Conceptual illustration of 3-level occupancy model.

Conceptual illustration of 3 levels including variable names, but not subscripts (variables are formally defined in text and Table 1). The river illustration shows sampling the same site multiple times. Each visit either had eDNA detected (Z = 1) or not detected (Z = 0) with probability ψ. The individual samples taken from the river (lower left) illustrate multiple samples being taken at a site during a visit. Samples either had eDNA detected within them (A = 1) or not (A = 0) with probability θ. Samples processed in the lab (lower right) either had eDNA detections (Y = 1) or no detections (Y = 0) with probability p.