Fig 1.
Study site map and survey locations in Port Stephens on the east coast of New South Wales (NSW), Australia.
Fig 2.
Conceptual diagram of the three survey methodologies (Spotlight, RPAS, SAT) conducted within a fixed site quadrat (28–76 ha in size) at each survey location on the same morning in Port Stephens and Gilead, NSW, Australia.
(a) Systematic spotlighting nocturnal line-transect (Spotlight) spaced ~100 m apart with an observation distance of 50 m perpendicular to the left and right of the transect line, 03:00–06:00 hrs; (b) remotely piloted aircraft system thermal imaging (RPAS) flown in a lawn mower pattern as per Beranek et al. 2020 [29], 04:00–07:30 hrs; (c) the refined spot assessment technique (SAT) a grid-based arrangement at a frequency of one SAT survey per 8.6 ± 1.21 ha, 08:00–12:00 hrs.
Fig 3.
Mean koala (Phascolarctos cinereus) detections per survey by method (Spotlight, RPAS, SAT) across low density peri-urban sites in Port Stephens (n = 6 per method) and Gilead (n = 1 per method) on the east coast of NSW, Australia.
Table 1.
Koala (Phascolarctos cinereus) density estimates by survey method: Spotlight, RPAS, SAT per site.
Table 2.
The detectability success of the koala (Phascolarctos cinereus) based on effort requirements (person hours) of the three survey methods: Spotlight, RPAS, and SAT.
Table 3.
Koala (Phascolarctos cinereus) site and tree activity informed by the spot assessment technique (SAT) for each survey site in Port Stephens and Gilead, NSW, Australia.
Table 4.
Comparison of tree species used by koalas (Phascolarctos cinereus) identified by direct observation (Spotlight, RPAS) or by indirect observation (SAT) within Port Stephens on the east coast of NSW, Australia (Site: PS-1 to PS-6).