DEVELOPMENT OF A QUANTITATIVE POLYMERASE CHAIN REACTION ASSAY AND ENVIRONMENTAL DNA SAMPLING METHODS FOR GIANT GARTERSNAKES (THAMNOPHIS GIGAS).
Gregory Schumer; Genidaqs; 3300 Indutrial Blvd suite 100, West Sacramento, CA, 95691; (916) 231-1687; greggs@fishsciences.net; Scott Blankenship, Eric Hansen
Giant gartersnakes (Thamnophis gigas) are a visually evasive species living at low density, which results in low detection probability using standard field survey methods (e.g., traps, video). Enhancing survey method sensitivity through use of eDNA survey techniques would improve compliance monitoring under the Endanger Species Act, recovery planning for T. gigas, and evaluation of California's Central Valley tule marsh habitat on which this species depends. We designed and validated diagnostic qPCR assays for identifying fragments of the Cytochrome B (CytB) and the NADH dehydrogenase 4 (ND4) genes of the T. gigas mitochondrial genome. The ND4 qPCR assay was shown to be not specific to T. gigas DNA and amplified DNA from closely related and co existing Thamnohpis. The CytB T. gigas qPCR assay proved specific to a species and reliably detected T. gigas DNA. Coordinated field sampling was conducted at aquatic sites with an observed and documented population of T. gigas with the intent of refining eDNA sample collection and survey protocol. This presentation will provide an overview of qPCR assay development, refinement of eDNA field survey protocol, and the application of an eDNA survey to establish a contemporary occupancy model for T. gigas.
Ecology and Conservation of Amphibians and Reptiles III