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New Scientific Study Reveals Likely Origins of Strzelecki Koala

A new scientific study by Biolink Ecological Consultants and funded by the Myer Foundation has revealed that Morwell National Park and surrounds are likely to be the source population of the highly significant Strzelecki koala, the only genetically diverse koala population remaining in Victoria and South Australia. The study shows for the first time that both genetic and records analysis point to the same area.

The Strzelecki koala is the only relic koala population remaining in Victoria and South Australia, meaning that the population is crucial in terms of ensuring the survival of the species in Victoria and South Australia. All other koala populations are the result of translocations from genetically 'compromised' island populations. Friends of the Earth estimates that the population of the Strzelecki koala may be as few as 2,500 animals.

Strzelecki Koala: Photo Susie Zent (Friends of Gippsland Bush)

The Biolink study initially started with a research project concerning koalas and habitat within the Brataualung Forest Park. The Park will eventually form an 8,000 ha corridor linking Gunyah Gunyah Rainforest Reserve to Tarra Bulga National Park. 2,400 ha of the park was reserved in July 2018 by the Victorian State Government, with the remaining 6,000ha to be reserved by 2027.

Biolink used Areas of Regional Koala Significance (ARKS) mapping for the first time in Victoria. ARKS is the basis of the NSW Government's Koala Conservation Strategy, but is not used by the Victorian Government. Sightings were partitioned into 6 year koala generations which revealed a progressive radiation from core areas. 

Extent of occupancy, area of occupancy and generational persistence (based on sightings over the past 70 years) were also assessed. Biolink conducted field work in the Forest Park in September 2022. They then combined that work with past genetic cluster research by Federation University's Faye Wedrowicz. It was this unique combination that highlighted the significance of Morwell National Park and surrounds.

9 ARKS were located within the study area, with only one (Morwell 1) likely to be viable of maintaining a koala population over the long term. 4000 to 5000ha of habitat is required to sustain a koala population. Survival is reliant on a population of approximately 500 animals. Morwell 1 includes significant areas of the Brataualung Forest Park.

Location of ARKS within study area. Level 1 ARKS are in light green, Level 2 ARKS in mauve. Brataualung Forest Park is outlined in white. Morwell National Park is located near Yinnar South on Map. Koala sightings over different koala generations are located by dots.

In terms of the Brataualung Forest Park, habitat containing Preferred Koala Feed Trees (PKFT's) in the Park was limited although 71% were being utilised by koalas in the Park. Past work in the Strzelecki's has identified Mountain Grey Gum and Blue Gum as PKFT's,  however Mountain Ash dominates much of the wet forest of the Strzelecki's indicating that estimations of koala numbers by the Victorian State Government in higher elevations of the Strzelecki Ranges have been over estimated by 400%. Lower elevations have higher carrying capacity.

The area to the south east of Morwell National Park is dominated by pine plantations owned by Hancock Victorian Plantations. The distance between Morwell National Park to the northern most portion of the Brataualung Forest Park is approximately 8km. Koala corridors need to be established between the two Reserve areas.

Recommendations from the report include: 

*Extending the planting of Mountain Grey Gums and Blue Gums in the Brataualung Forest Park.

*The need to link Morwell National Park to the Brataualung Forest Park (a distance of 8km. Much of this land is privately owned by Hancock Victorian Plantations and is rapidly being converted to pine plantations).

*More monitoring to include C3 genetic cluster first published by Wedrowicz.

*Inter-generational field sampling every 2-3 years,

*Identify and survey, additional field sites within the Brataualung Forest Park

*Restrict monitoring sites to those with Preferred Koala Feed Trees.

According to Friends of the Earth Land Use Researcher Anthony Amis, the report is highly significant in terms of better understanding the unique factors that have contributed to the survival of this special animal. The story of the Strzelecki koala is one of an animal surviving against overwhelming odds and historical practices over the last 150 years which have included land clearing, forestry farming, bush fires and the plantation industry. The koala has been slowly recovering over the past decades, but still faces monumental hurdles in ensuring its long term survival. Biolink have produced a brilliant assessment of the situation. We are still patiently waiting for the next hand back of 4000 hectares of land to the Brataualung Forest Park by the Victorian State Government.

For a copy of the report see here  or for summary report and more information: [email protected]




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