Celine Frere

and 9 more

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.

Alejandro Oliveros

and 4 more

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.

Romane Cristescu

and 5 more

Gabe O'Reilly

and 4 more