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Enterobacter cloacae K1 isolated from koala (Phascolarctos cinereus) was used for the simultaneous production of glucose-based biofuels. Genomic analysis showed genes related to bio-2,3-butanediol (BDO), bioethanol (BE), and biohydrogen (BH) production, such as hydrogenase 3, α-acetolactate decarboxylase, α-acetolactate synthase, and three alcohol dehydrogenases. To optimise the multi-biofuel production, a central composite design was applied to assess the effect of glucose concentration, pH, and temperature. Optimal conditions were an initial pH of 9.2, 28.5 °C, and 78.9 g dm−3 glucose, obtaining 22.79 ± 0.32 g dm−3 BDO, 10.8 ± 0.22 g dm−3 BE, and 6378.4 ± 857.8 cm3 dm−3 of BH. Maximum yields of 0.31 g g−1, 0.16 g g−1, and 0.49 mol mol−1 were achieved for BDO, BE, and BH, respectively. The main factor that affected the response variables was the square term of temperature. This work strengthens the novel approach of the simultaneous production of biofuels by using the metabolic abilities of E. cloacae K1. [Display omitted] • First report of multi-biofuel production by E. cloacae K1 isolated from koala. • Butanediol, ethanol, and biohydrogen are the main products obtained from glucose. • Optimal conditions are an initial pH of 9.2, 28.5 °C, and 78.9 g dm−3 glucose. [ABSTRACT FROM AUTHOR]

Cryptococcosis is a fungal disease in humans and animals, caused by the Cryptococcus neoformans and Cryptococcus gattii species complexes. Clinical cryptococcosis primarily manifests as upper respiratory tract disease; however, dissemination to other organs, particularly the brain, can occur. Nasal colonisation and subclinical cryptococcosis are common in koalas (Phascolarctos cinereus) due to their shared environmental niche with Cryptococcus: Eucalyptus trees. However, for reasons that remain unclear, the prevalence of clinical disease is low in koalas. Interactions between respiratory pathogens and the nasal mycobiome are thought to play a role in the development and progression of numerous respiratory diseases. As such, this study aimed to characterise the mycobiome of the nasal vestibule in koalas with and without evidence of cryptococcal colonisation and subclinical disease via the next-generation sequencing (NGS) of the ITS1 region of the fungal internal transcribed spacer (ITS) gene. Samples were collected from 47 koalas from a population of free-ranging koalas in the Liverpool Plains, NSW, Australia, with a known history of Cryptococcus exposure and nasal colonisation. Of the 47 animals tested, 6.4% were culture-positive only, 4.3% were seropositive only, and 2.1% were culture- and seropositive. C. gattii was detected in four samples via NGS. C. neoformans was not detected via NGS. There were no significant differences in the nasal mycobiomes of Cryptococcus-positive and -negative animals; thus, we could not establish a definitive association between the mycobiome and infection outcomes. We identified a number of fungal genera that were significantly more abundant in samples from Cryptococcus-positive animals, but there was no apparent relationship between these genera and the development of cryptococcosis. This study represents the first investigation of the nasal mycobiota of wild koalas. Further studies involving koalas with clinical disease are necessary to determine the role of the nasal mycobiota in the development of cryptococcosis. [ABSTRACT FROM AUTHOR]

Chlamydiosis is a common infectious disease impacting koalas and is a major cause of population decline due to resulting mortality and infertility. Polymorphisms of major histocompatibility complex (MHC) genes influence chlamydial disease outcomes in several species but koala studies have produced variable results. We aimed to identify the MHC II DAB and DBB repertoire of koalas from Liverpool Plains, NSW, a population heavily impacted by chlamydiosis. We compared variants between two studies, age cohorts and chlamydial infertility groups. Four DBB and eight DAB alleles were identified. The mean number of DAB alleles per individual increased and allele frequencies differed relative to a previous study, however the mean number of DBB alleles per individual decreased generationally, between age cohorts. DAB allele frequencies differed among fertility groups but contributing alleles could not be identified. While there is a likely role of MHCII in the complex pathogenesis of chlamydiosis, this study suggests that single gene association studies are not appropriate for understanding the impact of host genetics on koala chlamydiosis. A shift to larger multivariate studies is required to yield functional information on complex immunological interactions, and to inform targeted koala conservation across its diverse range and host–pathogen–environment contexts. [ABSTRACT FROM AUTHOR]

Wildlife diseases are major players in local and global extinctions. Effective disease surveillance, management and conservation strategies require accurate estimates of pathogen prevalence. Yet pathogen detection in wild animals remains challenging. Current gold standards often require samples collected through veterinary examination, but this method is costly, intensive, invasive, and requires specialised staff and equipment. Collection of non-invasive samples, such as scats, is an effective monitoring tool which can be deployed at large scale, as scats contain DNA of both host and pathogens. The koala (Phascolarctos cinereus) is listed as 'endangered' under the EPBC Act 1999, with chlamydial disease representing a major threat. Here, we present a new approach that combines restriction-enzyme associated sequencing and targeted-sequence-capture genotyping, namely DArTcap, to detect Chlamydia pecorum in koala scats. We found this method has similar accuracy to current gold standards (qPCR of swab samples), with a sensitivity of 91.7% and a specificity of 100%. This method can be incorporated into existing koala genetic studies using marker panels, where population attributes can be estimated alongside C. pecorum presence, using the same scat samples, with the option to add further markers of interest. Such a one-stop-shop panel would considerably reduce processing times and cost. [ABSTRACT FROM AUTHOR]

Background: Wildfires can have complex effects on wildlife populations. Understanding how post-fire conditions affect the movement ecology of threatened species can assist in better conservation and management, including informing the release of rescued and rehabilitated animals. The 2019–2020 megafires in Australia resulted in thousands of animals coming into care due to injury or concerns over habitat degradation. This included hundreds of koalas (Phascolarctos cinereus), for which relatively little was known about how fire affected habitat suitability, or when rehabilitated animals could be returned to burnt areas. Methods: We compared the movements of koalas across three experimental groups–non-rehabilitated koalas in burnt habitat, non-rehabilitated koalas in nearby unburnt habitat, and rehabilitated koalas returned to their rescue location in burnt habitat in New South Wales, Australia. We GPS-tracked 32 koalas for up to nine months and compared, across treatment groups, home ranges, mean nightly distance moved, the farthest distance moved from their release site and total displacement distance. Results: We found no differences in koala movements and home range size between non-rehabilitated koalas in burnt and unburnt habitat. However, rehabilitated koalas moved farther from their release site, had larger displacement distances, and larger home ranges than non-rehabilitated individuals. Regardless of their experimental group, we also found that males moved further than females each night. Additionally, our resource selection analysis showed that, koalas preferred low and moderately burnt habitats over all other fire severity classes. Conclusions: Experimental frameworks that incorporate "treatment" and "control" groups can help isolate disturbance effects on animal movements. Encouragingly, despite catastrophic wildfires, burnt woodlands provided adequate resources for koalas to persist and recover. Furthermore, rehabilitated koalas re-integrated into the burnt landscape despite moving farther from their release sites than non-rehabilitated individuals. Studies like this improve our understanding of the ecological impacts of fire on species and their habitats, and will be instrumental in informing wildlife management and conservation efforts as wildfires increase in frequency and severity worldwide in response to climate change. [ABSTRACT FROM AUTHOR]

Australia's offset framework requires that permitted development impacts on nationally threatened species should be fully counterbalanced using biodiversity offsets. The current offsets framework was established in 2012, the same year that the iconic koala Phascolarctos cinereus was listed as threatened. We examined every development impact on koala habitat that was permitted under national biodiversity laws (the EPBC Act 1999) from 2012 until the end of 2021, shortly after which the koala was uplisted from vulnerable to endangered (n = 98). We analyzed the application of the national environmental offset framework in each case. In this period, more than 25,000 hectares of koala habitat were approved for removal, most in the state of Queensland (96%) and for mining (76%). Although most clearing of koala habitat is attributable to agricultural activity and ostensibly requires approval under the EPBC Act, we found zero referrals for agricultural clearing. A total of 62 projects included offset requirements for koalas, but for only 14 projects could we find details used in the offset calculation. All but one appeared to include implausibly optimistic assumptions or logical errors that inflated the estimated benefit from the offset. After modifying the calculations to align with best practice guidance, we found only two of the 14 projects were likely to fully offset their impacts on koalas (average 55% of impact offset). The most common issues were overestimated benefits from averted losses and double‐counting of benefits. We conclude transparency around offset requirements is generally poor, and most biodiversity offsets for koalas are unlikely to fully counterbalance losses. Despite sound, long‐established policy, poor implementation means that even offsets for impacts on a highly valued species, for which offsets are ecologically plausible, are prone to failure. [ABSTRACT FROM AUTHOR]

Context: The unprecedented scale and severity of the 2019–2020 'Black Summer' bushfires in Australia were an environmental disaster, and koalas became the public face of the fires' toll on wildlife. Aims: We investigated the media stories on koalas during the fires to identify what was reported, and how the numbers of koalas killed by the fires were sourced and reported. Methods: We searched for media articles published in major Australian print and online news outlets, local sources, press releases and international outlets for the terms 'koala', 'fire', 'bushfire', 'emergency', 'disaster' and 'burn', published between 15 October 2019 and 31 October 2020, and recorded any numbers of koalas given in those reports. This places our methods in a qualitative realm of investigation. Key results: We reviewed 371 media articles on the bushfires and koalas in New South Wales (NSW). Almost half included an estimate of the numbers of koalas killed in NSW. Almost a third stated that koalas are going extinct in NSW, however almost two thirds did not mention that koalas were already in decline from threats other than fire. Conclusions: We concluded that it was dangerous to put numbers on koalas. Misinformation, half-truths, and neglecting the important role of science and scientists, can erode public trust in the media and in science. Implications: The obsession with numbers has left a legacy that can drown out the more considered narrative of science and lead to distortions of policy and management, as well as distract from other critical attributes of koala conservation. We reviewed 371 media articles on the bushfires and koalas in New South Wales published between September 2019 and October 2020 for a qualitative analysis of impacts, factual errors and misinformation, themes and imagery. Presentation of exaggerated figures obscured the complexity of the issues. We concluded that to put numbers on koalas killed and the New South Wales koala population can be misleading as it erodes public trust in media and distorts scientific facts. [ABSTRACT FROM AUTHOR]

Abstract Background Wildfires can have complex effects on wildlife populations. Understanding how post-fire conditions affect the movement ecology of threatened species can assist in better conservation and management, including informing the release of rescued and rehabilitated animals. The 2019–2020 megafires in Australia resulted in thousands of animals coming into care due to injury or concerns over habitat degradation. This included hundreds of koalas (Phascolarctos cinereus), for which relatively little was known about how fire affected habitat suitability, or when rehabilitated animals could be returned to burnt areas. Methods We compared the movements of koalas across three experimental groups–non-rehabilitated koalas in burnt habitat, non-rehabilitated koalas in nearby unburnt habitat, and rehabilitated koalas returned to their rescue location in burnt habitat in New South Wales, Australia. We GPS-tracked 32 koalas for up to nine months and compared, across treatment groups, home ranges, mean nightly distance moved, the farthest distance moved from their release site and total displacement distance. Results We found no differences in koala movements and home range size between non-rehabilitated koalas in burnt and unburnt habitat. However, rehabilitated koalas moved farther from their release site, had larger displacement distances, and larger home ranges than non-rehabilitated individuals. Regardless of their experimental group, we also found that males moved further than females each night. Additionally, our resource selection analysis showed that, koalas preferred low and moderately burnt habitats over all other fire severity classes. Conclusions Experimental frameworks that incorporate “treatment” and “control” groups can help isolate disturbance effects on animal movements. Encouragingly, despite catastrophic wildfires, burnt woodlands provided adequate resources for koalas to persist and recover. Furthermore, rehabilitated koalas re-integrated into the burnt landscape despite moving farther from their release sites than non-rehabilitated individuals. Studies like this improve our understanding of the ecological impacts of fire on species and their habitats, and will be instrumental in informing wildlife management and conservation efforts as wildfires increase in frequency and severity worldwide in response to climate change.

Abstract Biodiversity offsets are a popular policy tool for mitigating the impact of development on biodiversity, but the ecological success of offsets arise from complex interactions among socio‐economic, ecological and policy processes, making outcomes challenging to assess. Many offset policies use habitat surrogates to determine offset requirements, rather than using direct measures of impacted biota, and this can lead to poor outcomes for species. One potential solution to this is for offsets to be delivered by a public agency (agency‐led) rather than by developers (developer‐led). This is because agencies may be able to strategically choose offset sites that maximise outcomes for species (e.g. abundance), while there may be little reason for developers to act strategically in this way when offset requirements are based purely on habitat surrogates. Yet, the success of a strategic agency‐led approach is likely to depend on patterns of development and offset site availability. To examine this, we developed a novel integrated spatially explicit model of land‐use change, habitat, species abundance and offset regulation. We apply the model to the Queensland Government's Environmental Offsets Policy for koalas Phascolarctos cinereus in South East Queensland, Australia, and test how patterns of development and offset site availability influence the performance of agency‐led versus developer‐led offsets. When potential offset sites were plentiful, agency‐led offsets tended to outperform developer‐led offset delivery for maximising koala abundance while achieving similar or better outcomes for habitat area. Yet, when potential offset sites were rare, the relative performance of agency‐led offset was often poor, and offset requirements for habitat area were less likely to be met. Different spatial patterns of development had little effect on the relative performance of agency‐led versus developer‐led offsets. Our analysis shows that agency‐led offsets with strategic choices of offset sites can improve species' outcomes for habitat‐based offsets but can also risk failing to meet habitat area requirements when the availability of offset sites is low. Importantly, our integrated spatial model provides a holistic approach to assessing policy options for biodiversity offsets in dynamic human‐modified landscapes. Read the free Plain Language Summary for this article on the Journal blog.

Introduction: This study employs bulk RNA sequencing, PCR, and ELISA assays to analyze the pathological factors affecting the outcomes of C. pecorum ocular infections in koalas. It investigates the immune responses and gene expression profiles associated with various stages of koala ocular chlamydiosis. Methods: A cohort of 114 koalas from Queensland, Australia were assessed, with 47% displaying clinical signs of ocular disease. Animals were classified into three cohorts: acute active disease (G1), chronic active disease (G2), and chronic inactive disease (G3), along with subclinical Chlamydia pecorum positive (H2) and healthy (H1) cohorts. Results: Analysis of clinical, microbiological, humoral immune and cellular immune biomarkers revealed varying chlamydial loads and anti-chlamydial IgG levels across disease grades, with a negative correlation observed between ocular chlamydial load and anti-chlamydial IgG. Koala ocular mucosa gene expression analysis from 27 koalas identified shared expression pathways across disease cohorts, with a significant upregulation of IFNγ expression and tryptophan metabolism in all disease stages. Discussion: These findings help elucidate immune response dynamics and molecular pathways underlying koala ocular chlamydiosis, providing insights crucial for disease management strategies. [ABSTRACT FROM AUTHOR]

Infection by retroviruses and the mobilization of transposable elements cause DNA damage that can be catastrophic for a cell. If the cell survives, the mutations generated by retrotransposition may confer a selective advantage, although, more commonly, the effect of new integrants is neutral or detrimental. If retrotransposition occurs in gametes or in the early embryo, it introduces genetic modifications that can be transmitted to the progeny and may become fixed in the germline of that species. PIWI-interacting RNAs (piRNAs) are single-stranded, 21–35 nucleotide RNAs generated by the PIWI clade of Argonaute proteins that maintain the integrity of the animal germline by silencing transposons. The sequence specific manner by which piRNAs and germline-encoded PIWI proteins repress transposons is reminiscent of CRISPR, which retains memory for invading pathogen sequences. piRNAs are processed preferentially from the unspliced transcripts of piRNA clusters. Via complementary base pairing, mature antisense piRNAs guide the PIWI clade of Argonaute proteins to transposon RNAs for degradation. Moreover, these piRNA-loaded PIWI proteins are imported into the nucleus to modulate the co-transcriptional repression of transposons by initiating histone and DNA methylation. How retroviruses that invade germ cells are first recognized as foreign by the piRNA machinery, as well as how endogenous piRNA clusters targeting the sequences of invasive genetic elements are acquired, is not known. Currently, koalas (Phascolarctos cinereus) are going through an epidemic due to the horizontal and vertical transmission of the KoRV-A gammaretrovirus. This provides an unprecedented opportunity to study how an exogenous retrovirus becomes fixed in the genome of its host, and how piRNAs targeting this retrovirus are generated in germ cells of the infected animal. Initial experiments have shown that the unspliced transcript from KoRV-A proviruses in koala testes, but not the spliced KoRV-A transcript, is directly processed into sense-strand piRNAs. The cleavage of unspliced sense-strand transcripts is thought to serve as an initial innate defense until antisense piRNAs are generated and an adaptive KoRV-A-specific genome immune response is established. Further research is expected to determine how the piRNA machinery recognizes a new foreign genetic invader, how it distinguishes between spliced and unspliced transcripts, and how a mature genome immune response is established, with both sense and antisense piRNAs and the methylation of histones and DNA at the provirus promoter. [ABSTRACT FROM AUTHOR]

Curbing global wildlife population declines will necessitate the protection of their habitat, and subsequent robust baseline information about wildlife that use and occupy it. Collating such information, however, remains a challenging and costly endeavour. Little did we know that traces of wildlife presence float in the air and can be detected through traces of DNA.Here, we deployed samplers to test the applicability of collecting airborne eDNA for the detection of a threatened species, the koala, and its co‐occurring terrestrial mammalian community.We develop a novel species specific qPCR assay to detect the presence of koalas and applied this in concert with a meta‐barcoding approach to detect the co‐occurring mammalian community.Through sampling of airborne particles, we successfully detected koala presence accurately to habitat patch level, alongside 16 unique taxonomic assignments, successfully assigning 11 of these to species level including detections belonging to the wallaby, antechinus, members of possum family and invasive species such as foxes, domestic dogs and hares.Synthesis and applications: We demonstrate the potential of airborne eDNA for the detection of threatened terrestrial wildlife and their surrounding ecological community under natural conditions. With achievable optimisations we detail how airborne eDNA may be applied for the management and monitoring of threated species for enhanced conservation efforts. [ABSTRACT FROM AUTHOR]

Effective detection techniques are important for wildlife monitoring and conservation applications and are especially helpful for species that live in complex environments, such as arboreal animals like koalas (Phascolarctos cinereus). The implementation of infrared cameras and drones has demonstrated encouraging outcomes, regardless of whether the detection was performed by human observers or automated algorithms. In the case of koala detection in eucalyptus plantations, there is a risk to spotters during forestry operations. In addition, fatigue and tedium associated with the difficult and repetitive task of checking every tree means automated detection options are particularly desirable. However, obtaining high detection rates with minimal false alarms remains a challenging task, particularly when there is low contrast between the animals and their surroundings. Koalas are also small and often partially or fully occluded by canopy, tree stems, or branches, or the background is highly complex. Biologically inspired vision systems are known for their superior ability in suppressing clutter and enhancing the contrast of dim objects of interest against their surroundings. This paper introduces a biologically inspired detection algorithm to locate koalas in eucalyptus plantations and evaluates its performance against ten other detection techniques, including both image processing and neural-network-based approaches. The nature of koala occlusion by canopy cover in these plantations was also examined using a combination of simulated and real data. The results show that the biologically inspired approach significantly outperformed the competing neural-network- and computer-vision-based approaches by over 27%. The analysis of simulated and real data shows that koala occlusion by tree stems and canopy can have a significant impact on the potential detection of koalas, with koalas being fully occluded in up to 40% of images in which koalas were known to be present. Our analysis shows the koala's heat signature is more likely to be occluded when it is close to the centre of the image (i.e., it is directly under a drone) and less likely to be occluded off the zenith. This has implications for flight considerations. This paper also describes a new accurate ground-truth dataset of aerial high-dynamic-range infrared imagery containing instances of koala heat signatures. This dataset is made publicly available to support the research community. [ABSTRACT FROM AUTHOR]

Habitat loss due to wildfire is an increasing problem internationally for threatened animal species, particularly tree-dependent and arboreal animals. The koala (Phascolartos cinereus) is endangered in most of its range, and large areas of forest were burnt by widespread wildfires in Australia in 2019/2020, mostly areas dominated by eucalypts, which provide koala habitats. We studied the impact of fire and three subsequent years of recovery on a property in South-East Queensland, Australia. A classified Differenced Normalised Burn Ratio (dNBR) calculated from pre- and post-burn Sentinel-2 scenes encompassing the local study area was used to assess regional impact of fire on koala-habitat forest types. The geometrically structured composite burn index (GeoCBI), a field-based assessment, was used to classify fire severity impact. To detect lower levels of forest recovery, a manual classification of the multitemporal dNBR was used, enabling the direct comparison of images between recovery years. In our regional study area, the most suitable koala habitat occupied only about 2%, and about 10% of that was burnt by wildfire. From the five koala habitat forest types studied, one upland type was burnt more severely and extensively than the others but recovered vigorously after the first year, reaching the same extent of recovery as the other forest types. The two alluvial forest types showed a negligible fire impact, likely due to their sheltered locations. In the second year, all the impacted forest types studied showed further, almost equal, recovery. In the third year of recovery, there was almost no detectable change and therefore no more notable vegetative growth. Our field data revealed that the dNBR can probably only measure the general vegetation present and not tree recovery via epicormic shooting and coppicing. Eucalypt foliage growth is a critical resource for the koala, so field verification seems necessary unless more-accurate remote sensing methods such as hyperspectral imagery can be implemented. [ABSTRACT FROM AUTHOR]

Background: Koala retrovirus (KoRV), a major pathogen of koalas, exists in both endogenous (KoRV-A) and exogenous forms (KoRV-A to I and K to M) and causes multiple disease phenotypes, including carcinomas and immunosuppression. However, the direct association between the different KoRV subtypes and carcinogenesis remains unknown. Differentially expressed gene (DEG) analysis of peripheral blood mononuclear cells (PBMCs) of koalas carrying both endogenous (KoRV-A) and exogenous (KoRV-A, B, and C) subtypes was performed using a high-throughput RNA-seq approach. PBMCs were obtained from three healthy koalas: one infected with endogenous (KoRV-A; Group I) and two infected with exogenous (KoRV-B and/or KoRV-C; Group II) subtypes. Additionally, spleen samples (n = 6) from six KoRV-infected deceased koalas (K1- K6) and blood samples (n = 1) from a live koala (K7) were collected and examined to validate the findings. Results: All koalas were positive for the endogenous KoRV-A subtype, and eight koalas were positive for KoRV-B and/or KoRV-C. Transcription of KoRV gag, pol, and env genes was detected in all koalas. Upregulation of cytokine and immunosuppressive genes was observed in koalas infected with KoRV-B or KoRV-B and -C subtypes, compared to koalas infected with only KoRV-A. We found 550 DEG signatures with significant (absolute p < 0.05, and absolute log2 Fold Change (FC) > 1.5) dysregulation, out of which 77.6% and 22.4% DEGs were upregulated (log2FC > 1.5) and downregulated (log2FC < − 1.5), and downregulated (log2 FC < − 1), respectively. We identified 17 unique hub genes (82.3% upregulated and 17.7% down-regulated), with KIF23, CCNB2, POLR3F, and RSL24D1 detected as the potential hub genes modified with KoRV infection. Real-time RT-qPCR was performed on seven koalas to ascertain the expression levels of four potential hub genes, which were subsequently normalized to actin copies. Notably, all seven koalas exhibited distinct expression signatures for the hub genes, especially, KIF23 and CCNB2 show the highest expression in healthy koala PBMC, and POLR3F shows the highest expression in koala with lymphoma (K1). Conclusion: Thus, it can be concluded that multiple KoRV subtypes affect disease progression in koalas and that the predicted hub genes could be promising prognostic biomarkers for pathogenesis. [ABSTRACT FROM AUTHOR]

The article discusses the KOALa student lab program, which aims to raise awareness about ocean acidification and promote responsible resource management. The program uses a mystery-based approach to engage students in scientific inquiry and includes a model experiment to explore the effects of burning fossil fuels on ocean chemistry. The article provides insights into the program's methodology, concept, and implementation, as well as initial findings from accompanying research. The goal is to provide practical suggestions for teachers to incorporate the topic of ocean acidification into their lessons using the mystery method and experiment-based ocean design proposals. The text also describes a model experiment that investigates the direct impact of combustion reactions in the atmosphere on ocean water and the resulting pH change. The experiment involves the use of beakers filled with water and a pH indicator, as well as the combustion of candles and the use of an aquarium pump. The results of the experiment demonstrate the decrease in pH and the color change of the solution, simulating the effects of increased carbon dioxide emissions on ocean acidification. The text also discusses the limitations of the model experiment and the importance of integrating visits to science laboratories into classroom instruction to promote student interest in STEM subjects. [Extracted from the article]

Simple Summary: After losing their habitat or having it broken up by infrastructure developments, one of the major threats to wild koalas is being hit by cars. Researchers analysed data for 345 koalas that were hit by cars on a 51 km section of the Peak Downs Highway in Queensland, Australia, from October 2014 to November 2023. We found that the spatial distribution of these accidents fit a random pattern along this stretch of road. Two factors seemed to predict where koalas might get hit: the amount of high-quality koala habitat nearby as defined by the local koalas' tree species preference, and driver visibility along the road. Because the landscape is relatively uniform in terms of landuse and vegetation, koalas can, and do, cross anywhere. More research, including detailed habitat mapping using geographic information systems and ground-truthing, is needed to help protect this important koala population and reduce the number of koala vehicle collisions and associated injury and mortality. After the loss and fragmentation of habitat, vehicle collisions are one of the main threats to the long-term survival of wild koalas. Koala road strike data were analysed for a section of the Peak Downs Highway between Nebo and Spencer's Gap, west of Mackay, Queensland, Australia. The analysis was carried out on 345 records (October 2014 to November 2023), and results suggested the spatial distribution of koala road strike followed a random pattern along this section of the highway, assuming a Poisson point pattern on a linear network. An analysis of the candidate predictors of koala vehicle collisions, including habitat and road variables, found that the amount of high-quality koala habitat (as defined by the local koalas' tree species preference) present and the driver visibility were the only significant predictors. The relative homogeneity of landuse and vegetation across this landscape may mean that koalas do not concentrate at specific crossing points. More research, including detailed habitat mapping, is needed into this population, which currently lacks government and conservation attention, to inform mitigation efforts and reduce mortality rates for this potentially nationally significant population. [ABSTRACT FROM AUTHOR]

Q fever is a zoonosis caused by Coxiella burnetii, primarily affecting those in close contact with domestic ruminants, the main source of human infection. Coxiella burnetii has also been detected in various wildlife species globally. In Australia, serological and molecular studies have shown exposure to and infection by C. burnetii in macropods, bandicoots, and koalas. However, the extent to which these species contribute to human infection remains unclear. An unpublished public health investigation into a Q fever case in a person involved in koala care could not conclusively link the infection to koalas due to the patient's broad animal exposure. This study aimed to explore the potential role of koalas in transmitting C. burnetii to humans by investigating the presence of C. burnetii DNA in urogenital tract (UGT) swabs from koalas. DNA was extracted from UGT swabs from koalas in three regions in New South Wales, Australia. An optimised multiplex qPCR assay detected C. burnetii DNA in 2 out of 225 samples (0.89%) at approximately 10 genome equivalents per reaction. Both positive samples amplified all three gene targets. MLVA genotyping identified two distinct C. burnetii genotypes previously isolated from Australian Q fever cases. These findings highlight the need for vaccination against Q fever for those in close contact with koalas. [ABSTRACT FROM AUTHOR]

Biodiversity offsets are a popular policy tool for mitigating the impact of development on biodiversity, but the ecological success of offsets arise from complex interactions among socio‐economic, ecological and policy processes, making outcomes challenging to assess.Many offset policies use habitat surrogates to determine offset requirements, rather than using direct measures of impacted biota, and this can lead to poor outcomes for species. One potential solution to this is for offsets to be delivered by a public agency (agency‐led) rather than by developers (developer‐led). This is because agencies may be able to strategically choose offset sites that maximise outcomes for species (e.g. abundance), while there may be little reason for developers to act strategically in this way when offset requirements are based purely on habitat surrogates. Yet, the success of a strategic agency‐led approach is likely to depend on patterns of development and offset site availability.To examine this, we developed a novel integrated spatially explicit model of land‐use change, habitat, species abundance and offset regulation. We apply the model to the Queensland Government's Environmental Offsets Policy for koalas Phascolarctos cinereus in South East Queensland, Australia, and test how patterns of development and offset site availability influence the performance of agency‐led versus developer‐led offsets.When potential offset sites were plentiful, agency‐led offsets tended to outperform developer‐led offset delivery for maximising koala abundance while achieving similar or better outcomes for habitat area. Yet, when potential offset sites were rare, the relative performance of agency‐led offset was often poor, and offset requirements for habitat area were less likely to be met. Different spatial patterns of development had little effect on the relative performance of agency‐led versus developer‐led offsets.Our analysis shows that agency‐led offsets with strategic choices of offset sites can improve species' outcomes for habitat‐based offsets but can also risk failing to meet habitat area requirements when the availability of offset sites is low. Importantly, our integrated spatial model provides a holistic approach to assessing policy options for biodiversity offsets in dynamic human‐modified landscapes. Read the free Plain Language Summary for this article on the Journal blog. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Simple Summary: Chlamydial infections are a major threat to the health of koalas (Phascolarctos cinereus), an iconic Australian marsupial. Among the different chlamydial species, Chlamydia pecorum (C. pecorum) is the major pathogen infecting koalas, affecting their health and long-term survival, both in the wild and in captivity. Therefore, a deeper understanding of chlamydial infections, including their epidemiology, transmission mode, pathogenesis, host immune response, control, and prevention, is critical for the management of chlamydial infections in koalas. Herein, we discuss the current literature on C. pecorum infection in koalas, including the epidemiology, transmission, pathogenesis, immune response, and control strategies for chlamydial infection, with the aim of improving koala health and achieving effective conservation strategies. Chlamydial infections pose a significant threat to koala populations. Chlamydia pecorum (C. pecorum) remains the major chlamydial species affecting koala health, both in the wild and in captivity, and chlamydial infections are considered important factors affecting the long-term survival of koalas. A clear understanding of chlamydial infections, including the epidemiology, transmission mode, pathogenesis, immune response, control, and prevention thereof, is essential for improving the management of chlamydial infections in koalas. In this study, we discuss the important advances made in our understanding of C. pecorum infection in koalas, focusing on the epidemiology of chlamydial infections, and the transmission, pathogenesis, immune response, and control strategies for chlamydial infection, with the aim of improving koala health and achieving effective conservation strategies. [ABSTRACT FROM AUTHOR]

Populations of Queensland koalas are rapidly declining, and the driving force behind this is habitat loss. This study analyzed reports (N = 50,858) made to three wildlife- focused veterinary clinics within the South-East Queensland Wildlife Hospital Network for assistance relating to a sick or injured wild koala between 1997 and 2019. Using descriptive and inferential statistics, a nominal logistic regression was performed to test the effect of key independent variables (age, sex, and etiology) on the outcome of each koala (released, deceased, euthanized) after being reported. Results found that the most common outcome for both sexes, most etiologies, and all ages was euthanasia. A comprehensive understanding of the primary risks affecting endangered species, and how these risks affect the likelihood of survival, is essential to inform species conservation policies and extinction risk assessments. We hope this study can provide an indispensable basis for future koala conservation strategies. [ABSTRACT FROM AUTHOR]

Koala (Phascolarctos cinereus) joey rescues are increasing over the past decade, and rehabilitation of a joey requires extensive care, and close proximity and handling by humans. These novel environments are likely to present a suite of biotic and abiotic stressors during rehabilitation. In this study, we aimed to monitor the physiological response of orphaned koala joeys to potential stressors. A total of 92 faecal samples were analysed for faecal cortisol metabolites (FCMs) using a polyclonal R4866 cortisol enzyme-immunoassay which has been previously validated in koalas. The iterative baseline method was used to establish FCM profiles of all individuals, and to identify significant peaks in FCM concentrations. Visitor events were identified and confirmed as an acute stressor based on the FCM profiles of the koala joeys. All koala joeys were found to have a significant rise in FCM concentrations after each visitor encounter. These results provide the first record of acute stress response of koala joeys to visitors. We suggest that visitor encounters be kept to a minimum and perhaps avoided altogether, especially for young rehabilitating joeys. [ABSTRACT FROM AUTHOR]

Climate change has altered the frequency and severity of extreme weather, which can affect vegetation condition and habitat quality for wildlife. Declines in vegetation productivity during droughts and heatwaves can negatively impact animals that depend on vegetation for water and nutrition. We used the normalised difference vegetation index (NDVI) to look at relationships between vegetation productivity and the presence of koalas (Phascolarctos cinereus) in potential habitat throughout much of their range. Using a large, long-term koala presence dataset, we tested the hypothesis that locations where koalas had been observed would exhibit higher NDVI values than a random, representative sample from the same vegetation group. We also identified the minimum NDVI threshold at which koalas occurred across time for each vegetation group and compared these to the minimum NDVI values across potential koala habitat before and during the Millennium Drought, one of the worst recorded in Australia. Additionally, we investigated whether vegetation above the minimum NDVI thresholds was significantly closer to perennial water than unsuitable vegetation. We found that koalas tend to occur at locations with higher NDVI than average for all vegetation groups. Prior to the drought, 49% of potential koala habitat maintained a minimum NDVI above the koalas' threshold, equating to 190,227 km2, which declined to 166,746 km2 during drought (i.e., a 12% reduction). We also found that unsuitable vegetation tended to occur farther from perennial water than suitable vegetation for some vegetation groups. Areas that remained above the NDVI thresholds during the drought should be considered potential refugia for populations during an event of similar magnitude and could indicate future habitat extent. [ABSTRACT FROM AUTHOR]

Sarcoptic mange (etiological agent Sarcoptes scabiei) is among the most important parasitic diseases of some marsupial species and has been an emerging disease of koalas, causing welfare and conservation implications. Fluralaner (Bravecto® MSD Animal Health), an ectoparasiticide of the isoxazoline class, has been demonstrated as a long-lasting and efficacious chemotherapeutic agent against sarcoptic mange in multiple mammal species and may also be beneficial for impacted koalas. Here, we evaluated the pharmacokinetics and clinical safety of fluralaner in koalas. Healthy captive individuals were treated topically with 85 mg/kg fluralaner administered to the interscapular epidermis. Following treatment, fluralaner was detected in plasma using ultra-performance liquid chromatography and tandem mass-spectrometry over a 12-week period. The mean maximum plasma concentration (Cmax) was 66.4 ng/mL; mean time was Cmax of 2.71 days; plasma elimination half-life (T1/2) was 30.91 days; and mean residence time (MRT) was 27.38 days. Haematological, blood biochemical, animal husbandry and clinical observations, over the same time period, demonstrated fluralaner was well tolerated. Overall, this research suggests fluralaner is a safe and long-lasting chemotherapeutic agent that may be efficacious against S. scabiei in koalas. Further research focussed on quantifying efficacy in captive and field settings, and across a range of disease severities would be valuable.

In 2022, the Australian Government listed the koala as endangered in several states due to habitat destruction, traffic strikes, dog attacks, and Chlamydia pecorum disease. This study evaluates a 10-year assessment of a Major Outer Membrane Protein-based vaccine's effectiveness against chlamydial disease in wild koalas from Southeast Queensland. Over a decade, 680 koalas were tracked, with five vaccine trials involving 165 koalas. While prior studies only offered up to two years of data, this study's extended period allowed a thorough evaluation of vaccine efficacy. Results showed that vaccinated koalas had significantly lower disease incidence, with a 64% reduction in chlamydial mortality. This vaccine demonstrated positive impacts on both male and female koalas, highlighting its crucial role in conserving the Australian koala population and mitigating the threats they face. [ABSTRACT FROM AUTHOR]

Large‐scale ecological restoration is a crucial tool for improving the quality and extent of habitat for wildlife. In Australia, 25,000 hectares of land is to be restored to support habitat connectivity for the Endangered koala (Phascolarctos cinereus). However, limited funding is a barrier to achieving restoration of this scale without the integration of new technologies and approaches. Seed enhancement technologies (SETs) are commonly used in agriculture to improve plant establishment and growth while reducing seed wastage; yet SETs are rarely used in restoration. Here, we tested the efficacy of SETs with five native tree species favored by koalas. Using a greenhouse trial, we measured emergence, time to emergence, growth rates, and survival up to 7 weeks post planting. At 33 weeks post‐planting, we measured total biomass, root: shoot ratios, and the specific root length. SETs resulted in comparable emergence and survival and promoted a longer time to emergence relative to bare seeds. Importantly, seedlings grown from SETs yielded higher average growth rates (0.3 mm/week higher), total biomass (5.93 mg higher) and root: shoot ratios (0.258 higher) relative to seedlings grown without SETs. These findings underscore the applicability of SETs to native species to support large‐scale koala habitat restoration by increasing the growth rate and size of seedlings at the early life stage. [ABSTRACT FROM AUTHOR]

Genetic management is a critical component of threatened species conservation. Understanding spatial patterns of genetic diversity is essential for evaluating the resilience of fragmented populations to accelerating anthropogenic threats. Nowhere is this more relevant than on the Australian continent, which is experiencing an ongoing loss of biodiversity that exceeds any other developed nation. Using a proprietary genome complexity reduction‐based method (DArTSeq), we generated a data set of 3239 high quality Single Nucleotide Polymorphisms (SNPs) to investigate spatial patterns and indices of genetic diversity in the koala (Phascolarctos cinereus), a highly specialised folivorous marsupial that is experiencing rapid and widespread population declines across much of its former range. Our findings demonstrate that current management divisions across the state of New South Wales (NSW) do not fully represent the distribution of genetic diversity among extant koala populations, and that care must be taken to ensure that translocation paradigms based on these frameworks do not inadvertently restrict gene flow between populations and regions that were historically interconnected. We also recommend that koala populations should be prioritised for conservation action based on the scale and severity of the threatening processes that they are currently faced with, rather than placing too much emphasis on their perceived value (e.g., as reservoirs of potentially adaptive alleles), as our data indicate that existing genetic variation in koalas is primarily partitioned among individual animals. As such, the extirpation of koalas from any part of their range represents a potentially critical reduction of genetic diversity for this iconic Australian species. [ABSTRACT FROM AUTHOR]

Retroviruses are an ancient viral family that have globally coevolved with vertebrates and impacted their evolution. In Australia, a continent that has been geographically isolated for millions of years, little is known about retroviruses in wildlife, despite the devastating impacts of a retrovirus on endangered koala populations. We therefore sought to identify and characterize Australian retroviruses through reconstruction of endogenous retroviruses from marsupial genomes, in particular the Tasmanian devil due to its high cancer incidence. We screened 19 marsupial genomes and identified over 80,000 endogenous retrovirus fragments which we classified into eight retrovirus clades. The retroviruses were similar to either Betaretrovirus (5/8) or Gammaretrovirus (3/8) retroviruses, but formed distinct phylogenetic clades compared to extant retroviruses. One of the clades (MEBrv 3) lost an envelope but retained retrotranspositional activity, subsequently amplifying throughout all Dasyuridae genomes. Overall, we provide insights into Australian retrovirus evolution and identify a highly active endogenous retrovirus within Dasyuridae genomes. [ABSTRACT FROM AUTHOR]

In July 1927, the Queensland state government declared an open season on koalas, in which more than 600,000 koalas were shot, poisoned, or trapped. In the broad-based and emotional backlash which ensued, gender ideologies featured significantly. Concepts of authentically Australian forms of masculinity and femininity were mobilised in attempts to end the destruction; koala-killing was framed as a debasement of an idealised ‘bushman’ identity and koala fur wearing as a betrayal of an idealised category of inherently caring womanhood. The interests of parents and children came to the fore in a campaign concerned with preserving the popular ‘native bear’ for the enjoyment of future generations. This article draws out how gendered understandings of koalas and koala-killing contributed to the animals’ reclassification from an economic resource to an anthropomorphised friend and symbol, whose slaughter was conceived by many as unmanly and un-Australian. [ABSTRACT FROM AUTHOR]

Simple Summary: This review reports on the current and potential utility of the "koala scat" sample to provide a range of ecological and physiological assessments both at the population and individual animal level and do so in a non-invasive manner. DNA recovered from the scat sample provides useful information on koala distribution, diet, genetics and disease, whereas hormone metabolites can inform physiology. While there are still limitations with respect to the decay of quality DNA (host, microbiome, and pathogen) over time related to climate and sample handling, some of these issues can be overcome with timely sample collection. Other current limitations include an inability to detect and quantify particular hormone metabolites such as oestrogens and/or an appropriate biological interpretation of glucocorticoid metabolite secretion when measured in the faecal sample. The use of samples or scats to provide important ecological, genetic, disease and physiology details on free-range populations is gaining popularity as an alternative non-invasive methodology. Koala populations in SE Queensland and NSW have recently been listed as endangered and continue to face anthropomorphic and stochastic environmental impacts that could potentially lead to their extinction. This scoping review examines the current and potential utility of the koala scat to contribute data relevant to the assessment of koala conservation status and decision making. Although we demonstrate that there is great potential for this methodology in providing details for both individual wild animal and population biology (distribution, abundance, sex ratio, immigration/emigration, genetic diversity, evolutionary significant unit, disease epidemiology, nutrition, reproductive status and stress physiology), the calibre of this information is likely to be a function of the quality of the scat that is sampled. [ABSTRACT FROM AUTHOR]

Quantifying the cost‐effectiveness of alternative sampling methods is crucial for efficient biodiversity monitoring and detection of population trends. In this study, we compared the cost‐effectiveness of three novel sampling methods for detecting changes in koala (Phascolarctos cinereus) occupancy: thermal drones, passive acoustic recorders and camera trapping. Specifically, we fitted single‐season occupancy‐detection models to data recorded from 46 sites in eight bioregions of New South Wales, Australia, between 2018 and 2022. We explored the effect of weather variables on daily detection probability for each method and, using these estimates, calculated the statistical power to detect 30%, 50% and 80% declines in koala occupancy. We calculated power for different combinations of sites (1–200) and repeat surveys (2–40) and developed a cost model that found the cheapest survey design that achieved 80% power to detect change. On average, detectability of koalas was highest with one 24‐h period of acoustic surveys (0.32, 95% CI's: 0.26, 0.39) compared to a 25‐ha flight of drone surveys (0.28, 95% 0.15, 0.48) or a 24‐h period of camera trapping consisting of six cameras (0.019, 95% CI's: 0.014, 0.025). We found a negative quadratic relationship between detection probability and air temperature for all three methods. Our power and cost analysis suggested that 148 sites surveyed with acoustic recorders deployed for 14 days would be the cheapest method to sufficiently detect a 30% decline in occupancy with 80% power. We recommend passive acoustic recorders as the most efficient sampling method for monitoring koala occupancy compared to cameras or drones. Further comparative studies are needed to compare the relative effectiveness of these methods and others when the monitoring objective is to detect change in koala abundance over time. [ABSTRACT FROM AUTHOR]

This study is the second in a series that examines the habitat requirements and response to logging of koalas (Phascolarctos cinereus) inhabiting tall eucalypt forests of north-east NSW. It presents the findings of koala population and habitat monitoring surveys in Pine Creek State Forest and Bongil Bongil National Park using a combination of call-counting and direct observation (spotlighting). The 6400 ha study area was mapped into 6 zones of increasing koala habitat quality by ground survey of forest structure and floristics on a 200 m grid. The accuracy of habitat definition and mapping was tested by stratified transect counts of koala calls and sightings over two consecutive years (1997–98). Average koala density increased steeply and significantly, from 0.02 – 0.20 koalas/hectare, with increasing mapped habitat quality based on increasing forest age, structural complexity, local food tree species diversity, history of prior koala occurrence and decreased past logging intensity. This relationship was driven primarily by breeding females, with the number of male koala calls weakly or uncorrelated with koala sightings and mapped habitat quality. Male koalas were more widely and uniformly distributed than females, including areas of low quality, plantation, and intensively logged forest. This finding explains the discrepancy between our results and those of other recent studies which concluded that koalas are tolerant of intensive logging based on modelling of calling male koalas and reliance on an untested assumption that male calling is indicative of female breeding success. Koala density in a subset of the highest quality habitat was relatively stable at 0.28 koalas/ha (3 hectares/koala) over the long term (1997–98 and 2012–2023). Key characteristics of the forest koala population, including low stable density, large home ranges, preference for high food tree diversity and locally unique food trees (including Allocasuarina torulosa and Syncarpia glomulifera), are not adequately explained by existing koala habitat models. We present a new paradigm to explain regional variation in koala distribution, habitat and foraging preferences based on variations in foliage chemistry (toxicity and nutritional value) determined by the duration and stability of local plant-koala interactions in response to past fire, hunting, predation and logging disturbance history. We hypothesize that koala density in stable forest populations is regulated at low levels by a combination of selected and induced increases in leaf toxicity and decreases in leaf nutrition that limit koala browsing to benign levels of about 1-2% of annual leaf production. Large home ranges, complex mature forest structure, high food tree diversity and a specialized or diverse gut microbiome may be essential to allow females to rotate and change food trees frequently to minimize induced toxicity and select individual leaves with sufficient nutrients to support breeding and lactation with minimal risk of predation. High density koala populations (> 0.6/ha) occur primarily in areas where koalas have been introduced or re-introduced to planted habitats and natural areas where aboriginal hunters and dingoes were historically present but are now absent, and where food trees have not been selected for resistance to koala browsing pressure. [ABSTRACT FROM AUTHOR]

Chlamydiosis is one of the main causes of the progressive decline of koala populations in eastern Australia. While histologic, immunologic, and molecular studies have provided insights into the basic function of the koala immune system, the in situ immune cell signatures during chlamydial infection of the reproductive tract in koalas have not been investigated. Thirty-two female koalas and 47 males presented to wildlife hospitals with clinical signs suggestive of Chlamydia infection were euthanized with the entire reproductive tract collected for histology; immunohistochemistry (IHC) for T-cell (CD3ε, CD4, and CD8α), B-cell (CD79b), and human leukocyte antigen (HLA)-DR markers; and quantitative real-time polymerase chain reaction (rtPCR) for Chlamydia pecorum. T-cells, B-cells, and HLA-DR-positive cells were observed in both the lower and upper reproductive tracts of male and female koalas with a statistically significant associations between the degree of the inflammatory reaction; the number of CD3, CD4, CD79b, and HLA-DR positive cells; and the PCR load. CD4-positive cells were negatively associated with the severity of the gross lesions. The distribution of immune cells was also variable according to the location within the genital tract in both male and female koalas. These preliminary results represent a step forward towards further exploring mechanisms behind chlamydial infection immunopathogenesis, thus providing valuable information about the immune response and infectious diseases in free-ranging koalas. [ABSTRACT FROM AUTHOR]

Cryptococcus is a genus of fungal pathogens that can infect and cause disease in a range of host species and is particularly prominent in koalas (Phascolarctos cinerus). Like other host species, koalas display a range of outcomes upon exposure to environmental Cryptococcus, from external nasal colonization to asymptomatic invasive infection and, in rare cases, severe clinical disease resulting in death. Host factors contributing to these varied outcomes are poorly understood. Due to their close relationship with eucalypt trees (a key environmental niche for Cryptococcus gattii) and suspected continual exposure to the pathogen, koalas provide a unique opportunity to examine host susceptibility in natural infections. Caspase recruitment domain-containing protein 9 (CARD9) is a key intracellular signaling protein in the fungal innate immune response. Humans with mutations in CARD9 succumb to several different severe and chronic fungal infections. This study is the first to sequence and explore CARD9 variation in multiple koalas using Sanger sequencing. Four CARD9 exons were successfully sequenced in 22 koalas from a New South Wales, Australia population. We found minimal variation between koalas across all four exons, an observation that was also made when CARD9 sequences were compared between koalas and six other species, including humans and mice. Ten single-nucleotide polymorphisms (SNP) were identified in this study and explored in the context of cryptococcal exposure outcomes. While we did not find any significant association with variation in cryptococcal outcomes, we found a high degree of conservation between species at several SNP loci that requires further investigation. The findings from this study lay the groundwork for further investigations of CARD9 and Cryptococcus both in koalas and other species, and highlight several considerations for future studies. [ABSTRACT FROM AUTHOR]

Environmental crises, such as wildfires, can cause major losses of human life, infrastructure, biodiversity, and cultural values. In many such situations, incident controllers must make fateful choices about what to protect—and hence what to abandon. With an online representative survey of >2000 adult Australians, we investigated social attitudes to this dilemma. We used best–worst scaling to assess preferences across a set of 11 assets representing human life, infrastructure, biodiversity, and cultural values. Survey respondents overwhelmingly prioritized a single human life (best–worst score of 6647 out of possible score ranging from −10695 to 10695), even if that choice resulted in extinction of other species. Inanimate (replaceable) objects were accorded lowest priority (best–worst scores of −4655 for a shed and −3242 for a house). Among biodiversity assets, respondents prioritized protecting a population of the iconic koala (Phascolarctos cinereus) (best–worst score of 1913) ahead of preventing the extinction of a snail (score −329) and a plant species (−226). These results variably support current policy in that they emphasize the importance the community places on protection of human life, but results diverged from conventional practice in rating some biodiversity assets ahead of infrastructure. The preference for protecting a population of koalas ahead of action taken to prevent the extinction of an invertebrate and plant species corroborates previous research reporting biases in the way people value nature. If noncharismatic species are not to be treated as expendable, then the case for preventing their extinction needs to be better made to the community. Given the increasing global incidence of high‐severity wildfires, further sampling of societal preferences among diverse asset types is needed to inform planning, policy, and practice relating to wildfire. Other preemptive targeted management actions (such as translocations) are needed to conserve biodiversity, especially noniconic species, likely to be imperiled by catastrophic events. [ABSTRACT FROM AUTHOR]

IntroductionThis study employs bulk RNA sequencing, PCR, and ELISA assays to analyze the pathological factors affecting the outcomes of C. pecorum ocular infections in koalas. It investigates the immune responses and gene expression profiles associated with various stages of koala ocular chlamydiosis.MethodsA cohort of 114 koalas from Queensland, Australia were assessed, with 47% displaying clinical signs of ocular disease. Animals were classified into three cohorts: acute active disease (G1), chronic active disease (G2), and chronic inactive disease (G3), along with subclinical Chlamydia pecorum positive (H2) and healthy (H1) cohorts.ResultsAnalysis of clinical, microbiological, humoral immune and cellular immune biomarkers revealed varying chlamydial loads and anti-chlamydial IgG levels across disease grades, with a negative correlation observed between ocular chlamydial load and anti-chlamydial IgG. Koala ocular mucosa gene expression analysis from 27 koalas identified shared expression pathways across disease cohorts, with a significant upregulation of IFNγ expression and tryptophan metabolism in all disease stages.DiscussionThese findings help elucidate immune response dynamics and molecular pathways underlying koala ocular chlamydiosis, providing insights crucial for disease management strategies.

Population trends are lacking for most threatened species, especially those that are cryptic and difficult to survey. Recent developments in passive acoustics and semi‐automated call recognition provide a cost‐effective option to systematically monitor populations of vocal species. We assessed recent trends for the koala Phascolarctos cinereus, an iconic marsupial, based on 7 years of acoustic monitoring across 224 forested sites. The study period overlapped with a severe drought and extensive megafires in 2019 followed by 2 years of extremely high rainfall. Dynamic occupancy modelling with a range of covariates at multiple landscape scales found that initial occupancy was related to elevation (−ve), NDVI (+ve) and previous selective harvesting (16–30‐year age class; weakly +ve). Extinction probability increased with the extent of high‐severity fire. Colonisation probability was related to a range of factors, with the top model showing a decrease with increasing lagged annual rainfall. However, the null model was also supported, suggesting weak associations for colonisation. Using these relationships, koala occupancy was found to be high and stable over the study period. Fire did not influence regional trends because koalas often persisted with low‐ to moderate‐severity fire and because high‐severity fire was limited to 11% of their habitat. In contrast, bellow rate varied across years, being initially low and declining immediately after the 2019 fires, with the driver of these changes unclear. Neither timber harvesting nor low‐severity fire influenced koala occupancy or bellow rate. Given the extensive area of koala habitat in the region, our results point to the presence of a large population in these public forests, and in recent years, stable occupancy (albeit with site‐scale reductions in density with high‐severity fire). Ongoing monitoring is crucial for tracking future changes, especially with predictions of more frequent, severe forest fires due to climate change. [ABSTRACT FROM AUTHOR]

Megafires can have a devastating effect on koala populations. With climate change increasing habitat vulnerability to wildfires, understanding how to efficiently measure the impact of these events on koalas is essential. We analysed the relationship between the 2019-2020 megafires and the probability of koala occurrence in Mid North Coast NSW. We found that two on-field and one satellite-derived variables measuring fire severity equally explained koala occurrence. The probability of koala occurrence decreased with increasing fire severity. This supports the use of remote sensing imagery to efficiently monitor the impact of future fire events on koala populations in the region. In the current context of climate change, megafires pose a severe threat to koala populations. Accurately assessing the impact of fire on a large scale is essential to provide an effective response to aid koala conservation. We found that satellite images were as effective as on-the-ground data in predicting post-fire koala occurrence in Mid North Coast NSW. Our results support the use of satellite-derived variables to efficiently monitor the fire impact on koala populations in the region. [ABSTRACT FROM AUTHOR]

Background: Koalas, an Australian arboreal marsupial, depend on eucalypt tree leaves for their diet. They selectively consume only a few of the hundreds of available eucalypt species. Since the koala gut microbiome is essential for the digestion and detoxification of eucalypts, their individual differences in the gut microbiome may lead to variations in their eucalypt selection and eucalypt metabolic capacity. However, research focusing on the relationship between the gut microbiome and differences in food preferences is very limited. We aimed to determine whether individual and regional differences exist in the gut microbiome of koalas as well as the mechanism by which these differences influence eucalypt selection. Methods: Foraging data were collected from six koalas and a total of 62 feces were collected from 15 koalas of two zoos in Japan. The mitochondrial phylogenetic analysis was conducted to estimate the mitochondrial maternal origin of each koala. In addition, the 16S-based gut microbiome of 15 koalas was analyzed to determine the composition and diversity of each koala's gut microbiome. We used these data to investigate the relationship among mitochondrial maternal origin, gut microbiome and eucalypt diet selection. Results and Discussion: This research revealed that diversity and composition of the gut microbiome and that eucalypt diet selection of koalas differs among regions. We also revealed that the gut microbiome alpha diversity was correlated with foraging diversity in koalas. These individual and regional differences would result from vertical (maternal) transmission of the gut microbiome and represent an intraspecific variation in koala foraging strategies. Further, we demonstrated that certain gut bacteria were strongly correlated with both mitochondrial maternal origin and eucalypt foraging patterns. Bacteria found to be associated with mitochondrial maternal origin included bacteria involved in fiber digestion and degradation of secondary metabolites, such as the families Rikenellaceae and Synergistaceae. These bacteria may cause differences in metabolic capacity between individual and regional koalas and influence their eucalypt selection. Conclusion: We showed that the characteristics (composition and diversity) of the gut microbiome and eucalypt diet selection of koalas differ by individuals and regional origins as we expected. In addition, some gut bacteria that could influence eucalypt foraging of koalas showed the relationships with both mitochondrial maternal origin and eucalypt foraging pattern. These differences in the gut microbiome between regional origins may make a difference in eucalypt selection. Given the importance of the gut microbiome to koalas foraging on eucalypts and their strong symbiotic relationship, future studies should focus on the symbiotic relationship and coevolution between koalas and the gut microbiome to understand individual and regional differences in eucalypt diet selection by koalas. [ABSTRACT FROM AUTHOR]

The pharmacokinetic profile of paracetamol in koalas is described when administered orally at 15 mg/kg; followed by the same dose, administered every 12 hours (hrs), repeated five times. After the initial oral administration, the median (range) maximal plasma concentration (Cmax), the time Cmax was reached (Tmax) and elimination half-life (t1/2) were 16.93 μg/mL (13.66 to 20.25 μg/mL); 4 hrs (4 to 8 hrs) and 5.54 hrs (4.66 to 7.67 hrs), respectively. When paracetamol was administered orally at 15 mg/mL every 12 hrs, the trough total plasma concentration range remained comparable to the therapeutic range in humans i.e. 4 to 20 μg/mL that is known to provide some analgesia. However, there is a smaller proportion of free drug (i.e. not bound to plasma proteins; and the active form) available in koala plasma (approximately 40% unbound) compared to human plasma (approximately 80% unbound). Consequently, even when there are similar total drug plasma concentrations in both koala and human plasma, the therapeutic efficacy may be reduced in koalas compared to humans. The initial oral dose and subsequent twice daily doses resulted in no obvious adverse effects in any koala. Haematology, plasma electrolyte and biochemical analyte values remained within their reference ranges eight hrs after the last dose but there was a significant change in alanine transaminase (ALT) levels (an increase), and in total protein (a decrease) (both p = 0.03). A dose of 15 mg/kg was also administered as a subcutaneous injection, diluted 50:50 with saline, to two koalas. As the oral formulation and the subcutaneous administration resulted in comparable absorption, the study focused on the oral profile. Based on these results there is an argument to recommend a slight increase in the oral paracetamol dose for the koala, however further investigation is required to confirm whether repeated administration of a slightly higher dose may be associated with more severe or additional significant changes in haematology, electrolytes or biochemical analytes. However, a preferable recommendation would be to administer this dosage of paracetamol in combination with another analgesic such as tramadol, as a subcutaneous injection, to improve efficacy. [ABSTRACT FROM AUTHOR]

An accurate picture of an animal's home range is fundamental for quantifying habitat quality and response to disturbance. When combined with remote sensing of vegetation attributes, there is potential to assess habitat selection at high resolution. We used a high‐quality GPS‐collaring data set (> 12 500 fixes) from 10 koalas Phascolarctos cinereus and a canopy height model derived from LiDAR in multiple‐use forests harvested for timber 5–10 years previously. Our aim was to assess how individual koalas use the forest mosaic created by timber harvesting by quantifying home ranges and habitat selection of different forest age/height classes created by past harvesting. We found that koalas maintained a stable home range over the average of 7 months of tracking. On average, there was 95% overlap for individuals among seasons, illustrating high site fidelity in the regenerating forest. Also, there were no apparent shifts during the intense drought of spring 2019. Male home ranges (64 ha) were three times the size of females (21 ha). Core areas were considerably smaller, ranging from 15 (male) to 6 ha (female). Three forest age/height classes were defined from LiDAR: (i) harvest – regeneration <14 m, (ii) harvest – retained trees ≥14 m and (iii) harvest – exclusion trees ≥14 m (zones excluded from harvesting for environmental protection). Home ranges covered the mosaic of forest classes and mixed models revealed no selection of forest class based on use versus availability. High site fidelity with no clear selection for forest age/height class (i.e. harvested and non‐harvested patches) confirms that resource quality in the home range remained sufficient for breeding koalas in the post‐harvest landscape. Ongoing monitoring of koalas is required to ensure that environmental protections are effective in maintaining koala populations in the face of additional disturbances from fire and climate change. [ABSTRACT FROM AUTHOR]

We provide a comparative analysis of two koala management plans for populations in two Australian municipalities, based on principles of landscape management: Ballarat (Victoria) and Bellingen (New South Wales). A landscape-based approach is required to protect the species, but evaluation of landscape management is limited. We present an assessment framework for evaluating local koala management plans. The plans are evaluated against a common set of principles and criteria, despite very different approaches stemming from context-specific factors. Interestingly, despite a variation in the number of indicators in the plans, the overall results of the evaluation demonstrate a similar level of performance against the criteria, and common strengths and weaknesses. In the absence of consistent standards for the protection of the koala across Australia, the species will continue to decline, and management practices will fail to protect the koala from extinction, as is currently predicted. [ABSTRACT FROM AUTHOR]

Simple Summary: The 2019–2020 Australian bushfire season had a devastating impact on native fauna. It was estimated that 3 billion animals were affected by the fires, but there are few accounts of the species or numbers of animals rescued and rehabilitated post-fire. We reviewed rescue, triage, rehabilitation and release reports for marsupials from two regions: the state of New South Wales (NSW) and Kangaroo Island, South Australia. In NSW, only 889 marsupial rescues were reported, despite estimates of 46.8 million marsupials inhabiting the fire zones. Three marsupial groups dominated the rescue statistics: kangaroos and wallabies (n = 458), koalas (n = 204), and possums (n = 162), with smaller numbers of other marsupial species. The probability of survival and release was lowest for kangaroos and wallabies (15% ± 4%) compared with koalas (47% ± 4%) and possums (55% ± 10%). Injury type was a significant predictor of survival for all groups, with malnourished/moribund animals or those with traumatic injuries less likely to survive. In both jurisdictions, koalas were over-represented, and possums under-represented, in rescue statistics relative to baseline population densities and pre-fire wildlife rescue trends. Triage decisions also varied by species, with koalas more likely to enter care, whereas other species were more likely to be euthanised at triage. Koalas were more likely to die during rehabilitation, with 73% dying or being euthanised between day 1 and 30 post-rescue, representing a potential welfare concern. These species differences in presentation post-fire warrant further investigation, as do the differences in triage, survival and release outcomes. These data highlight the need for detailed record keeping and data sharing, and the development of consistent and evidence-based triage, treatment and euthanasia guidelines for all species. The 2019–2020 Australian bushfire season had a devastating impact on native wildlife. It was estimated that 3 billion native animals were impacted by the fires, yet there are few estimates of the number of animals that were rescued and rehabilitated post-fire. Focusing on the state of New South Wales (NSW) and Kangaroo Island, South Australia, we used a case study approach to determine the number of marsupials that were reported rescued due to the 2019–2020 bushfires in these areas and analysed species-specific trends in rescue and release success. In NSW, we found 889 reports of fire-affected marsupials in 2019–2020, mostly comprising kangaroos and wallabies (macropods; n = 458), koalas (n = 204), and possums (n = 162), with a smaller number of wombats (n = 43) and other marsupial species. Most reports of fire-affected marsupials occurred 6–8 weeks after fire ignition, and there was no difference in temporal frequency of rescues between marsupial groups. For the three main groups, the probability of survival and subsequent release differed, with macropods having the lowest probability of release after rescue (0.15 ± 0.04) compared to koalas (0.47 ± 0.04) and possums (0.55 ± 0.10). The type of injury was the main predictor of survival during rehabilitation for all three marsupial groups, with those malnourished/moribund or with traumatic injuries less likely to survive rehabilitation. Death or euthanasia occurred on the day of rescue for 77% of macropods, 48% of possums and 15% of koalas. Koalas most often died during rehabilitation rather than on the day of rescue, with 73% either dying or being euthanised between day 1 and 30 post-rescue, representing a potential welfare concern. On Kangaroo Island, koalas were the most frequently rescued marsupial species; most euthanasia cases and deaths occurred in a hospital, whereas other marsupials were mostly euthanised at triage. In both jurisdictions, koalas were over-represented while possums were under-represented relative to baseline population densities and wildlife rescue trends in the years before the 2019–2020 bushfires. These species differences in presentation post-fire warrant further investigation, as do the differences in triage, survival and release outcomes. It is hypothesised that the high intensity and large scale of the 2019–2020 fires impeded marsupial fire evasion tactics, as evidenced by the small number of animals found for rescue, and the differing rates of presentation relative to underlying population densities for the main marsupial groups. Based on our findings, there is a need for detailed record keeping and data sharing, development of consistent and evidence-based triage, treatment and euthanasia guidelines and deployment of trained wildlife emergency rescue teams with advanced search techniques to minimise animal suffering where safe to do so. [ABSTRACT FROM AUTHOR]

External signs of disease are frequently used as indicators of disease susceptibility. However, immune profiling can be a more effective indicator to understand how host responses to infection may be shaped by host, pathogen and environmental factors. To better inform wildlife health assessment and research directions, we investigated the utility of a novel multivariate immunophenotyping approach examining innate and adaptive immune responses in differing climatic, pathogen co-infection and demographic contexts across two koala (Phascolarctos cinereus) populations in New South Wales: the Liverpool Plains (LP), and Southern Highlands to South-west Sydney (SHSWS). Relative to the comparatively healthy SHSWS, the LP had greater and more variable innate immune gene expression (IL-1β, IL-6), and KoRV transcription. During extreme heat and drought, koalas from the LP displayed upregulation of a stress pathway gene and reduced adaptive immune genes expression, haematocrit and plasma protein, suggesting the possibility of environmental impacts through multiple pathways. In those koalas, KoRV transcription status, Chlamydia pecorum infection loads, and visible urogenital inflammation were not associated with immune variation, suggesting that immune markers were more sensitive indicators of real-time impacts than observed disease outcomes. [ABSTRACT FROM AUTHOR]

Koalas (Phascolarctos cinereus) have experienced a history of retroviral epidemics leaving their trace as heritable endogenous retroviruses (ERVs) in their genomes. A recently identified ERV lineage, named phaCin-β, shows a pattern of recent, possibly current, activity with high insertional polymorphism in the population. Here, we investigate geographic patterns of three focal ERV lineages of increasing estimated ages, from the koala retrovirus (KoRV) to phaCin-β and to phaCin-β-like, using the whole-genome sequencing of 430 koalas from the Koala Genome Survey. Thousands of ERV loci were found across the population, with contrasting patterns of polymorphism. Northern individuals had thousands of KoRV integrations and hundreds of phaCin-β ERVs. In contrast, southern individuals had higher phaCin-β frequencies, possibly reflecting more recent activity and a founder effect. Overall, our findings suggest high ERV burden in koalas, reflecting historic retrovirus-host interactions. Importantly, the ERV catalogue supplies improved markers for conservation genetics in this endangered species. Insertional polymorphisms of recent endogenous retrovirus (ERV) lineages across the eastern koala populations reveal high ERV burden and contrasting geographical virus-host interaction patterns. [ABSTRACT FROM AUTHOR]