Fig. 2

Observed detection probability (proportion) for 152 and 158 dB acoustic transmitters as a function of distance between transmitter and active tracking receiver (VR100). Proportion of detections was based on total detections (coding of transmitter signal) during 20 min of sampling. For each transmitter type (power), detections were made at six transmitter locations associated with stands of senescent emergent Phragmites spp. (three inside (0.5 m) and three outside (0.5 m)) in April 2019. At each location, detections were made at four distances from the transmitter and for four gain settings of the receiver