Mr Patrick Nichols1, Dr. Kauaoa Fraiola2, Dr. Alison Sherwood1, Dr. Brian Hauk3, Mr. Keolohilani Lopes Jr.1, Mr. Colt Davis1, Mr. James Fumo1, Dr. Chelsie Counsell1, Ms. Taylor Williams4, Dr. Heather Spalding5, Dr. Peter Marko1
1University Of Hawaiʻi at Mānoa, Honolulu, United States, 2US Fish & Wildlife Service, Honolulu, United States, 3National Oceanic and Atmospheric Administration, Honolulu, United States, 4University of Alabama at Birmingham, Birmingham, United States, 5College of Charleston, Charleston, United States
Biography:
Patrick Nichols is a Ph.D. candidate in the School of Life Sciences at the University of Hawaiʻi at Mānoa. His research focuses on marine ecology, specifically the use of environmental DNA (eDNA) for tracking community composition shifts through space and time, as well as for the early detection of invasive species. Nichols has developed innovative techniques for improving the efficiency and sensitivity of eDNA methods for detecting low-abundance species in diverse marine environments. He is passionate about advancing tools for environmental conservation and management of marine ecosystems, making routine eDNA biomonitoring more accessible for managing stakeholders.
Abstract:
Early detection of nuisance species is crucial for managing threatened ecosystems and preventing their widespread establishment. Environmental DNA (eDNA) can enhance biomonitoring programs by increasing sensitivity with reduced cost and effort. However, eDNA analyses come with inherent errors that can complicate their integration into existing management frameworks. Accurate detection, especially of species in low abundance, is essential for effective containment and eradication. We developed a novel eDNA assay to detect the nuisance marine alga Chondria tumulosa in surface seawater samples from the Papahānaumokuākea Marine National Monument (PMNM), one of the largest marine reserves globally. C. tumulosa is a cryptogenic red alga that overgrows coral reefs and smothers native flora and fauna in PMNM. The eDNA assay was validated using site-occupancy detection modeling with quantitative PCR (qPCR) data, calibrated against visual estimates of benthic cover, and further confirmed with high-throughput sequencing and negative control samples. Our results showed that detection probability for C. tumulosa at occupied sites was at least 92% when multiple qPCR replicates were positive. False-positive rates were 3% or less, and false-negative errors were 11% or less. This assay is effective for routine monitoring at shallow sites (less than 10 m) even when C. tumulosa abundance is below 1%. Successful implementation of eDNA in conservation depends on balancing uncertainties from both visual and molecular methods. Our findings demonstrate the assay’s sensitivity and outline steps for inferring ecological presence-absence from molecular data, offering a reliable and cost-effective tool for detecting low-abundance nuisance species and supporting timely management interventions.