Terrestrial mammal register camera trapping in Galicia

Although most mammals live in terrestrial environments, it is difficult to see them in the wild. However, there is a wide variety of techniques for their detection. Currently, camera trapping is the most widely used non-invasive detection technique. Thus, we used this methodology to determine the optimal variables to carry out mammals’ camera trapping assessments in the wild. From 2016 to 2020, we placed 20 camera traps in Os Montes do Invernadeiro Natural Park (Ourense, Galicia), from which we obtained 8,044 records (photographs and videos). We obtained significant differences between records frequencies in each category of climatic environmental and seasonal variables according to the mammal species. As well, the atmospheric mean temperature, location and period were the most determinant variables to correlate detection events of different mammal species. On the basis of a generalized lineal model (GLM) we obtained a great number of events in deciduous and pine forests, during summer and autumn, and on nights of waxing and waning quarters; of both predators, which appear in locations with crossroads, and prey, which avoid these crossroads. Therefore, it can be stated that there are optimal climatic, environmental and seasonal conditions to carry out camera trapping studies on mammal species.

尽管多数哺乳动物栖息于陆地生境，但野外实地目击其踪迹的难度较高。不过，针对这类动物的野外探测技术手段多样。目前，红外相机陷阱法（camera trapping）是应用最为广泛的非侵入式探测技术。因此，本研究采用该方法，旨在确定开展野外哺乳动物红外相机陷阱调查的最优影响变量。2016年至2020年间，研究团队在西班牙加利西亚自治区奥伦塞省的因弗纳德罗山自然公园内布设了20台红外相机，最终获取8044条有效记录（含照片与视频素材）。分析结果显示，不同哺乳动物类群的记录频次在气候环境、季节变量的各分类维度下均存在显著差异；大气平均温度、布设点位与调查时段，是影响不同哺乳动物物种探测事件的最关键变量。基于广义线性模型（Generalized Linear Model, GLM）的分析结果表明：在落叶林与松林生境、夏秋两季以及上下弦月的夜间，探测事件发生频次较高；捕食者多分布于交叉路口附近区域，而猎物则会主动规避此类点位。综上，针对哺乳动物开展红外相机陷阱调查研究，存在适配的最优气候、环境与季节条件。