Improving Biodiversity Surveillance in Arid Systems With Environmental <scp>DNA</scp> : Detection of <scp> <i>Sceloporus</i> </scp> Lizards in Texas

ABSTRACT Arid lands account for over 40% of the terrestrial habitat on Earth yet rank among the least studied ecosystems on the planet, limiting conservation and management options. Sensitive and accurate biodiversity surveillance tools are needed to increase the efficiency of biodiversity surveys and enable effective, fit‐for‐purpose conservation measures in these habitats based on sound scientific data. Therefore, we aimed to develop species‐specific environmental DNA (eDNA) assays targeting the endangered dunes sagebrush lizard Sceloporus arenicolus and the closely related, but non‐endangered, southern prairie lizard S. consobrinus . Development began with laboratory experiments to observe eDNA shedding rates of these arid‐adapted lizards then followed with a small‐scale pilot of eDNA detection in natural habitat. In both laboratory and field trials, eDNA detection was rare, and eDNA concentrations were low. In laboratory trials, eDNA detection (i.e., presence/absence) was not statistically associated with incubation time, although detections tended to increase slightly over the first 12 h, then declined at the 24‐h timepoint. Nor did detection differ among individuals. However, detection rate did significantly relate to the DNA extraction method used, with double the number of positives occurring in CTAB‐extracted samples (54.5%; n = 24) compared to Qiagen PowerMax Soil (27.3%; n = 12) or Machery Nagel NucleoSpin Soil (27.3%; n = 12) kits. Considering a continuous response variable (i.e., eDNA concentration), model selection provided limited evidence that time and extraction method may influence eDNA concentration, though neither of these factors were statistically significant on its own. In field applications, while we did not visually confirm any lizards utilizing coverboards (although we did observe tail‐dragging tracks) we were able to detect S. consobrinus eDNA. Overall, our results inspire cautious optimism about the potential benefit of eDNA analysis for biodiversity study and management in arid lands and lay the foundation for continued work in this space.