Detection of Procambarus clarkii by funnel traps and environmental DNA depends on pond characteristics and crayfish abundances

The presence of Procambarus clarkii was surveyed in a network of 158 ponds in France by using funnel traps and eDNA analyses concomitantly. Ponds were described using 6 habitat variables: perimeter, surface, maximum depth (sometimes estimated), estimated volume, mean shoreline slope and occurrence of litter. Additionally, 5 water quality variables (temperature, turbidity, conductivity, pH and dissolved oxygen) were measured on a subsample of 82 ponds. For the 51 ponds where crayfish were trapped, CPUE (catch per unit effort - number of crayfish per trap per 24h) and the proportion of juveniles were calculated.