Browsing by Author "Terwilliger, Lauren"

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    Canada lynx (Lynx canadensis) in Minnesota: Road Use and Movements within the Home Range
    (University of Minnesota Duluth, 2012) Terwilliger, Lauren; Moen, Ronald
    Responses of Canada lynx (Lynx canadensis) to linear corridors, particularly roads and trails, depend on geographic area, individual lynx, road characteristics and local habitat. Roads and trails may benefit lynx by increasing both the ease and speed of travel between use areas. However, proximity to roads may increase the probability of lynx-human interactions and the risk of mortality from vehicle collisions and incidental human-caused mortality. In Minnesota, lynx frequently travel along and cross roads and trails, and proximity to road features occurs both within home ranges and during long-distance movements outside of established territories. The use of linear features by lynx was assessed within seasonal home ranges based on about 4,500 GPS locations from 7 lynx collected during a 6 year radiotelemetry study in the Superior National Forest. Within home ranges, lynx were closer to roads than both water or wetland features, and about 3% of locations occurred on roads/trails. As expected, male lynx had faster movement rates and larger home ranges than female lynx. Although the sample size was small preventing statistical analysis, movement rates were faster for consecutive locations on a road/trail than locations not on a road/trail for female lynx, but similar for male lynx. Distance to roads/trails decreased with increasing road density; however movement rate was not affected by road/trail density which was similar among individuals, home ranges and seasons. Road crossings were also not related to road density, and were proportionate to the total length of various road surface types present within a home range. Finally, distance to roads/trails did not differ between actual locations and random locations. This suggested that lynx were not selecting for or against roads within their home ranges, although within 25 m of a road/trail lynx were closer to roads than random expectation. It appears that the consistent road density across the study area (< 2 km/km2) may account for the lack of relationship between road density and lynx use of roads. It is also probable that lynx use roads/trails within home ranges for more than just movement, potentially foraging along road corridors. Interactions with prey, and encounters with human activities, vehicles and competitors near roads and trails likely explains why movement rates were not increased by road/trail presence. The frequency of lynx occurrence near roads within the home range and during long-distance movements indicates that lynx in Minnesota are occasionally vulnerable to mortality associated with roads. The extent of this potential threat to lynx in Minnesota is unknown.
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    Using GPS Radiotelemetry Locations to Interpret Road and Trail Use by Canada Lynx (Lynx canadensis) in Minnesota
    (2016-12) Terwilliger, Lauren
    The continental United States, including Minnesota, represents the southern extent of the Canada lynx (Lynx canadensis) range. Based on 6 years of radiotelemetry data for lynx in the Superior National Forest, I examined methods for addressing data gaps common to GPS monitoring of free-ranging animals, and examined the use of road infrastructure by lynx within their home ranges. I found that the midpoint between successful locations more accurately estimated the position and cover type of missed locations than imputation using known movement angles and distances. Based on 4,500 GPS locations from 7 individuals, I also found that 3% of lynx locations within seasonal home ranges occurred on roads and trails and lynx crossed road features about 3 times/day. When compared to random locations, lynx were not closer to road infrastructure at the home range scale, but may have been selecting for road infrastructure within 50 m of road features.