KOALA NEWS & SCIENCE
An informative monthly newsletter about successes & important announcements in koala conservation, and the latest scientific publications about koalas.
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A plan to vaccinate koalas against chlamydia 1 August
‘Queensland Great’ Prof Peter Timms of University of Sunshine Coast has a plan to vaccinate koalas via wildlife hospitals and relocation programs.
Senator Janet Rice joins local councillors to plant trees for koalas, VIC 21 July
The Federal Senator for Victoria, Councillors Sarah Mansfield & Belinda Moloney were among 100 volunteers to plant 8000 koala habitat trees at Balliang, Victoria. The project was funded by IFAW and City of Greater Geelong.
7000 signatures so far to save Sydney’s koalas NSW
A new petition started by Save Sydney’s Koalas calls on NSW Government to:
Declare an Upper Georges River Koala National Park, Stop the rezoning of Stage 2 of the Gilead development and review the approval of Stage 1 , Build five effective Koala crossings on Appin Road and Implement minimum 450m wide Koala corridors across the rivers and creeks of Macarthur
Protecting paddock trees 18 July
A new study from University of Sydney has shown the importance of isolated trees to koalas. Lone paddock trees may have foliage rich in nitrogen, which koalas will travel some distance to feed on.
Values and valuation of nature & biodiversity 30 June
Latest IPBES report calls on governments to understand and prioritise the many values of nature.
Community survey on attitudes to koalas around Toowoomba QLD 19 July
Griffith University have launched the second phase of their community study, and are looking to survey residents of Toowoomba & Darling Downs.
Zoo visitors raise $8,800 for koalas QLD 28 July
Visitors to the Rockhampton Zoo have collectively raised $8,800 for koala research. The donation will go to Koala Research CQ, part of CQ University.
Cristescu, R., Strickland, K., Schultz, A., Kruuk, L., de Villiers, D. and Frere, C., 2022. Susceptibility to a sexually-transmitted disease in a wild koala population shows heritable genetic variance but no inbreeding depression. Authorea Preprints.
The koala, one of the most iconic Australian wildlife species, is facing several concomitant threats that are driving population declines. Some threats are well known and have clear methods of prevention (e.g. habitat loss can be reduced with stronger land-clearing control), whereas others are less easily addressed. One of the major current threats to koalas is chlamydial disease, which can have major impacts on individual survival and reproduction rates, and can translate into population declines. Effective management strategies for the disease in the wild are currently lacking, and to date we know little about the determinants of individual susceptibility to disease. Here we used a rare opportunity to investigate the genetic basis of variation in susceptibility to chlamydia using one of the most intensively studied wild koala populations. We combine data from veterinary examinations, chlamydia testing, genetic sampling and movement monitoring. Out of our sample of 342 wild koalas, 60 were found to have chlamydia. Using genotype information on 8649 SNPs to investigate the role of genetic characteristics in determining disease status, we found no evidence of inbreeding depression, but a heritability of 0.14 (95%CI: 0.06 – 0.23) for the probability that koalas had chlamydia. Heritability of susceptibility to chlamydia could be relevant for future disease management in koalas, as it suggests the potential to select for disease resilience through assisted breeding.
Crowther, M.S., Rus, A.I., Mella, V.S., Krockenberger, M.B., Lindsay, J., Moore, B.D. and McArthur, C., 2022. Patch quality and habitat fragmentation shape the foraging patterns of a specialist folivore. Behav Ecol.
Research on use of foraging patches has focused on why herbivores visit or quit patches, yet little is known about visits to patches over time. Food quality, as reflected by higher nutritional quality and lower plant defenses, and physical patch characteristics, which offer protection from predators and weather, affect patch use and hence should influence their revisitation. Due to the potentially high costs of moving between patches, fragmented habitats are predicted to complicate foraging decisions of many animals. We aimed to determine how food quality, shelter availability and habitat fragmentation influence tree reuse by a specialist folivore, the koala, in a fragmented agricultural landscape. We GPS-tracked 23 koalas in northern New South Wales, Australia and collated number of revisits, average residence time, and average time-to-return to each tree. We measured tree characteristics including food quality (foliar nitrogen and toxic formylated phloroglucinol compounds, FPCs concentrations), tree size, and tree connectedness. We also modeled the costs of locomotion between trees. Koalas re-visited isolated trees with high leaf nitrogen disproportionately often. They spent longer time in trees with high leaf nitrogen, and in large trees used for shelter. They took longer to return to trees with low leaf nitrogen. Tree connectivity reduced travel costs between patches, being either individual or groups of trees. FPC levels had no detectable effect on patch revisitation. We conclude that food quality and shelter drive koala tree re-visits. Scattered, isolated trees with nutrient-rich leaves are valuable resource patches for koalas despite movement costs to reach them.
Camus, E.B., Rhodes, J.R., McAlpine, C.A., Lunney, D., Callaghan, J., Goldingay, R., Brace, A., Hall, M., Hetherington, S.B., Hopkins, M. and Druzdzel, M.J., 2022. Using expert elicitation to identify effective combinations of management actions for koala conservation in different regional landscapes. Wildlife Research.
Context: Choosing the most effective combinations of actions to manage threatened species is difficult.
Aims: This study aimed to identify the most effective combinations of six management actions for reversing population declines of koala populations in three regional landscapes (Coastal, Riverine and Hinterland) in north-east New South Wales, Australia, based on expert-elicited knowledge.
Methods: A Bayesian network was used to combine continuous probability distributions representing the impact of specific management actions and combinations of actions. Data were derived from expert elicitation. Variation within and among expert judgements was captured by incorporating submodels of individual responses. We evaluated alternative management solutions to address four mortality factors (disease and injury, vehicle strikes, domestic dogs and wild dogs/dingoes (Canis familiaris), and two habitat-related management actions (restoration and protection).
Key results: We show that there are marked differences in the expected response of the koala populations to the various management options in the three regional landscapes over a 20-year period (2019–2039), and that multiple management actions are required to arrest and reverse the decline in koala populations of north-east NSW.
Conclusions: Management actions for koala conservation should be based on regional context. Our model, in conjunction with robust expert-elicitation procedures, allows decision makers to distinguish effective from ineffective combinations of management actions for threatened species management, and has been structured so that new data can be incorporated into the model.
Implications: Model design could be easily adapted to different species or conservation contexts, and updated as new evidence becomes available, making it valuable in adaptive management for local to regional-scale conservation problems.
Pagliarani, S., Johnston, S.D., Beagley, K.W., Hulse, L. and Palmieri, C., 2022. Chlamydiosis and cystic dilatation of the ovarian bursa in the female koala (Phascolarctos cinereus): Novel insights into the pathogenesis and mechanisms of formation. Theriogenology, 189, pp.280-289.
Infection with Chlamydia pecorum is one of the main causes of progressive decline of koala (Phascolarctos cinereus) populations in Eastern Australia. Pathological changes associated with the chlamydial infection in the genital tract of female and male koalas have been widely described with reports of acute and chronic lymphoplasmacytic inflammation and the description of the cystic dilatation of the ovarian bursa. Although these disease manifestations can result in severe chronic inflammation, structural changes and even sterility, only limited data is currently available on the organism’s distribution and associated histopathological and ultrastructural changes within the upper genital tract of affected females.
This study examined the pathogenesis of the most common pathological lesion associated with chlamydiosis in female koalas, the cystic dilation of the ovarian bursa starting from the evidence that Chlamydia spp. induces disruption of the intercellular junctions in the epithelium of the reproductive organs in humans. Histology, immunohistochemistry (IHC) and transmission electron microscopy (TEM) were performed to evaluate the structural features and the expression of epithelial cell and cellular junctions’ markers in affected bursae from 39 Chlamydia-infected female koalas. Epithelial cells from the ovarian bursae of one affected animal examined by transmission electron microscopy showed severe widening of the intercellular space, as morphologic evidence of disrupted permeability of the epithelial barrier. The epithelial cell-cell junctions markers E-cadherin, β-catenin and ZO-1 expressions were significantly reduced in samples from cystic bursae when compared to normal tissue samples (P < 0.0001). On the other end, a significantly higher expression of the proliferation marker Ki67 was observed in cystic bursae compared to control samples (P < 0.0001). As these proteins are required to maintain epithelial functional integrity and cell-cell adhesive interactions, their loss may permanently impair and affect female koala fertility and suggest the molecular basis of the pathogenesis of the cystic accumulation of bursal fluid within this tissue.
Tarlinton, R.E., Legione, A.R., Sarker, N., Fabijan, J., Meers, J., McMichael, L., Simmons, G., Owen, H., Seddon, J.M., Dick, G. and Ryder, J.S., 2022. Differential and defective transcription of koala retrovirus indicates the complexity of host and virus evolution. Journal of General Virology, 103(6), p.001749.
Goldingay, R.L., Rohweder, D., Taylor, B.D. and Parkyn, J.L., 2022. Use of road underpasses by mammals and a monitor lizard in eastern Australia and consideration of the prey‐trap hypothesis. Ecology and Evolution, 12(7), p.e9075.
The federal government finally released the 2021 Australia State of the Environment report on 19 July 2022. The report mentions koalas many times, and quotes several koala scientists. Full report here: https://soe.dcceew.gov.au/
Key Findings> Environment > Natural Heritage > Recognition & protection of natural heritage >Case Study: The koala https://soe.dcceew.gov.au/heritage/environment/natural-heritage#the-koala-protecting-an-iconic-species-as-part-of-natural-heritage-management
Key Findings> Environment > Flora & Fauna > Animals > Case Study: Detecting threatened animals with drone technology. https://soe.dcceew.gov.au/biodiversity/environment/flora-and-fauna#detecting-threatened-mammals-with-drone-technology
Key Findings> Environment > People > Wellbeing and connection with kin and country: https://soe.dcceew.gov.au/indigenous/environment/people
Key Findings> Environment > Livability > The natural environment:
Key Findings > Pressures > Population > Urban development: https://soe.dcceew.gov.au/heritage/pressures/population
Key Findings > Pressures > Invasive species > https://soe.dcceew.gov.au/biodiversity/pressures/invasive-species-problematic-native-species-and-diseases