Fig 1.
Layout of camera trap and labour-intensive survey devices on transects.
Image a) is the spatial configuration of devices along the transect, and b) the configuration of artificial refuge arrays over ~3 m of transect. Artificial refuge arrays consisted of: A, concrete roof tiles; B, railway sleepers; and C, a pair of corrugated steel sheets stacked one on top of the other.
Fig 2.
The a) plan view and b) profile view of the camera trap station setup. Components are: A, drift fence (~30 x ~300 cm); B, cork floor tile (30 x 30 x 0.6 cm); C, passive infrared (PIR) detection bands to demonstrate orientation; D, Reconyx HC600 camera trap; E, PVC bait-holder; and F, camera mounting pole. The camera trap is mounted ~70 cm above the tile with the PIR sensor oriented furthest from the mounting pole.
Table 1.
Survey protocol combinations.
Table 2.
Equipment and implementation expenses to conduct a survey.
Table 3.
Number of transects at which squamate species were detected.
Fig 3.
Comparison of survey protocols.
Probability that the number of species detected by the Xi survey protocol was greater than or equal to the number of species detected by the Yj survey protocol. Probabilities were calculated from 10000 draws from the survey protocol’s posterior distribution. Survey protocols are: All-74, detections from all protocols during the 74 days; CT-74, detections from camera traps during the 74 days; All-16, detections from all using all protocols during the 16 days of the labour-intensive methods survey; CT-16, detections from camera traps during the 16 days of the labour-intensive methods survey; and LI, combined detections of artificial refuges (AR) and pitfall traps (PF).
Table 4.
Equipment and implementation expenses.
Fig 4.
Total cost and marginal cost for terrestrial squamate surveys with various survey protocols.
Plot a) depicts the total cost for the 74-day camera trapping protocol (CT-74; solid line) and artificial refuges alone (AR; dashed line) at two rate-of-replacement (RoR; 0 and 30%) and hourly rate of labour (h; $0 and $55) values. Plot b) depicts the average marginal cost over all values of RoR and hourly labour (black dots) and average marginal cost for a realistic scenario whereby RoR is < 10% and hourly wage > $10 (white dots). Survey protocols are: All-74, detections from all protocols during the 74 days; CT-74, detections from camera traps during the 74 days; All-16, detections from all using all protocols during the 16 days of the labour-intensive methods survey; CT-16, detections from camera traps during the 16 days of the labour-intensive methods survey; and LI, combined detections of artificial refuges (AR) and pitfall traps (PF). Dots in plot b) represent means and bars 95% confidence interval.
Fig 5.
Cost ($’000) per squamate species detected as a function of survey protocol.
Black dot estimates are calculated from the average marginal cost over all values of RoR and hourly labour, and white dots are calculated from the average marginal cost for a realistic scenario whereby RoR is < 10% and hourly wage > $10. Survey protocols are: All-74, detections from all protocols during the 74 days; CT-74, detections from camera traps during the 74 days; All-16, detections from all using all protocols during the 16 days of the labour-intensive methods survey; CT-16, detections from camera traps during the 16 days of the labour-intensive methods survey; and LI, combined detections of artificial refuges (AR) and pitfall traps (PF). Central dots represent the mean of the posterior distribution and bars represent 95% credible intervals.