Counts of independent photo events from camera traps are commonly used to make inference about species occupancy, the density of unmarked populations, and the relative abundance of species across time and space. These applications rest on the untested assumption that data collected from individual cameras are representative of the landscape location in which they are placed, and that nearby cameras would record similar data when any additional micro‐site differences are accounted for. We established a high‐density camera trapping grid (100 × 100 m; 27 cameras) in Virginia, USA, to explicitly test these assumptions, investigating variation in capture rates and detection probabilities for a range of terrestrial mammals during four 2‐month seasonal surveys. Despite controlling for numerous habitat and placement factors, we documented, across all 5 focal species, large ranges and coefficients of variation in both capture rate and detection probabilities, which were similar to those seen across 2 sets of independent forest sampling sites from a larger, more typical camera trap sampling design. We also documented a lack of spatial autocorrelation in capture rate at any distance. Measured local covariates relevant to the camera viewshed (stem density, camera height, log presence, effective detection distance [EDD], total dbh of oak trees) rarely explained any significant portion of observed variation in capture rates or detection probabilities across the grid. The influence of EDD, measured here for the first time for individual camera stations, was inconsistently important and varied in direction of effect depending on species and season. Our study indicates single‐camera stations may fail to sample animal presence and frequency of use in a robust and repeatable way, primarily resulting from the influence of both idiosyncrasies in animal movement and measured and unknown micro‐site characteristics. We recommend spatial replication within sites (e.g., small‐scale shifting of cameras or use of multiple stations) should be considered to minimize impacts of relevant micro‐site characteristics, some of which may be difficult to identify.

中文翻译：

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高密度摄像头陷阱网格揭示了跨空间和时间的检测率和捕获率缺乏一致性

来自照相机陷阱的独立照片事件的计数通常用于推断物种的占有率，未标记种群的密度以及物种在时间和空间上的相对丰度。这些应用基于未经测试的假设，即从单个摄像机收集的数据代表放置它们的风景位置，并且考虑到任何其他微站点差异，附近的摄像机也会记录类似的数据。我们在美国弗吉尼亚州建立了一个高密度摄像头捕获网格（100×100 m； 27个摄像头），以明确检验这些假设，在四个为期两个月的季节性调查中调查了一系列陆生哺乳动物的捕获率和检测概率的变化。尽管控制了许多栖息地和安置因素，但我们记录了 在所有5个重点物种中，捕获率和检测概率的范围和变异系数都很大，这与从更大，更典型的相机陷阱采样设计中的两组独立森林采样点看到的相似。我们还记录了在任何距离下捕获率都缺乏空间自相关。与摄像机视域相关的测量局部协变量（茎密度，摄像机高度，对数存在，有效检测距离[EDD]，橡树总dbh）很少解释观察到的整个网格捕获率或检测概率变化的重要部分。EDD的影响在这里是首次对单个摄影台进行测量，它的重要性并不一致，并且影响的方向取决于物种和季节。我们的研究表明，单摄像机站点可能无法以健壮和可重复的方式对动物的存在和使用频率进行采样，这主要是由于特质对动物运动以及已测量的和未知的微场所特征的影响。我们建议应考虑站点内的空间复制（例如，摄像机的小规模移动或使用多个站点），以最大程度地减少相关微站点特征的影响，其中一些可能很难识别。