Abstract
Illegal hunting (poaching) is a global threat to wildlife. Anti-poaching initiatives are making increasing use of technology, such as infrared thermography (IRT), to support traditional foot and vehicle patrols. To date, the effectiveness of IRT for poacher location has not been tested under field conditions, where thermal signatures are often complex. Here, we test the hypothesis that IRT will increase the distance over which a poacher hiding in African scrub bushveldt can be detected relative to a conventional flashlight. We also test whether any increase in effectiveness is related to the cost and complexity of the equipment by comparing comparatively expensive (22000 USD) and relatively inexpensive (2000 USD) IRT devices. To test these hypotheses we employ a controlled, fully randomised, double-blind procedure to find a poacher in nocturnal field conditions in African bushveldt. Each of our 27 volunteer observers walked three times along a pathway using one detection technology on each pass in randomised order. They searched a prescribed search area of bushveldt within which the target was hiding. Hiding locations were pre-determined, randomised, and changed with each pass. Distances of first detection and positive detection were noted. All technologies could be used to detect the target. Average first detection distance for flashlight was 37.3m, improving by 19.8m to 57.1m using LIRT and by a further 11.2m to 68.3m using HIRT. Although detection distances were significantly greater for both IRTs compared to flashlight, there was no significant difference between LIRT and HIRT. False detection rates were low and there was no significant association between technology and accuracy of detection. Although IRT technology should ideally be tested in the specific environment intended before significant investment is made, we conclude that IRT technology is promising for anti-poaching patrols and that for this purpose low cost IRT units are as effective as units ten times more expensive.
Highlights
Illegal hunting is a major wildlife problem in many regions of the world
HIRT added 11.2m to mean first detection distance of LIRT, which gave a 19.8m advantage over a flashlight. This meant that detection distances almost doubled using HIRT relative to traditional flashlight technology
Though both infrared thermography (IRT) devices were capable of detecting the poacher at significantly greater distances than a flashlight, we found no evidence to support the hypothesis that more expensive equipment would provide a greater detection distance
Summary
Illegal hunting is a major wildlife problem in many regions of the world. A key driver of illegal hunting (hereafter referred to as poaching) is increasing urban expansion, which causes human encroachment of wildlife areas, elevated pressure on natural resources, and an increasing demand for bushmeat [1,2]. Subsistence hunting, where animals are taken to satisfy immediate local demand for food, still exists, but poaching is increasingly undertaken to supply more commercially-organised demand for bushmeat [3]. This demand is both within the country of origin and, increasingly, internationally (e.g., an estimated five tonnes per week is imported into Paris, from where it is distributed to other sites across Europe [4]). African elephants are still killed for the illegal ivory trade [10,11,12], while endangered pangolins are subject to extreme poaching pressure for their scales [13,14]. Poaching is a significant problem both for long-term sustainability of animal populations and for those trying to control it
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