Rietz Janine, van Beeck Calkoen Suzanne T S, Ferry Nicolas, Schlüter Jens, Wehner Helena, Schindlatz Karl-Heinz, Lackner Tomáš, von Hoermann Christian, Conraths Franz J, Müller Jörg, Heurich Marco
Department of National Park Monitoring and Animal Management, Bavarian Forest National Park, Freyunger Straβe 2, 94481 Grafenau, Germany.
Chair of Wildlife Ecology and Management, Albert Ludwigs University Freiburg, Tennenbacher Straβe 4, 79106 Freiburg, Germany.
Transbound Emerg Dis. 2023 May 15;2023:5517000. doi: 10.1155/2023/5517000. eCollection 2023.
Because animal carcasses often serve as reservoirs for pathogens, their location and removal are crucial in controlling the spread of diseases. During carcass decomposition, heat is emitted due to microbial activity and the development of maggots. Recent studies have shown that infrared sensors can be used to locate animal carcasses, but little is known about the factors influencing detection success. In this study, we investigated the potential of infrared technology to locate wild boar carcasses, as they play an important role in the spread of African swine fever. Specifically, we tested the effects of environmental and carcass conditions on the detection probability. A drone-based thermal camera was used to collect data during 379 flyovers of 42 wild boar carcasses in different stages of decomposition between September 2020 and July 2021. Generalized mixed-effect models and conditional inference trees were used to identify the environmental and carcass conditions that influenced the detection probability. Our results showed that the thermal camera accurately measured carcass temperature ( = 0.75, RMSE = 5.89°C). The probability of finding carcasses was higher in open habitats with air temperatures >3.0°C and thus conducive to maggot development (detection rate ≤80%). A forest canopy openness >29.3% and cloudy conditions or flights at dawn increased the detection rate. Moreover, carcasses infested with large amounts of maggots could be detected even in habitats with a more extensive canopy cover, whereas in dense forests, the detection probability was limited (<25%). Carcasses in an advanced stage of decomposition could still be detected as long as the difference between the carcass temperature and the air temperature was >6.4°C (≤62%). Our study demonstrates the utility of thermal imaging in searching for wild boar carcasses under specific environmental and carcass conditions and thus its use in supporting ground searches.
由于动物尸体常常是病原体的储存宿主,其位置及清除对于控制疾病传播至关重要。在尸体分解过程中,微生物活动和蛆虫的生长会产生热量。近期研究表明,红外传感器可用于定位动物尸体,但对于影响检测成功率的因素却知之甚少。在本研究中,我们调查了红外技术定位野猪尸体的潜力,因为野猪在非洲猪瘟传播中起着重要作用。具体而言,我们测试了环境和尸体状况对检测概率的影响。在2020年9月至2021年7月期间,使用基于无人机的热成像相机对42具处于不同分解阶段的野猪尸体进行了379次飞越,以收集数据。使用广义混合效应模型和条件推断树来确定影响检测概率的环境和尸体状况。我们的结果表明,热成像相机能够准确测量尸体温度(R² = 0.75,均方根误差 = 5.89°C)。在气温高于3.0°C且有利于蛆虫生长的开阔栖息地中发现尸体的概率更高(检测率≤80%)。林冠开阔度大于29.3%、阴天条件或黎明时分飞行可提高检测率。此外,即使在树冠覆盖更广泛的栖息地中,大量蛆虫寄生的尸体也能被检测到,而在茂密森林中,检测概率有限(<25%)。只要尸体温度与气温之差大于6.4°C(≤62%),处于分解后期的尸体仍可被检测到。我们的研究证明了热成像在特定环境和尸体条件下搜索野猪尸体的实用性,因此可用于辅助地面搜索。