Perched high up in a Eucalyptus tree, swaying from side to side, lies a sleepy koala unaware of the means spent each year trying to obtain accurate baseline information about its presence. We have thrown all we could at it, from wildlife surveys to night spotting, bioacoustics, detection dogs, and drones equipped with thermal cameras. Yet, whilst critical to its conservation and management efforts, finding a koala remains an ambitious, time-consuming, and costly endeavour often producing insufficient results. However, little did we know that traces of koalas’ presence and that of its predators along with other native, domesticated, and invasive species, float in the air and can be detected using metagenomics. This study and despite high levels of co-sampled non-target DNA (e.g. humans and domesticated animals) confirms that koalas, species belonging to the wallaby and possum family and threats such as domestic dogs (a major predator contributing to koala population declines) can successfully be detected by sampling airborne particles. Together, it demonstrates the potential of airborne eDNA for the detection of terrestrial wildlife under natural conditions and presents achievable optimisation steps to increase its field applicability and validity.

Linear infrastructure stands as one of the main culprits of anthropogenically caused biodiversity decline. As it fragments landscapes, it ultimately results in a myriad of direct and indirect ecological consequences for wildlife. As transportation networks will continue to grow under increasing human population growth, biodiversity will continue to decline making the need to understand and mitigate their impact on species an urgent need for conservation worldwide. The implementation of mitigation measures to alleviate the barrier effect produced by linear transport infrastructure on local fauna is not new, and research has shown that their effectiveness has been shown to be influenced by their design, their placement and the biology of the impacted species. Our understanding of their effectiveness in preventing the longer-term impacts of linear transport infrastructure on habitat connectivity via gene flow, however, remains poorly understood. Here, we used a pre- and post-habitat fragmentation genetic dataset collected as part of an extensive Koala Management Program to ask questions about the immediate and predicted longer-term genetic consequences of linear transport infrastructure on the impacted species. Importantly, using forward migration simulations, we show that to preserve connectivity would need to result in around 20% of the population mixing to avoid long-term genetic drift. These results have important consequences for the management of species at the forefront of linear infrastructure. In particular, the study shows the importance of considering gene flow in our assessment of the effectiveness of fauna crossings.

The study of the host-microbiome by the collection of non-invasive samples has the potential to become a powerful tool for conservation monitoring and surveillance of wildlife. However, multiple factors can bias the quality of data recovered from scats, particularly when field-collected samples are used given that the time of defecation is generally unknown and could have been as recent as hours, days, or weeks. Previous studies using scats have shown that exposure to aerobic conditions can compromise the microbial composition and that this rate of exposure differs between species. However, the impact that this aging process has on the relationship between the bacterial and fungal composition has yet to be explored. In this study, we measured the effects of time post-defecation on bacterial and fungal compositions and structures in a controlled experiment using scat sample from the endangered koala (Phascolarctos cinereus). We found that targeting the core of the scat for DNA extraction reduced the impact of oxygen exposure as we did not observe the previously reported reduction in obligate anaerobic bacteria nor an increase in facultative anaerobes even after aging for 10 days. We found that even though bacteria remain stable through the scat aging process, the fungal composition did not. We report a cluster of fungal taxa that colonises scats after defecation which can dilute the genetic material from the autochthonous mycoflora and inhibit recovery. Finally, we propose strategies to combat the effects of time and preserve the integrity of a scat sample collected in the wild.

Infectious fungal diseases can have devastating effects on wildlife health and our ability to detect emerging fungal pathogens in the wild is considered indispensable for effective management strategies. Several fungi from the genus Nannizziopsis and Paranannizziopsis are emerging pathogens of reptiles and have been observed to cause disease in a wide range of taxa. Nannizziopsis barbatae has become a particularly important pathogen of Australian reptiles with an increasing number of herpetofauna being reported with cases of infection from across the country. Here, we report a species-specific qPCR assay for the rapid detection of N. barbatae and demonstrate its application in a wild urban population of a dragon lizard. In addition, we present the mitochondrial genome sequences and phylogenetic analysis for seven species in this group of fungi to support further research into the evolutionary ecology of these emerging pathogens.