Noninvasive identification of cryptic herpetofauna from fecal samples: A novel approach pairing conservation dog surveys and genetic analysis

Noninvasive fecal sampling combined with genetic analysis is a powerful technique allowing the study of elusive or otherwise difficult to monitor species without the need for direct contact. While this method is widely used in birds and mammals, it has never been successfully applied on a large scale in reptiles. The blunt-nosed leopard lizard (Gambelia sila) is an endangered species endemic to the San Joaquin Desert of California. Presently, acquiring data on G. sila for research and management involves more traditional methods such as live capture to obtain tissue samples for DNA analysis, or observation via visual surveys, which are also used for regulatory monitoring in accordance with wildlife agency protocols. Here we describe an innovative approach for gathering additional information, that combines use of conservation detection dogs trained to locate G. sila scat samples with genetic analysis for identifying and distinguishing among sympatric lizard species. We developed two PCR assays that produce fluorescently labelled amplicons of species-specific fragment length for six lizard species in the study area. Using these assays we genetically identifed to species 78% (255 of 327) of samples collected by dog-handler teams across four years. The majority of the genetically identifed samples (82.4%; 210 of 255) were confirmed as originating from G. sila. Beyond the immediate application of these techniques for the study and monitoring of G. sila, our ability to recover usable DNA and to differentiate among a diverse group of lizards highlights the broad potential of our methodology for noninvasive sampling in reptiles.