Determining the efficacy of camera traps, live capture traps, and detection dogs for locating cryptic small mammal species

Metal box (e.g., Elliott, Sherman) traps and remote cameras are two of the most commonly employed methods presently used to survey terrestrial mammals. However, their relative efficacy at accurately detecting cryptic small mammals has not been adequately assessed. The present study therefore compared the effectiveness of metal box (Elliott) traps and vertically oriented, close range, white flash camera traps in detecting small mammals occurring in the Scenic Rim of eastern Australia. We also conducted a preliminary survey to determine effectiveness of a conservation detection dog (CDD) for identifying presence of a threatened carnivorous marsupial, Antechinus arktos, in present-day and historical locations, using camera traps to corroborate detections. 200 Elliott traps and 20 white flash camera traps were set for four deployments per method, across a site where the target small mammals, including A. arktos, are known to occur. Camera traps produced higher detection probabilities than Elliott traps for all four species. Thus, vertically mounted white flash cameras were preferable for detecting the presence of cryptic small mammals in our survey. The CDD, which had been trained to detect A. arktos scat, indicated in total 31 times when deployed in the field survey area, with subsequent camera trap deployments specifically corroborating A. arktos presence at 100% (3) indication locations. Importantly, the dog indicated twice within Border Ranges National Park, where historical (1980s-1990s) specimen-based records indicate the species was present, but extensive Elliott and camera trapping over the last 5-10 years have resulted in zero A. arktos captures. Camera traps subsequently corroborated A. arktos presence at these sites. This demonstrates that detection dogs can be a highly effective means of locating threatened, cryptic species, especially when traditional methods are unable to detect low-density mammal populations.

金属箱式诱捕器（如埃利奥特（Elliott）诱捕器、谢尔曼（Sherman）诱捕器）与远程相机，是当前陆生哺乳动物调查中最为常用的两类方法。然而，二者在精准侦测隐秘小型哺乳动物方面的相对效能尚未得到充分评估。为此，本研究对比了金属箱式（埃利奥特）诱捕器与垂直布设、近距离、白光触发的相机诱捕器，在澳大利亚东部风景山脊（Scenic Rim）区域内侦测小型哺乳动物的效能。本研究同时开展了一项初步调查，旨在评估保护探测犬（conservation detection dog, CDD）在现代与历史分布点位识别受威胁食肉有袋类物种Antechinus arktos的效能，并借助相机诱捕器对探测结果予以佐证。研究团队在已知包含目标小型哺乳动物（含A. arktos）的分布区域内，针对每种方法开展4次布设，共部署200台埃利奥特诱捕器与20台白光触发相机诱捕器。相较于埃利奥特诱捕器，相机诱捕器对全部4个物种的侦测概率均更高。因此，在本研究的调查场景中，垂直布设的白光触发相机更适于侦测隐秘小型哺乳动物的存在。本次研究中经过训练以侦测Antechinus arktos粪便的保护探测犬，在野外调查区域内共发出31次探测提示；后续部署的相机诱捕器证实，3处提示点位均100%存在该物种。值得注意的是，该探测犬在边界山脉国家公园（Border Ranges National Park）内两次发出探测提示；该区域的历史（1980-1990年代）标本记录显示曾有该物种分布，但过去5-10年间开展的大规模埃利奥特诱捕与相机诱捕均未捕获到A. arktos个体。后续相机诱捕器证实了该区域存在Antechinus arktos。该结果表明，探测犬可成为定位受威胁隐秘物种的高效手段，尤其在传统方法无法侦测低密度哺乳动物种群的场景下，其优势尤为显著。