IUCN / SSC Cat Specialist Group - Digital Cat Library |
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| Terwilliger, L.A. | |
| Using GPS radiotelemetry locations to interpret road and trail use by Canada lynx (_Lynx canadensis_) in Minnesota | |
| 2016 Full Book | |
The continental United States, including northeastern Minnesota, represents the southern extent of the Canada lynx (_Lynx canadensis_) range. Legally differentiating them from lynx in Canada and Alaska, lynx within the contiguous U.S. are considered a Distinct Population Segment, and are designated as Threatened under the Endangered Species Act. Due to higher human population densities, larger home ranges, lower prey densities, increased habitat heterogeneity and the fragmented nature of lynx habitat at southern latitudes, the Distinct Population Segment is exposed to human development and infrastructure, and is subject to metapopulation dynamics, both of which may affect persistence of the U.S. lynx population. Based on 6 years of radiotelemetry data for Canada lynx in the Superior National Forest of Minnesota, I examined methods for addressing data gaps common to global positioning system (GPS) telemetry monitoring of free-ranging animals, and examined space use of lynx within their home ranges, particularly their proximity to and use of road infrastructure. Unsuccessful GPS location attempts occur due to various geophysical, environmental and animal characteristics, and although they can influence inferences about resource and space use, are not always addressed in analysis of habitat use, movements and resource selection. Using successful GPS radiotelemetry locations for 7 Canada lynx (4 males and 3 females) separated by 0.5 hr, 1 hr and 6 hr intervals I systematically excluded known locations and tested two methods for interpolating their position. These methods estimated the position of a missed location (1) using displacement distances and movement angles between known locations or (2) as the midpoint between successful location attempts. After comparing the imputed locations to their known counterparts, I found that locations interpolated as the midpoint between successful location attempts more accurately estimated the position and cover type of excluded locations than locations estimated based on paired movement angles and displacement distances. Accuracy of both cover type prediction and position were improved for location attempts separated by a shorter interval and for locations in larger habitat patches. Though locations interpolated as the midpoint between successful locations more accurately predicted cover type and lynx position, especially for shorter intervals between location attempts, success of cover type assignment by this method was 73% and position error was . 95 m. Large variance in the movement angle of a lynx path between locations, potentially irregular habitat borders and patchiness of preferred cover types in the study area, and a likely preference for habitat edges among the study animals, may explain the limited utility of midpoints as replacements for missed locations. |
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