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Real-time drone derived thermal imagery outperforms traditional survey methods for an arboreal forest mammal.

Authors :
Witt RR
Beranek CT
Howell LG
Ryan SA
Clulow J
Jordan NR
Denholm B
Roff A
Source :
PloS one [PLoS One] 2020 Nov 16; Vol. 15 (11), pp. e0242204. Date of Electronic Publication: 2020 Nov 16 (Print Publication: 2020).
Publication Year :
2020

Abstract

Koalas (Phascolarctos cinereus) are cryptic and currently face regional extinction. The direct detection (physical sighting) of individuals is required to improve conservation management strategies. We provide a comparative assessment of three survey methods for the direct detection of koalas: systematic spotlighting (Spotlight), remotely piloted aircraft system thermal imaging (RPAS), and the refined diurnal radial search component of the spot assessment technique (SAT). Each survey method was repeated on the same morning with independent observers (03:00-12:00 hrs) for a total of 10 survey occasions at sites with fixed boundaries (28-76 ha) in Port Stephens (n = 6) and Gilead (n = 1) in New South Wales between May and July 2019. Koalas were directly detected on 22 occasions during 7 of 10 comparative surveys (Spotlight: n = 7; RPAS: n = 14; and SAT: n = 1), for a total of 12 unique individuals (Spotlight: n = 4; RPAS: n = 11; SAT: n = 1). In 3 of 10 comparative surveys no koalas were detected. Detection probability was 38.9 ± 20.03% for Spotlight, 83.3 ± 11.39% for RPAS and 4.2 ± 4.17% for SAT. Effective detectability per site was 1 ± 0.44 koalas per 6.75 ± 1.03 hrs for Spotlight (1 koala per 6.75 hrs), 2 ± 0.38 koalas per 4.35 ± 0.28 hrs for RPAS (1 koala per 2.18 hrs) and 0.14 ± 0.14 per 6.20 ± 0.93 hrs for SAT (1 koala per 43.39 hrs). RPAS thermal imaging technology appears to offer an efficient method to directly survey koalas comparative to Spotlight and SAT and has potential as a valuable conservation tool to inform on-ground management of declining koala populations.<br />Competing Interests: The authors have declared that no competing interests exist.

Details

Language :
English
ISSN :
1932-6203
Volume :
15
Issue :
11
Database :
MEDLINE
Journal :
PloS one
Publication Type :
Academic Journal
Accession number :
33196649
Full Text :
https://doi.org/10.1371/journal.pone.0242204