Effectiveness of thermal cameras compared to spotlights for counts of arid zone mammals across a range of ambient temperatures
Hugh McGregor
A B C F , Katherine Moseby C D , Christopher N. Johnson A B and Sarah Legge A E
A National Environmental Science Program Threatened Species Recovery Hub, Centre for Biodiversity and Conservation Science, University of Queensland, St Lucia, Qld 4075, Australia.
B School of Natural Sciences, Private Bag 55, University of Tasmania, Hobart, Tas. 7001, Australia.
C Arid Recovery, PO Box 147, Roxby Downs, SA 5725, Australia.
D University of New South Wales, Sydney, NSW 2052, Australia.
E Fenner School of Environment and Society, The Australian National University, Canberra, ACT 2601, Australia.
F Corresponding author. Email: hugh.mcgregor@utas.edu.au
Australian Mammalogy 44(1) 59-66 https://doi.org/10.1071/AM20040
Submitted: 4 June 2020 Accepted: 6 February 2021 Published: 12 March 2021
Abstract
Effective monitoring of mammal species is critical to their management. Thermal cameras may enable more accurate detection of nocturnal mammals than visual observation with the aid of spotlights. We aimed to measure improvements in detection provided by thermal cameras, and to determine how these improvements depended on ambient temperatures and mammal species. We monitored small to medium sized mammals in central Australia, including small rodents, bettongs, bilbies, European rabbits, and feral cats. We conducted 20 vehicle-based camera transects using both a spotlight and thermal camera under ambient temperatures ranging from 10°C to 35°C. Thermal cameras resulted in more detections of small rodents and medium sized mammals. There was no increased benefit for feral cats, likely due to their prominent eyeshine. We found a strong relationship between increased detections using thermal cameras and environmental temperature: thermal cameras detected 30% more animals than conventional spotlighting at approximately 15°C, but produced few additional detections above 30°C. Spotlighting may be more versatile as it can be used in a greater range of ambient temperatures, but thermal cameras are more accurate than visual surveys at low temperatures, and can be used to benchmark spotlight surveys.
Keywords: arid zone mammals, conservation, detectability, distance sampling, monitoring, spotlighting, thermal imagery.
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