Code to analyze static occupancy of northwestern pond turtles (Actinemys marmorata) in timberland streams in the interior foothills of northern California

The purpose of this study was to evaluate the distribution of northwestern pond turtles (Actinemys marmorata) and invasive American bullfrogs (Lithobates catesbeianus) in private timberland streams of interior northern California, USA. Fieldwork for the study occurred in 2021-2022 in Lassen, Plumas, Shasta, Tehama, and Trinity counties, California, and involved visual encounter surveys and sampling for environmental DNA. We used the two detection methods as independent samples to estimate the probability of occurrence of northwestern pond turtles, and compared detection probabilities of the detection methods to one another. We used indicator variables to select variables for estimating detection and occurrence probabilities. The code presented herein reproduces the static occupancy analysis used in the study.