Translating environmental DNA for monitoring nature: species, ecosystems, policy and practice

The unprecedented biodiversity loss driven by human activity is pushing ecosystems toward collapse, threatening global economies, human health, and essential natural systems that sustain life on Earth. Restoring nature requires decisions grounded in science and evidence, gained through monitoring practices. Monitoring ecosystems is essential for guiding environmental management, but traditional biomonitoring often falls short due to time-consuming, labour-intensive methods reliant on bio-indicators and limited by an underpinning of ecosystem function and services. Environmental DNA (eDNA) is revolutionising our ability to efficiently assess biodiversity, from a single species to whole communities across the Tree-of-Life. While eDNA research is advancing rapidly, its uptake in applied sectors is lagging, where it could significantly enhance the scale, speed and sensitivity of biomonitoring. This thesis explores the gap between research and application through stakeholder engagement, develops practical guidance, and conducts primary research on policy-relevant monitoring targets, including invasive species and pathogens. Stakeholder interviews across policy, industry and academia highlight the need for improved communication tools, robust validation and standardisation of methods. These views were considered during the development of guidance for DNA monitoring with citizen science. These insights also shaped the development of a quantitative PCR (qPCR) assay for detecting the invasive Chinese mitten crab (Eriocheir sinensis), which demonstrates rigorous experimental validation using a standardised scale. Enhanced ecological assessments should integrate the suite of eDNA tools, from species to whole communities, as the efficiency of eDNA pipelines enables sampling across the continuum of eDNA to host-tissue, as explored by literature review. The molecular detection of the parasite Bonamia ostreae in native and invasive oysters will aid the Solent Oyster Restoration Project by furthering the understanding of disease spread. In summary, this thesis provides a framework for integrating enhanced eDNA-based ecological assessments into policy and practice, providing tools to inform environmental management and nature restoration.