Koala News & Science July 2025

by | Jul 30, 2025 | Koala News & Science

koala news science july 2025

KOALA NEWS & SCIENCE

An informative monthly newsletter about successes & important announcements in koala conservation, and the latest scientific publications about koalas.
July 2025
Subscribe here: https://mailchi.mp/808fc4af1ee0/koala-news-science

 

International Court advises that Australia could be liable for climate harm 24 July
The landmark ruling by the International Court of Justice has clarified that countries can’t dodge the harm caused by fossil fuels they export. Hopefully this will slow Australia’s approvals of coal and gas mines, and put existing fossil fuel mines on notice.
https://www.climatecouncil.org.au/resources/worlds-highest-courts-landmark-decision-carries-major-implications-for-australias-climate-obligations/
https://australiainstitute.org.au/post/icj-ruling-confirms-states-have-a-legal-duty-to-act-on-climate-australia-now-faces-a-clear-choice/
https://www.theguardian.com/environment/2025/jul/24/australia-warned-it-could-face-legal-action-over-fossil-fuels-after-icj-landmark-climate-ruling

Mt Pleasant mine, Muswellbrook  blocked NSW 24 July
The MACH Mt Pleasant coal mine expansion approval has been overturned on grounds of climate harm.
https://www.theguardian.com/australia-news/2025/jul/24/significant-legal-breakthrough-as-nsw-court-blocks-coal-mine-expansion-over-emissions#

Big announcement #3 about the same, shrinking NP: Warranmadhaa/Georges River Koala National Park, NSW 30 July 2025
The transfer of 962ha of existing state-owned bushland (currently class 1.3 Conservation & Natural Environments: Other Minimal Use, zoned for public recreation) to National Park is a good thing for future koalas, but it’s not new, it’s not enough, and it’s not what was promised. This latest PR is the third over 3 years over which the national park has shrunk in size, urgency and budget.

Timeline of press releases and promises:
30 July 2025: New national park to protect Sydney’s largest koala population https://www.nsw.gov.au/ministerial-releases/new-national-park-to-protect-sydneys-largest-koala-population
The PR states: “Koalas require large, connected areas of habitat so they can eat, move and breed.”
They sure do. Pity this NP is not any of those things.
The Sydney Basin Koala Network notes that much of the land envisaged for the complete national park is aspirational (private land on the open market), and the critical Mallaty Creek Corridor is still not protected.
https://www.tec.org.au/petition_save_mallaty_creek_koala_corridor

September 2023 : NSW government to set up new national park as it looks to balance koala protections with urban sprawl https://www.abc.net.au/news/2023-09-22/enironment-minister-confirms-koala-national-park/102888598
“The state government will spend $80 million on koala protections, including $43 million from the latest budget*, to establish the Georges River Koala National Park. The national park, which Labor committed to before the state elections, will cover 1,830 hectares along the Georges River, including 1,000 hectares of public land.”
*(That would have been from the 2022-2023, or 2023-2024 Budget. It appears they didn’t spend that $43million as promised, but plan to spend it now?)

March 2023: NSW Labor pledges to protect koala population with new national park in Sydney’s south-west. https://www.theguardian.com/australia-news/2023/mar/04/nsw-labor-pledges-to-protect-koala-population-with-new-national-park-in-sydneys-south-west?
“The commitment would make a koala park in south-west Sydney a reality within three years….The party is also proposing to set up a koala centre to support volunteer wildlife carers in the area and establish infrastructure such as exclusion fencing on roadways and koala crossings.”

3 years will be up in March 2026. But the NSW Office of Environment & Heritage web now states that the establish of the (smaller) park will involve:

  • “transferring existing public lands within the proposed park to the National Parks and Wildlife Service (NPWS) by September 2026″

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Latest Koala Science

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Kramer, G., Duffy, J. and Mella, V.S., 2025. Preliminary Evidence of Chlamydiosis in Koalas of the Greater Geelong Region, Victoria: A Potential Emerging Threat?. Animals, 15(14), p.2048. https://doi.org/10.3390/ani15142048

Koalas (Phascolarctos cinereus) face many threats, with one of them being the disease chlamydiosis caused by the bacterium Chlamydia pecorum, a cause for infertility and one of the main causes of population decline. In New South Wales, Queensland, and the Australian Capital Territory, the koala is an endangered species, but in Victoria, koalas are widespread and overabundant in some areas. The koala populations in the You Yangs Regional Park (YYRP) and Brisbane Ranges National Park (BRNP) in Victoria are reported to be in decline, although there have been no studies looking into population density or disease. The aim of this study was to investigate the presence of C. pecorum in the koala populations of the YYRP and BRNP to understand whether disease may be a cause of concern. DNA was extracted from scats, and qPCR was used to detect the presence and load of C. pecorum. C. pecorum was found in 12/18 (66.7%) scat samples. Clinical signs of disease, age, and sex did not affect infection shedding load. These results confirm the presence of chlamydiosis within the YYRP and BRNP koala populations. More detailed studies are recommended to quantify prevalence of the disease in these populations and to understand the consequences of chlamydiosis in these areas.

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Levengood, A.L., Hohwieler, K., Powell, D. and Cristescu, R.H., 2025. Age Is Just a Number: No Impacts of Scat Ageing on Single Nucleotide Polymorphism Genotyping Using a Target Capture Approach. Ecology and Evolution, 15(7), p.e71755. https://onlinelibrary.wiley.com/doi/abs/10.1002/ece3.71755

Recent advances in DNA sequencing and genotyping technologies are rapidly building our capacity to address ecological, evolutionary, and conservation questions for wildlife. However, wildlife genetic research increasingly relies on samples containing low quantities and quality of DNA, such as non-invasive, archival, and environmental DNA. These samples present unique methodological challenges; for samples collected in the wild, it is important to understand the impact of environmental exposure time or sample ‘age’ on DNA quality and downstream genetic analyses. Here, we aged koala (Phascolarctos cinereus) scats under natural conditions and quantified DNA degradation. We assessed the effect of age on genetic data quality by measuring the proportion of missing single nucleotide polymorphism (SNP) data using DArTCap, a targeted genotyping methodology hypothesised to tolerate degraded DNA. Contrary to other studies, we found koala scat age was not a significant predictor of genotyping quality (i.e., rate of missing SNP calls) in the first 10 days of environmental exposure. We yielded high quality data from 10-day-old scats, but also low-quality data from fresh scats. This study is the first to investigate the effect of scat age on genotyping success using a targeted approach, and DArTCap specifically. These findings support the use of targeted genotyping (such as DArTCap) from scats and provide insights for future research using DNA from non-invasive samples. Targeted genotyping may extend the timeframe, from which accurate data can be obtained from non-invasive samples, increasing potential sample sizes and enhancing our ability to address important questions in population ecology, conservation genetics, and population management.

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Low, Z., Story, M. and Allavena, R., 2025. Analysis of ventricular free wall ratios and cardiac chamber weights in koalas, common ringtail possums, and common brushtail possums. Research in Veterinary Science, p.105790. https://doi.org/10.1016/j.rvsc.2025.105790

Understanding cardiac morphology is essential for elucidating the physiological adaptations of marsupials to their environment, but there is currently a lack of comparative data between species. Therefore, in this study, we investigated multiple aspects of heart morphology in three Australian marsupials: the koala (Phascolarctos cinereus), the common ringtail possum (Pseudocheirus peregrinus), and the common brushtail possum (Trichosurus vulpecula). Cadavers of adult koalas (n = 16), common ringtail possums (n = 16), and common brushtail possums (n = 18) were obtained through veterinary donations. Standard anatomical measurements were conducted to determine body, brain, and heart weights, and heart dimensions, including width, length, and ventricular wall thickness. We found significant morphological differences between the three species, as well as in comparison to other mammals. Koalas had a rounder heart shape and a proportionally smaller brain than ringtail and brushtail possums. All three species had higher left ventricular free wall to right ventricular free wall thickness ratios and lower right ventricle to left ventricle weight ratios than other mammals. In addition, heart weight as a percentage of body weight was lower than that reported for other marsupials. Our results demonstrate that the cardiac morphology of Australian marsupials differs both between species and in comparison to other mammals, possibly owing to an evolutionary response to the physiological demands of their ecological niches.

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Font, M.B., Woolford, L., Jaensch, S., Hayward, D., Hebart, M., Dean, E., Boardman, W.S., Stephenson, T., Kovac, J. and Speight, N., 2025. Biochemical Reference Intervals of Free‐Ranging Koalas (Phascolarctos cinereus) in South Australia. Veterinary Clinical Pathology. https://doi.org/10.1111/vcp.70024

Background Reference intervals (RIs) are an essential tool for assessment of clinical pathology data of animals, and are particularly important for monitoring the health status of free-ranging and captive wildlife, such as koalas (Phascolarctos cinereus).
Objectives The purpose of this study was to: (1) provide comprehensive serum biochemistry reference intervals based on clinically healthy South Australian koalas from two populations, Mount Lofty Ranges (MLR) and Kangaroo Island (KI); and (2) identify any factors that can affect biochemical analytes, including koala retrovirus (KoRV) and Chlamydia pecorum subclinical infection status, age, sex, and population.
Methods Serum biochemistry analytes were determined in 206 clinically healthy South Australian koalas caught from the wild in 2016 and 2018 using a Cobas 8000 Chemistry Analyzer and analyzed using Reference Value Advisor and SPSS v28 Statistical software.
Results Biochemical reference intervals were established. Also, clinically and statistically significant differences in analytes were found based on age for alkaline phosphatase and phosphate, and albumin: globulin ratio, globulins, and total protein, most likely associated with physiological bone growth and immunological development, respectively, as observed in other species. Statistically significant differences between animals subclinically positive for KoRV and Chlamydia pecorum, were found for glucose and gamma glutamyl transferase respectively; however, these were marginal, and their reference intervals were similar.
Conclusions This study is the first to describe serum biochemical reference intervals for clinically healthy South Australian koalas of known Chlamydia and KoRV infection status. It represents an important tool to assist health assessments of koalas by veterinarians, as well as research and population monitoring.

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Phillips, S. and Flanagan, C., 2025. Improving Survivorship and Dispersal Outcomes for Small‐Scale Koala (Phascolarctos cinereus) Translocations: A Case Study From Port Macquarie, New South Wales. Ecological Management & Restoration, 26(3), p.e70019. https://onlinelibrary.wiley.com/doi/abs/10.1111/emr.70019
Processes of koala recovery will require reintroductions into parts of the species’ former range and/or supplementation of other populations to assist their longer term viability. In this study, six wild-caught and three rehabilitated koalas were translocated into a new habitat area. The area into which the translocated koalas were introduced was not the subject of significant habitat use by other koalas at the time of their introduction, and a soft-release protocol that temporarily confined translocated individuals to a tree species known to be preferred for feeding purposes was also employed. Based on the results of a short-term radio-tracking programme, the translocation was deemed successful given no mortalities (including the survival of pouch young known to be present at initial capture), minimal movements away from the release site and rapid commencement of home-ranging behaviours. Male koalas ranged greater distances from their respective release sites than did female koalas. One subadult male koala moved approximately 1.6 km from the release site over a period of 5–6 weeks following release but subsequently returned. Koala activity across the area known to be utilised by the translocated koalas at the time of collar removal was monitored benignly using Spot Assessment Technique sampling at 250 m intervals for the ensuing 3 years, during which time koala activity remained dynamic but statistically constant, implying longer term survival and maintenance of site fidelity by the translocated koalas. The protocols utilised for this translocation are likely to provide a useful tool for future small-scale koala translocation programmes where reintroductions or population supplementation is required.
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Marschner, C., Gray, R., Terkildsen, M., Higgins, D.P., McQuilty, R. and Krockenberger, M.B., 2025. Effect of land use on the concentrations of trace elements and heavy metals in the hair of the koala (Phascolarctos cinereus). Scientific Reports, 15(1), p.27920. https://www.nature.com/articles/s41598-025-12702-3
Increased exposure to environmental contaminants is a concern for local koala (Phascolarctos cinereus) populations where massive transformation or loss of habitat has occurred over the past century as a consequence of increased urbanisation and industrial and agricultural practices. The koala is a specialist eucalypt feeder that relies on an almost exclusive diet of eucalypt foliage. Eucalypts can accumulate elements to varying degrees. Chronic ingestion and bioaccumulation could potentially affect the metabolic pathways of koalas and consequently interfere with detoxification of eucalypt plant secondary metabolites, reduce food intake, and cause long-term health effects. This field study provides the first evidence of the significance of the environmental factor, land use, region and host factors, age and sex, on bioaccumulation of trace element and heavy metal (elements) in koalas. Data on observed ranges of element concentrations are provided from the hair of 328 koalas sampled across eight different regions of NSW and Victoria, Australia. Land use was shown to be the most significant factor affecting trace elements and heavy metal concentrations in koalas, followed by region. Associations between element concentrations and host factors, koala age and sex, were only seen for a small number of elements.

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Previous Koala News & Science here: https://www.wildkoaladay.com.au/koala-news-science/koala-news-science-june-2025/
Written by Janine Duffy President, Koala Clancy Foundation.
with support from Cheryl Egan, Organiser, Wild Koala Day.
Please send your positive, important news & publications to president@koalaclancyfoundation.org.au before 29th of each month for possible inclusion.