GPS collar sampling frequency: Effects on measures of resource use
GPS collar sampling frequency: Effects on measures of resource use
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DOI：
10.2111/07-044.1
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发表时间：
2008-03-01
影响因子：
2.3
通讯作者：
Ganskopp, David C.
中科院分区：
文献类型：
--
作者：
Johnson, Dustin D.;Ganskopp, David C.
使用全球定位系统（GPS）项圈进行动物行为研究的一个挑战是选择采样频率以实现预期目标。高数据分辨率（即，频繁采样）是有吸引力的，因为它最大限度地收集行为信息。然而，为了描述长期行为或季节动态，可能需要扩展采样。由于高数据分辨率和采样时间之间存在权衡，我们评估了可变GPS采样间隔对牛使用的牧场比例和每天行驶的距离的影响。这是完成与GPS项圈配置记录牛的位置，每5分钟为15天，在三个829-864公顷的牧场。迭代减少数据以模拟越来越长的GPS记录间隔，从每10分钟一次到每天一次。两种技术被用来衡量牧场的百分比牛访问。第一种方法只计算包含GPS坐标的像素。第二个计数包含坐标和/或顶点之间的线穿过的像素。GPS记录间隔的扩展降低了（P < 0.01）牛访问牧场的比例估计值，其下降率最适合于线和点技术的指数衰减函数（R-2分别为0.93和0.97）。然而，使用线技术和歪曲牛访问的区域时，伴随着较不频繁的采样间隔的空间误差非常大。GPS采样间隔的扩大使牛每天行进的距离每次迭代减少约10%（P < 0.001）。如果旅行走廊或对所获取资源的准确评估是关键问题，则应避免较长的全球定位系统整合间隔，因为它们会传播有缺陷的空间解释。同样，如果精确测量行驶距离至关重要，我们建议使用相对频繁的GPS记录间隔。
A challenge in animal behavior studies using Global Positioning System (GPS) collars is selecting a sampling frequency to accomplish desired goals. High data resolution (i.e., frequent sampling) is appealing, because it maximizes behavioral information garnered. Extended sampling might be needed, however, to describe long term behaviors or seasonal dynamics. Because tradeoffs exist between high data resolution and sampling duration, we evaluated the effects of variable GPS sampling intervals on proportions of pastures used by cattle and distance traveled per day. This was accomplished with GPS collars configured to record cattle positions every 5 min for 15 d in three 829-864-ha pastures. Data were iteratively reduced to simulate increasingly longer GPS recording intervals from once every 10 min up to once daily. Two techniques were used to measure the percentage of pastures accessed by cattle. The first counted only pixels containing GPS coordinates. The second counted pixels containing coordinates and/or traversed by lines between vertices. Expansion of GPS recording intervals decreased (P < 0.01) estimates of the proportion of pastures visited by cattle with rates of decline best fit by exponential decay functions for both line and point techniques (R-2 = 0.93 and 0.97, respectively). Spatial errors accompanying less frequent sampling intervals, however, were extremely large with the line technique and misrepresented areas visited by cattle. Expansion of GPS sampling intervals decreased (P < 0.001) distance traveled per day by cattle about 10% with each iteration. If travel corridors or accurate assessments of resources accessed are of critical concern, then longer GPS integration intervals should be avoided because they propagate flawed spatial interpretations. Similarly, if accurate measures of travel distances are critical, we suggest using a relatively frequent GPS recording interval.