surveyed for koalas.
Friends of the Earth estimates a koala population between 1200 to 1300 animals across this 43,000ha.
It says in the region, a population of fewer than 2000 animals is likely.
The best quality forest sites (3000ha) in the Strzeleckis have an estimated koala population of 0.25ha per hectare.
Friends of the Earth estimates that for most of the areas outside of the best Strzelecki habitat, the koala population falls dramatically to 0.02 koalas per hectare.
Across 31,000ha of forest (Holey Plains State Park, Mullungdung and Won Wron State Forests) Friends of the Earth estimates between just 115 and 215 koalas.
Its 2021 surveys focussed on Won Wron and Mullungdung state forests, estimating the koala population in Won Wron State Forest to be between 25 and 50 animals, and for Mullungdung between 70 and 140 animals.
The estimates are between 0.01 and 0.02 koalas per hectare — or between 43 to 86 times less than recent estimates by the state government.
Mr Amis said a total 172 surveys (1144 trees) were successfully completed (equivalent to 4300 hectares of forest surveyed) between November 2020 and July 2021.
The 1144 trees included Yellow Stringybark, Yertchuk, Mountain Grey Gum, Messmate and Manna Gum, which accounted for 74 per cent of trees surveyed.
Twelve positive site surveys were located, and only 6.4 per cent of surveyed sites recorded koala scats.
Four or five koalas were sighted at Budgeree, Delburn, Jack Smith Lake and Blackwarry, although the Delburn koala, may have been spotted twice at different times.
Sixty-one scats were located using spot ID.
Trees with scats identified during surveys and spot ID included Mountain Grey Gum, Manna Gum, Yellow Stringybark, Swamp Gum, Yertchuk, Blue Gum, Shining Peppermint, Messmate, Narrow Leaf Peppermint, But But and Strzelecki Gum.
Five species accounted for 83.6 percent of scats found during surveys.
The study confirmed Mountain Grey Gum as the preferred tree species for koalas in the Strzelecki Ranges and South Gippsland region, and confirms the wider dispersal of koalas throughout the Strzelecki’s and the Gippsland Plains.
Areas outside of the survey grid with scats detected included Mullungdung, Won Wron, Longford, Churchill-Traralgon South, Morwell River, Holey Plains, Dutson, Stradbroke, Blackwarry, Delburn, Langsborough and Yarram Golf Course.
Average tree girth at survey sites was 451mm.
Average tree size where a scat was detected was 808mm, highlighting koala preferences for larger trees.
The spot ID surveys found a relatively high number of scats (13) in the Stradbroke-Dutson area.
Almost all of these scats were found along roadsides in the area under Manna Gums and Swamp Gums, with roadsides being used as key koala corridors.
Friends of the Earth estimates about 1000 hectares of koala habitat under control of Gippsland Water also remains unsurveyed in the Dutson-Stradbroke region.
Mr Amis said it appeared that at Mullungdung State Forest, Yellow Stringybark growing near small stands of Swamp Gum were favoured by koalas, and these areas required the establishment of koala buffers.
