Microbiome Research Applications for the Management and Conservation of the Tasmanian Devil

Abstract

The Tasmanian devil (Sarcophilus harrisii) is a carnivorous marsupial endemic to the island state of Tasmania, Australia. Devil Facial Tumor Disease (DFTD) is a rare type of clonally transmissible cancer that has caused widespread declines in Tasmanian devil populations. Tasmanian devils are managed in a metapopulation framework consisting of translocations between captive-breeding facilities and wild sites. Effective management of threatened species such as the Tasmanian devil requires carefully planned conservation strategies from multiple disciplines, including microbiome research. The gut microbiome exists in a dynamic state of different microbes that are linked to host metabolic and immune function. Similar to how a decrease in biodiversity can lead to a decrease in ecosystem health, a change in microbial species can lead to dysbiosis and negatively influence host health. Dysbiosis occurs from environmental changes (including captivity and disease) and may undermine conservation efforts, including translocations. Studying microbiomes can provide valuable information on how species adapt to novel environments, respond to diseases, and may even be harnessed to increase the health and fitness of organisms. It is therefore essential to utilize microbiome research in threatened species management. In this dissertation, I first explored the use of microbiome analyses in translocations by systematically reviewing published research to identify main objectives and findings. I then conducted the first range-wide assessment of Tasmanian devil gut microbiomes and found that location and age group had significant effects on the bacterial communities, but diet only explained a small amount of the variation. Lastly, I investigated the impact of DFTD on the Tasmanian devil gut microbiome and found no evidence of dysbiosis but did identify differentially abundant microbes and more variability in neutrophil:lymphocyte ratios (NLR) in devils with DFTD. This dissertation advances conservation strategies by providing insight into how microbiome analyses can be directly integrated into threatened species management.