COS 274-4 - Biodiversity monitoring with eDNA in the Sierra de Manantlán, México

Abstract: Mesoamerica is the planet’s third largest biodiversity hotspot and a critical landscape for conservation amid the global biodiversity decline crisis. Historical methods for monitoring biodiversity have relied on expensive equipment and intensive field operations that only detect a limited sample of species. Other conservation challenges, like illicit poaching and other activities, present a safety risk for those conducting research in Mesoamerica that may be reduced with novel, non-invasive biodiversity monitoring techniques like environmental DNA (eDNA). Advancements in next-generation sequencing and metabarcoding technologies provides the opportunity to identify organisms from environmental DNA in soil and water. The Sierra de Manantlán is a mountainous UNESCO Biosphere Reserve located at the transition between the Nearctic and Neotropical realms in the Mexican states of Jalisco and Colima. It is one of the most important protected areas in Western Mexico due to its diverse forest ecosystems, habitat for threatened species like the jaguar (Panthera onca) and margay (Leopardus wiedii), and ecosystem services including freshwater used by more than 600,000 people. The goals of this novel eDNA biodiversity survey are to monitor organisms detected in eDNA samples from around the University of Guadalajara’s Las Joyas Research Station located in the core habitat of the reserve. Water-derived eDNA samples were collected from three streams in the reserve and DNA extractions were done at the University of Guadalajara’s local CUCSUR campus before sequencing and downstream analysis at UC Santa Cruz. Additionally, soil-derived eDNA samples were collected at camera trap sites to compare species detection probability of terrestrial vertebrates. Preliminary results from water-derived eDNA samples recorded all fish families known to inhabit the reserve, including commercially introduced and invasive species like the European carp (Cyprinus carpio). Here we show a promising tool for monitoring native biodiversity and community composition, as well as detecting biological invasions with eDNA in the Sierra de Manantlán. In conclusion, this study suggests eDNA as a promising tool to complement camera trap networks and other biodiversity monitoring techniques.