Koala's on the Brink: How Evolution’s Specialist Became Vulnerable

1. Introduction: The Evolutionary Paradox of Phascolarctos cinereus

The koala (Phascolarctos cinereus) represents one of the most distinctive and biologically specialized mammalian lineages on the Australian continent. As the sole extant representative of the family Phascolarctidae, the species serves as a unique evolutionary window into the arboreal adaptation of marsupials. Diverging from a common ancestor shared with wombats (family Vombatidae) approximately 30 to 40 million years ago, the koala has evolved a suite of morphological and physiological adaptations that allow it to exploit a niche characterized by high toxicity and low energetic return: the foliage of the genus Eucalyptus.

This dietary specialization, while historically successful in reducing interspecific competition, has rendered the koala exceptionally vulnerable to the rapid environmental fluctuations characterizing the Anthropocene. The modern status of the koala is a paradox; it is simultaneously a global icon of biodiversity, generating billions in tourism revenue, and a species in precipitous decline across significant portions of its range. The narrative of the koala in the 21st century is one of a "syndemic" crisis—a convergence of synergistic threats where habitat loss, climatic instability, and complex disease dynamics interact to accelerate population collapse.

The gravity of this situation was formally recognized in February 2022, when the Australian Federal Government, acting under the advice of the Threatened Species Scientific Committee, uplisted koala populations in Queensland, New South Wales (NSW), and the Australian Capital Territory (ACT) from "Vulnerable" to "Endangered" under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act).¹ This legislative milestone marked the end of a decade of deterioration following the initial 2012 listing and acknowledged a grim trajectory: without radical intervention, the species faces functional extinction in key range states by 2050.³

This report provides a comprehensive, deep-dive analysis of the koala's status as of late 2025. It synthesizes recent advancements in physiological ecology, the molecular biology of disease, and the volatile landscape of conservation policy. It details the catastrophic legacy of the 2019–2020 Black Summer bushfires, the establishment of the Great Koala National Park in 2025, and the cutting-edge genomic battles being waged against the Koala Retrovirus. By examining the intricate biological constraints of the species against the backdrop of accelerating anthropogenic change, we aim to provide a definitive account of where the koala stands in its fight for survival.

2. Physiological Ecology: The Energetic and Thermal Tightrope

To understand the conservation crisis, one must first appreciate the physiological constraints that dictate the koala's existence. The species operates on a tenuous energy budget, defined by the nutritional chemistry of its diet and the thermodynamic limits of its physiology. These intrinsic factors make the koala not just an animal losing its home, but an organism struggling to function within a rapidly heating and chemically altering environment.

2.1 Nutritional Ecology: The Challenge of Eucalyptus

Koalas are obligate folivores, feeding almost exclusively on the leaves of Eucalyptus species, with occasional supplementation from genera such as Corymbia, Angophora, Lophostemon, and Melaleuca.⁵ This diet presents two primary challenges: low caloric density and high toxicity.

2.1.1 Chemical Defense and Detoxification

Eucalyptus foliage is heavily defended by a diverse array of Plant Secondary Metabolites (PSMs). These include terpenes (such as cineole) and formylated phloroglucinol compounds (FPCs), which are potent toxins capable of inhibiting digestion and causing systemic toxicity in most mammals.⁷ The koala's ability to survive on this diet is reliant on a highly efficient detoxification system centered in the liver.

Research into the koala genome and hepatic function has highlighted the critical role of the Cytochrome P450 (CYP450) monooxygenase enzyme superfamily. Specifically, the koala genome shows a significant expansion of the CYP2C and CYP4A subfamilies.⁹ These enzymes facilitate the oxidation of lipophilic terpenes into water-soluble metabolites that can be safely excreted in urine. However, this metabolic detoxification is energetically expensive. The "tax" paid to the liver to neutralize toxins consumes a substantial portion of the energy derived from the leaves, leaving a narrow margin for other metabolic processes such as locomotion, reproduction, and immune response.

This detoxification burden also dictates feeding behavior. Koalas are not indiscriminate browsers; they are highly selective, often sniffing leaves to assess the ratio of nutrients (specifically nitrogen/protein) to toxins (FPCs and tannins). A tree that appears healthy to a human observer may be chemically inedible to a koala if the toxin concentration exceeds the liver's detoxification capacity or if the protein yield is insufficient to justify the metabolic cost of digestion.⁵

2.1.2 The Role of the Hindgut Microbiome

The physical digestion of fibrous leaves is facilitated by the koala's caecum—the longest of any mammal relative to body size (up to 2 meters in length). This organ acts as a fermentation chamber where a complex microbiome degrades cellulose and tannin-protein complexes. A key constituent of this microbiome is the bacterium Lonepinella koalarum, which has been identified as essential for degrading tannins that would otherwise bind to proteins and render them indigestible.⁷

Crucially, this microbiome is not innate. It must be vertically transmitted from mother to offspring through a process known as "pap feeding." During weaning, the mother produces a specialized form of soft faeces (pap) originating from the caecum, which inoculates the joey with the necessary flora. This biological reliance on a specialized microbiome creates a significant vulnerability: the use of systemic antibiotics to treat diseases like Chlamydia can decimate these gut bacteria, leading to "wasting syndrome" where the animal starves to death despite having a full stomach.¹²

2.2 Energetics and Kleiber’s Law

The koala's metabolic rate is exceptionally low, even for a marsupial. This low metabolic rate aligns with the constraints of Kleiber’s Law (the 3/4-power law scaling of metabolic rate with body mass) but is further depressed as an adaptation to their low-energy diet.¹³ By minimizing energy expenditure, koalas can survive on a food source that would be energetically non-viable for a similar-sized placental mammal.

This energy conservation strategy manifests behaviorally as lethargy; koalas sleep or rest for up to 20 hours a day. While often mistaken for laziness or intoxication, this is a critical survival strategy. Any increase in activity—whether caused by disturbance, predator avoidance, or the need to travel further between fragmented habitat patches—rapidly creates an energy deficit that the koala cannot easily recoup.¹⁵

2.3 Thermal Biology: The Limits of Endothermy

As arboreal mammals, koalas are highly exposed to ambient climatic conditions. Their ability to thermoregulate is limited, and they rely heavily on behavioral adaptations to maintain homeostasis.

2.3.1 The Critical Thermal Maximum (CTmax)

Recent physiological studies have defined the thermal limits of the koala with high precision. The species maintains a thermal neutral zone (TNZ) roughly between 14.5 degrees Celsius and 24.5 degrees Celsius.¹⁶ Within this range, the koala maintains its core body temperature (Tb) with minimal metabolic effort.

However, as ambient temperatures (Ta) rise above this zone, the koala must actively dissipate heat. Unlike humans who sweat, koalas rely on evaporative cooling via panting and cutaneous water loss. This mechanism is water-intensive. In a drought-prone environment, relying on water loss for cooling is a dangerous trade-off.

Field research utilizing thermal imaging and internal loggers has identified a lethal physiological limit. During extreme heatwaves, koala body temperatures have been recorded rising to 40.8 degrees Celsius.¹⁷ This temperature represents the upper threshold of survival, often referred to as the Critical Thermal Maximum (CTmax), beyond which protein denaturation and organ failure (heat stroke) occur.

2.3.2 Behavioral Thermoregulation: Tree Hugging

To delay the onset of heat stress, koalas exhibit a behavior described as "tree-hugging." By pressing their ventral surface (which has thinner fur) against the trunks of large trees, they facilitate conductive heat transfer. Large tree trunks can be up to 5 degrees Celsius cooler than the ambient air temperature.¹⁸ Models suggest that this behavior can reduce the koala's need for evaporative cooling by over 50%, saving approximately 18% of their total water budget.¹⁸

This finding underscores the importance of mature, large-diameter trees in koala habitat. Young regeneration forests, while providing food, often lack the thermal mass required to serve as effective heat sinks during extreme weather events.

3. The Threat Landscape I: Environmental and Anthropogenic Pressures

The physiological constraints described above render the koala uniquely susceptible to the environmental changes driven by human activity. These threats are not isolated; they are cumulative and synergistic.

3.1 The CO2 "Nutritional Trap"

One of the most insidious threats to koala viability is the alteration of atmospheric chemistry. Elevated levels of carbon dioxide (CO2) enhance the photosynthetic rate of plants, a phenomenon known as carbon fertilization. While this increases biomass, it fundamentally alters leaf chemistry.

Research has shown that Eucalyptus leaves grown under elevated CO2 conditions exhibit a higher carbon-to-nitrogen ratio. This results in a reduction in protein concentration (nitrogen) and an increase in carbon-based secondary metabolites (tannins and phenols).20

This creates a "nutritional trap":

1. Reduced Protein: Koalas must consume more leaf mass to meet their daily protein requirements.

2. Increased Toxicity: Consuming more leaf mass increases the ingestion of toxic PSMs, potentially exceeding the liver's detoxification threshold.

3. Digestive Inhibition: Increased tannins bind to the limited protein available, further reducing digestibility.

The implication is that the carrying capacity of Australian forests is declining even without a reduction in tree numbers. A forest that supported 100 koalas in 1990 may only support 50 in 2050 solely due to the degradation of food quality.²²

3.2 The 2019–2020 Black Summer Bushfires

The 2019–2020 bushfire season was a catastrophic event that fundamentally shifted the conservation trajectory of the species. The fires were unprecedented in their scale, intensity, and duration, burning approximately 24% of koala habitat on public land in NSW.³

3.2.1 Mortality Estimates

A landmark report commissioned by the World Wide Fund for Nature (WWF) estimated that over 60,000 koalas were killed, injured, or displaced by the fires.²³

• Kangaroo Island: This population, previously considered a secure "insurance population" due to its isolation and lack of Chlamydia, suffered devastating losses. Tens of thousands of animals perished as high-intensity fires swept through the plantations and native bushland.²⁴

• NSW North Coast: In the primary koala habitats of northern NSW, analysis using Google Earth Engine Burnt Area Map (GEEBAM) data indicated that in areas with fully burnt canopies, koala mortality approached 70–100%.²⁴

3.2.2 Long-term Ecological Impacts

The fires did more than kill individuals; they fragmented meta-populations. Many survivors were left in isolated "unburnt" refugia. However, these refugia were often sub-optimal habitat located in gullies or on poorer soils, leading to subsequent starvation and density-dependent disease outbreaks. The destruction of the canopy also removed the thermal refuge provided by large trees, leaving survivors more exposed to the heatwaves that often follow fire seasons.²⁶

3.3 Habitat Loss and Fragmentation

Despite the Endangered listing, habitat destruction remains the primary driver of decline. In Queensland and NSW, land clearing for agriculture (particularly beef cattle grazing), urban development, and mining continues to reduce the available range.¹

Fragmentation exacerbates all other threats. As continuous forests are broken into smaller patches, koalas are forced to descend to the ground to travel between food trees. This terrestrial movement significantly increases their exposure to two lethal threats: vehicle strikes and domestic dog attacks.

3.3.1 Vehicle Strikes

Vehicle strikes are a major cause of mortality, particularly in peri-urban areas. The conflict between koala movement corridors and road infrastructure is acute.

• Peak Downs Highway (Central Queensland): A recent study analyzing data up to 2024 highlighted the severity of this threat. On a single 51km stretch of the Peak Downs Highway, 145 koalas were struck in one year, with an 83% mortality rate. The study noted that these animals were otherwise healthy, representing a significant drain on the reproductive potential of the local population.²⁹

• NSW Hotspots: Similar patterns are observed in NSW, where the biolink report (March 2025) identified 581 recorded strikes in the Sydney Basin, emphasizing the need for exclusion fencing and underpasses.³⁰

3.3.2 Dog Attacks

Domestic and feral dogs are responsible for a significant proportion of koala admissions to wildlife hospitals. In NSW, dog attacks account for approximately 25.6% of recorded koala deaths, a figure that rises to 44% in urbanized areas.³² Attacks are often fatal even if the physical trauma appears minor, as the crushing force of a dog's jaw can cause massive internal organ damage and the bacteria from the dog's mouth can lead to lethal sepsis.³³

4. The Threat Landscape II: The Disease Syndemic

The decline of the koala is not driven by environmental factors alone. The species is currently battling a "syndemic"—a synergistic interaction between two major pathogens: Chlamydia pecorum and the Koala Retrovirus (KoRV). The interplay between these diseases and the stress caused by habitat loss creates a feedback loop that accelerates population decline.

4.1 Chlamydia pecorum: The Silent Killer

Chlamydiosis is the most pervasive infectious disease affecting koalas. While the bacteria Chlamydia pneumoniae also affects koalas, Chlamydia pecorum is the primary agent of severe disease.³⁴

4.1.1 Pathology

The disease manifests primarily in two forms:

1. Ocular Disease (Keratoconjunctivitis): Chronic inflammation of the conjunctiva leads to proliferation of tissue, obscuring the eye and causing blindness. Blind koalas cannot navigate the canopy to feed or escape predators.

2. Urogenital Disease: Infection of the urinary tract causes severe cystitis, leading to a condition known as "wet bottom" due to urinary incontinence and staining of the fur. In females, the infection ascends to the reproductive tract, causing large ovarian cysts and fibrosis of the oviducts (bursitis). This results in permanent infertility.¹²

4.1.2 Prevalence and Impact

In some populations in South East Queensland and Northern NSW, chlamydia prevalence reaches 100%, and "functional extinction" occurs because virtually all females are rendered infertile. Recruitment of new joeys drops to zero, and the population slowly ages and dies off.²⁸

4.2 Koala Retrovirus (KoRV): Evolution in Real-Time

The Koala Retrovirus (KoRV) represents a profound biological event: the endogenization of a retrovirus into a mammalian genome occurring in real-time. KoRV is a gammaretrovirus, similar to the Gibbon ape leukemia virus, that is transitioning from an exogenous virus (infecting from the outside) to an endogenous viral element (inherited in the DNA).³⁶

4.2.1 Subtypes: KoRV-A vs. KoRV-B

Understanding the distinction between KoRV subtypes is critical for conservation management:

• KoRV-A (Endogenous): This subtype has successfully integrated into the germline of all koalas in Queensland and NSW. It is vertically transmitted from parent to offspring in the DNA. While ubiquitous in the north, it is generally considered less pathogenic, although high viral loads are associated with immunodeficiency.³⁷

• KoRV-B (Exogenous): This subtype is currently exogenous and transmitted horizontally (animal-to-animal) or via maternal milk. It has not yet fixed in the genome. KoRV-B is significantly more pathogenic than Type A. It is strongly associated with the development of leukemia, lymphoma, and severe, treatment-resistant chlamydiosis.³⁹

4.2.2 Geographic Distribution and Spread

Historically, a "viral divide" existed. Northern populations (QLD/NSW) were KoRV-positive, while Southern populations (Victoria/SA) were largely free of the virus (KoRV-negative). However, recent surveys (2024-2025) indicate that KoRV-A is spreading southwards and is now present in Victorian populations, likely due to unauthorized translocations or natural dispersal.³⁷ The fear is that the virulent KoRV-B subtype will follow, decimating the immunologically naive southern populations.

4.3 The "Genomic Immunity" Breakthrough (2025)

In a significant scientific development published in late 2024/early 2025, researchers identified a mechanism of natural resistance. The study, involving researchers from the University of Queensland and UMass Chan Medical School, discovered that some koalas have evolved a "genomic immune system" against KoRV-A.⁴¹

The mechanism involves a specific integration of the KoRV-A provirus into the 3' untranslated region (UTR) of a gene called MAP4K4. This integration acts as a trigger for the production of piRNAs (piwi-interacting RNAs). These piRNAs recognize the viral RNA and silence it, effectively suppressing the replication of the virus. Koalas carrying this specific "unsilenced" integration show significantly reduced viral loads (up to 10-fold lower) in their germline and reduced rates of new viral insertions.⁴² This discovery offers a potential genetic marker that could be used to select naturally resistant koalas for breeding and translocation programs.

5. Conservation Status and the Legislative Landscape

The deteriorating ecological status of the koala has forced a slow and often reactive evolution of conservation law.

5.1 The EPBC Act Uplisting (2022)

In April 2012, the Australian Federal Government listed the combined koala populations of Queensland, NSW, and the ACT as "Vulnerable." A decade later, it became clear that this listing had failed to halt the decline. On February 12, 2022, the Minister for the Environment formally upgraded the listing to "Endangered".¹

This uplisting acknowledged that the "Vulnerable" status had provided insufficient protection against habitat clearing. The "Endangered" status triggers higher scrutiny for development assessments under the EPBC Act, theoretically requiring stronger offsets and stricter approval conditions for projects impacting koala habitat.⁴³ However, critics argue that the EPBC Act remains structurally weak, often facilitating "death by a thousand cuts" through the approval of numerous small-scale clearing applications.¹

5.2 The 2050 Extinction Prediction

A pivotal moment in public policy was the 2020 NSW Legislative Council inquiry into koala populations. The inquiry's final report concluded that, based on current trends of habitat loss and the impact of the bushfires, the koala would become extinct in the wild in NSW by 2050 without urgent government intervention.³

This prediction was based on:

1. Historical Decline: A 28-33% decline in population between 1990 and 2010.

2. Fire Impact: The loss of 24% of habitat in a single season (2019/20).

3. Climate Projections: Models predicting that western populations (e.g., Pilliga, Gunnedah) would become climatically unviable due to heatwaves and drought.⁴⁵

This 2050 deadline has since become the central narrative anchor for conservation advocacy and the benchmark against which all government actions are measured.

6. Major Conservation Interventions (2022–2025)

The urgency of the Endangered listing and the 2050 deadline sparked a flurry of conservation activity, culminating in major developments in 2025.

6.1 The Great Koala National Park (GKNP)

For years, conservation groups like the National Parks Association of NSW and the Australian Koala Foundation advocated for a "Great Koala National Park" on the NSW Mid-North Coast—a global biodiversity hotspot.

6.1.1 Establishment and Boundaries

On September 7, 2025 (National Threatened Species Day), the NSW Government formally announced the boundaries of the Great Koala National Park.⁴⁷ The park was designed to connect 176,000 hectares of state forests with existing national parks, creating a contiguous reserve of approximately 476,000 hectares. This massive reserve is intended to protect distinct "koala hubs" with high genetic diversity and serve as a climate refuge.⁴⁹

6.1.2 The Logging Moratorium

Crucially, the announcement included an immediate moratorium on timber harvesting within the 176,000 hectares of state forest slated for inclusion. This was a response to intense criticism that logging had intensified in these proposed areas during the assessment phase in 2023 and 2024.⁵⁰

6.1.3 Socio-Economic Controversy

The establishment of the park was not without conflict. The timber industry and some local community groups raised concerns about economic impacts, citing the loss of approximately 300 direct jobs in the forestry sector. To mitigate this, the government announced a comprehensive industry support package, including worker transition payments and investment in regional tourism infrastructure.⁴⁸

6.2 The Chlamydia Vaccine: From Trial to Approval

One of the most significant scientific achievements of the decade occurred in late 2025 with the regulatory approval of the world’s first koala chlamydia vaccine.

6.2.1 Development: Peptide vs. Recombinant Protein

The path to a vaccine involved a scientific debate over the best antigen. Early trials explored synthetic peptide vaccines, which targeted specific epitopes of the bacterium. However, trials led by Professor Peter Timms at the University of the Sunshine Coast (UniSC) demonstrated that a recombinant protein vaccine (utilizing the Major Outer Membrane Protein, or MOMP) induced a broader and more durable immune response, particularly the production of mucosal IgA antibodies essential for protecting the eyes and reproductive tract.⁵¹

6.2.2 Approval and Efficacy

In late 2025, the Australian Pesticides and Veterinary Medicines Authority (APVMA) granted approval for the recombinant MOMP vaccine.³⁵

• Key Finding: Field trials conducted over ten years showed that the vaccine reduced chlamydia-related mortality in wild populations by 65%.¹²

• Mechanism: It not only prevents infection but also reduces the shedding of bacteria in infected animals, lowering transmission rates.

• Deployment: The approval allows wildlife hospitals to vaccinate all animals coming into care before release, effectively turning released animals into immune buffers in the wild.

6.3 The 2025 Translocation Failure

While the vaccine provided hope, a translocation program in 2025 served as a grim reminder of the complexities of managing wild populations.

In an effort to re-establish a population in the South East Forest National Park, the NSW Government authorized the translocation of 13 koalas. By July 2025, it was revealed that 7 of the 13 animals had died.55

• Causes of Death: Veterinary reports indicated that several animals died from septicaemia and stress-related complications. The failure was attributed to "poor thrift"—essentially, the animals failed to adapt to the new environment, possibly due to subtle differences in leaf chemistry or the stress of translocation weakening their immune systems.⁵⁷

• Consequences: This event led to a suspension of some translocation activities and a review of protocols, highlighting that simply moving koalas to "protected" areas is not a silver bullet if the animals cannot metabolically adapt to the specific local Eucalyptus species.⁵⁸

7. Regional Status Reports

The status of the koala varies dramatically across its range, requiring a nuanced regional analysis.

7.1 Queensland (Endangered)

• South East Queensland (SEQ): The "Koala Coast" (Redlands, Moreton Bay) has seen catastrophic declines of up to 80% since the 1990s due to urbanization. The population is heavily impacted by vehicle strikes and dog attacks.

• Central/Western QLD: Populations here are lower density and threatened by heatwaves. However, 2025 acoustic surveys detected koalas in unexpected locations, such as Quilpie (478km west of Roma), suggesting some persistence in arid zone riparian refugia.⁵⁹

7.2 New South Wales (Endangered)

• North Coast: The stronghold of the NSW population. While severely burnt in 2019, this region is the focus of the Great Koala National Park.

• Pilliga/Gunnedah: Once a thriving population west of the Great Dividing Range, the Pilliga population is considered functionally extinct or in terminal decline due to heatwaves and drought rendering the foliage inedible (via the CO2 trap).

• South Coast: Populations are small, fragmented, and were heavily impacted by the Black Summer fires. This is the site of the failed 2025 translocation.

7.3 Victoria and South Australia (Not Listed as Endangered)

• Status: In stark contrast to the north, some Victorian and SA populations (e.g., Cape Otway, Kangaroo Island before the fires) are considered "overabundant."

• The Genetic Problem: These populations are largely founded from a handful of individuals moved to islands in the early 20th century to escape fur hunting. They suffer from extremely low genetic diversity (founder effect). This manifests in physical abnormalities (e.g., testicular aplasia) and a lack of adaptive potential to new diseases.⁶⁰

• Management: Management here often involves fertility control (implants) or even culling to prevent over-browsing and starvation, creating a complex dual-narrative of "too many" in the south and "too few" in the north.

8. Monitoring and Data Controversies

8.1 The "Acoustic" Population Boom

In December 2025, the NSW Government and CSIRO released updated population estimates based on the National Koala Monitoring Program. The data suggested that the NSW koala population could be as high as 274,000, with national estimates nearing 900,000.⁶²

This figure was significantly higher than the 2012 estimates (which pegged the national population around 300,000–500,000). However, experts caution that this is not a biological recovery.

• Detection Artifact: The increase is driven by the use of acoustic recorders and thermal drones which detect cryptic animals in low-density habitats that were previously missed by human spotters.⁵⁹

• The "Paper" Recovery: Conservationists argue that these numbers are dangerous if they lead to complacency. Finding 10,000 koalas in a forest that is slated for logging does not mean the species is safe; it means 10,000 animals are about to lose their habitat.⁶³

9. Conclusion: The Critical Decade

As of late 2025, the koala stands at a precipice. The species is trapped in a pincer movement between ancient biological constraints and modern anthropogenic pressures.

Ecologically, the koala is fighting a losing battle against thermodynamics and chemistry. As Australia heats up, the window of temperatures wherein a koala can survive without lethal dehydration is closing. Simultaneously, the very food they eat is becoming less nutritious and more toxic due to rising CO2.

Pathologically, the syndemic of KoRV and Chlamydia is reshaping the demography of the species, rendering vast numbers of females infertile and shortening lifespans through cancer and renal failure. The discovery of genomic immunity in MAP4K4 and the approval of the UniSC vaccine are monumental scientific wins, but they are tools, not cures. A vaccine cannot protect an animal from a bulldozer or a bushfire.

Politically, the establishment of the Great Koala National Park is a historic victory, securing a future for the populations of the Mid-North Coast. However, the failure of the South East Forest translocation serves as a sobering check on our ability to engineer nature. It reminds us that habitat quality is nuanced and that simply moving animals to "green" areas on a map is often insufficient.

The trajectory toward 2050 remains uncertain. If the "paper population" increase from 2025 monitoring leads to a relaxation of protections, extinction in the wild in NSW remains a probable scenario. However, if the data is used to target protections for the newly identified refugia, and if the vaccine can be deployed at scale, Phascolarctos cinereus may yet persist. The koala has survived for 25 million years; its survival through the next 25 depends entirely on the decisions made in this critical decade.

Data Appendix: Key Metrics and Statistics

Metric	Value / Status	Source
Federal Conservation Status	Endangered (QLD, NSW, ACT)	1
Predicted Extinction (NSW)	2050 (without intervention)	3
Chlamydia Vaccine Efficacy	65% reduction in mortality	12
Koala Thermal Limit (CTmax)	~40.8 degrees Celsius	17
Black Summer Fire Impact	>60,000 individuals impacted	23
NSW Population Estimate (2025)	~274,000 (Controversial update)	62
Translocation Mortality (2025)	7 deaths / 13 animals (SE Forest NP)	56
Vehicle Strike Mortality (Peak Downs Hwy)	83% (145 strikes in 1 year)	29
Dog Attack Mortality (NSW)	25.6% of all recorded deaths	32

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