K’gari (Fraser Island), a UNESCO World Heritage-listed site, is home to unique ecosystems vulnerable to invasive pests, pathogens, and weeds. Vehicles arriving on the island may inadvertently transport biosecurity threats via mud, plant debris, and soil attached to tyres and undercarriages. To address this risk, we conducted a metabarcoding-based survey to characterise the biodiversity of potential hitchhikers and identify taxa of high-risk to K’gari’s forest ecosystems.
K’gari falls under the traditional custodianship of the Butchulla Aboriginal Corporation (BAC) and Butchulla Land and Sea Rangers (BLRS). In collaboration with the Butchulla Rangers, the Queensland Department of Primary Industries (QDPI), Queensland Parks and Wildlife Service (QPWS), and CSIRO, we co-designed an experiment to collect soil and debris samples from vehicles arriving on K’gari via ferry. Environmental DNA (eDNA) was extracted from these samples and subjected to high-throughput sequencing of the full ITS region, the trnL gene, and the COI gene, targeting key taxonomic groups including fungi, plants (weeds), and insects. Soil baiting was also conducted at GrowHelp to find Oomycetes, with a focus on Phytophthora cinnamomi, a local threat to native and cultivated ecosystems.
Bioinformatics pipelines were used to process sequence data, filter contaminants, and assign taxonomy, providing insights into species diversity and the presence of known or emerging biosecurity threats.
The study aimed to:
Preliminary results highlight the range of organisms present and their relative abundance, offering critical data to refine biosecurity strategies. The findings support evidence-based management interventions to prevent the establishment of invasive species on K’gari, safeguarding its fragile ecosystems.
We also present some learnings from a co-designed ‘biosecurity bioblitz’ conducted on K’gari with the same team and the support of the World Heritage Trust and the Australian Chief Biosecurity Officer. This field survey focused on weeds, pests and diseases of native plants in forest ecosystems. Locations chosen were based on the priorities of the Butchulla Rangers, and on previous observations of biosecurity concern on the island. The authors provided training material and hands-on fieldwork to support rangers to develop skills in symptom observations, pathogen and insect identification, preferred host species, and weeds of concern. This was followed by a week of lab-based training for a smaller group of Butchulla rangers to learn about downstream sample analysis, fungal isolation and microscopy, DNA extraction, and insect identification.
Working alongside the Traditional Custodians has enabled knowledge sharing and learning opportunities for all involved, supporting Ranger efforts to care for Country. By leveraging metabarcoding, bioinformatics, and morphological identification, this research provided a scalable approach to monitoring biosecurity risks at other environmentally sensitive locations. The study underscored the importance of collaborative research efforts and proactive surveillance in preventing the introduction and spread of invasive species via human-mediated pathways.