Research PapersGPS Collar Sampling Frequency: Effects on Measures of Resource Use
Section snippets
INTRODUCTION
Global Positioning System (GPS) technology is a relatively recent development (e.g., Rodgers and Anson 1994; Rodgers et al. 1996; Agouridis et al. 2004) for monitoring travel (Brosh et al. 2006), activity (Ungar et al. 2005), and resource use by medium- to large-sized animals (Mourão and Medri 2002; Bailey et al. 2006). GPS receivers in a lightweight collar or harness can be deployed for extended periods with little effect on behavior. Units derive coordinates from an internal receiver tracking
Study Site
Research occurred simultaneously in three pastures (829–864 ha) on the Northern Great Basin Experimental Range (lat 43°29′N, long 119°43′W [WGS-1984 datum]; elevation 1 400–1 674 m), 52 km west of Burns, Oregon. Mean annual temperature is 7.6°C with recorded extremes of -29°C and 42°C. Mean annual precipitation is 289 mm with about 60% being snow.
Vegetation is characterized by a sparse western juniper (Juniperus occidentalis subsp. occidentalis Hook.) overstory and a shrub layer dominated by
GPS Sampling Interval Effects on Percent of Pasture Visited
With a 5-min GPS schedule over a 15-d interval, cattle were found in 286.6 ± pixels · pasture−1 with the point technique and 307.0 ± pixels · pasture−1 with the line method. Pastures averaged 846.6 ± pixels, so cattle visited approximately 33.8 ± 0.5% and 36.3 ± 0.3% of their pastures, respectively, with the point and line methods (Fig. 2).
As GPS sampling intervals were progressively expanded, estimates of the percent of pasture visited by cattle declined with both methods (Fig. 2). The rate of
Discussion
Decisions regarding the resolution and analyses of GPS collar data have profound consequences on the quantity and accuracy of information garnered in animal behavior studies. With expanded GPS sampling intervals, we progressively underestimated pasture use and travel by cattle. In all instances, rate of decline was best fit with exponential decay functions (Figs. 2 and 4).
When estimating the proportion of pastures visited by cattle as GPS recording intervals were expanded, measures declined
MANAGEMENT IMPLICATIONS
Although GPS collars are well proven tools for quantifying resource use, activity patterns, and travels of free-ranging animals, researchers must still address the quandary of memory and battery constraints specific to their instruments. An expansion of our most frequent recording interval of 5 min to 10 min could extend a study duration from 15 to 30 d without exhausting batteries. Misrepresentations of areas occupied would simultaneously increase from about 7% to 10%, respectively, an error
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2022, Ecological IndicatorsCitation Excerpt :Long GPS sampling intervals may lead erroneously interpret the complexity of movements patterns (Codling and Plank, 2011; Plank and Codling, 2011). Optimal GPS sampling intervals for studying herbivore movement patterns range between 5 and 10 min (Johnson and Ganskopp, 2008). We chose 10 min intervals to be the minimal interval that allows recording a length sequence that satisfice our fractal analyses in 15 days intervals.
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2021, Forest Ecology and ManagementLow-Cost Livestock Global Positioning System Collar from Commercial Off-the-Shelf Parts
2019, Rangeland Ecology and ManagementCitation Excerpt :Both Clark et al. (2006) and McGranahan et al. (2018) reported 95% CEP of GPS fixes taken at 1-s intervals. However, because precision of GPS measurements varies with fix interval length (Johnson and Ganskopp, 2008), we first recorded GPS readings at 1-s intervals and then performed a 24-h accuracy test at 5-min fix intervals. We calculated mean displacement and 95% CEP for both intervals.
Human vs robot: Comparing the viability and utility of autonomous underwater vehicles for the acoustic telemetry tracking of marine organisms
2016, Journal of Experimental Marine Biology and EcologyCitation Excerpt :The difference between the UDs highlights one of the benefits of this technology, where the larger 95% UD of the AUV compared to the human tracker demonstrates that the AUV is likely better able to capture quick forays and movements that individuals make expanding the area an individual uses. Thus, the AUV more accurately reflects episodic animal movement and habitats that may be seldom used, while this information is lost due to aliasing with a human tracker (positions every 5–10 min) (Frair et al., 2004; Johnson and Ganskopp, 2008). The AUV also had a substantially smaller 50% core UD than a human tracker, suggesting that the increased temporal resolution of the AUV better reflect the areas and microhabitats where individuals spend the majority of their time (Andrews et al., 2011; Fieberg and Kochanny, 2005).
Eastern Oregon Agricultural Research Center, including the Burns and Union Stations, is jointly operated by the Oregon Agricultural Experiment Station of Oregon State University, Corvallis, Oregon and the United States Dept of Agriculture–Agricultural Research Service.
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