The use of scats is a widespread non-invasive method in ecological studies of mammalian carnivores. However, their low detectability and the incorrect species assignment may be important sources of bias. We aimed to optimize the detection and identification of scats of Egyptian mongoose (Herpestes ichneumon), using the red fox (Vulpes vulpes) as a comparative model. Based on molecular identification of scats we assessed: (1) the accuracy of species morphological identification (Field-ID); (2) whether post-field laboratory analyses (FL-ID) improve Field-ID; (3) species-specific morphological differences of scats, and (4) whether specific field surveys increase the detectability of mongoose scats. Out of 175 collected scats, 81 were genetically identified. Field-ID accuracy was over 75.6% for the mongoose and over 45.0% for the red fox. Misidentified mongoose scats mainly belonged to stone marten (50.0%) while misidentified red fox scats mainly belonged to mongoose (63.6%). After applying FL-ID, accuracy increased to 93.1% for the Egyptian mongoose and 76.2% for the red fox. Morphological scat differences were only significant for the scat diameter, with red fox scats being significantly thicker than those of mongoose. More mongoose scats were found along ecotones (mean ± SE: 4.05 ± 1.45 scats/transect) than along trails and roads (0.05 ± 0.05 scats/transect), while red fox scats were found similarly in both transect types. The application of post-field analysis to scats and focusing the search along ecotones optimized both the identification accuracy and the detection probability of Egyptian mongoose scats, although searching for scats in other structures should not be discarded if the aim is the study of habitat use or selection by the species. Our results can be useful for scat identification in studies on this and other carnivore species.

中文翻译：

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检测和识别欧洲西南部不断扩大的中食肉动物粪便的方法学改进

在哺乳动物食肉动物的生态研究中，粪便的使用是一种广泛的非侵入性方法。然而，它们的低可检测性和不正确的物种分配可能是偏差的重要来源。我们旨在优化埃及猫鼬 (Herpestes ichneumon) 粪便的检测和识别，使用红狐 (Vulpes vulpes) 作为比较模型。基于粪便的分子鉴定，我们评估了：（1）物种形态鉴定（Field-ID）的准确性；(2) 后场实验室分析（FL-ID）是否改进了Field-ID；(3) 特定物种的粪便形态差异，以及 (4) 特定的实地调查是否增加了猫鼬粪便的可检测性。在收集的 175 份粪便中，有 81 份经过基因鉴定。猫鼬的 Field-ID 准确度超过 75.6%，红狐超过 45.0%。误判的猫鼬猫鼬主要为石貂（50.0%），误判的红狐猫猫主要为猫鼬（63.6%）。应用 FL-ID 后，埃及猫鼬的准确率提高到 93.1%，红狐的准确率提高到 76.2%。形态学粪便差异仅在粪便直径方面显着，红狐粪便明显比猫鼬更厚。沿交错带发现的猫鼬粪便（平均值±SE：4.05±1.45 scats/横断面）比沿小径和道路（0.05±0.05 scats/横断面）发现的猫鼬粪便更多，而在两种横断面类型中都发现了类似的红狐粪便。将后场分析应用于猫鼬并沿着交错带集中搜索，优化了埃及猫鼬猫的识别准确度和检测概率，尽管如果目的是研究栖息地使用或物种选择，则不应放弃在其他结构中寻找粪便。我们的结果可用于对这种和其他食肉动物物种的研究中的粪便识别。