2008-06-12_GENERAL DOCUMENTS - C1980007 (3)

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beyond identified home range boundaries, but returning to the original home range. Distances of exploratory movements in Montana ranged from about 15 km (9 miles) to 40 km (25 miles), and duration awav from the home range was 1 week to several months (Squires and Laurion 2000). This type of movement was not detected during the study in north central Washington (Koehler • 1990), nor has it been recorded from the taiga (Mowat et al. 2000). Aubry et al. (2000) speculated that these movements might be more likely to occur in areas with high spatial heterogeneity, especially montane systems. Daily movement distances vary. Ward and Krebs (1985) documented an increase in daily cruising radius from 2.7 km (1.6 miles) during moderate to high hare densities, to 5.4 km (3.2 miles) during low hare densities (<0.5 hares/ha or <0.2 hares/acre). Parker et al. (1983) reported a female's daily cruising distance as 8.8 km (5.3 mi) in winter and 10 km (6 mi) in summer. In the taiga, both adult and subadult lynx are known to make long-distance movements during periods of prey scarcity; recorded distances have been up to 1,000 km (600 miles) (Meth 1980, Slough and Mowat 1996, Poole 1997). During dispersal, the minimum daily travel rate was 1.7 to 8.3 km (1-5 miles) per day (n=3) (Ward and Krebs 1985), suggesting dispersing lynx do not travel farther per day than resident lynx (Mowat et al. 2000). There have been no successful dispersals (where breeding has been documented after moving to a new location) in the southern part of the range (Aubry et al. 2000). Dispersal distances in southern boreal and montane forests are similar to those from the Canadian taiga. Many of the lynx habitats in the Rocky Mountains occur as islands of coniferous forest surrounded by shrub-steppe habitats. Movement of lynx between these forested habitats is • poorly understood. Lynx have been documented in shrub-steppe habitats adjacent to western boreal forests (within approximately 40 km or 25 miles) during a peak in the jackrabbit population (Lewis and Wenger 1998). It is possible that the occasional availability of abundant alternate prey, such as jackrabbits or Wyoming ground squirrels (Spennophilus elegans), may attract lynx into shrub-steppe habitats. It is not known whether these shrub-steppe habitats are important to lynx persistence at the southern edge of their range, or whether they are only used opportunistically (Ruggiero et al. 2000). Periodically, influxes of dispersing lynx have occurred in the northern United States during lows in the snowshoe hare cycle. There is no evidence that immigrating lynx are able to successfully colonize southern areas (McKelvey et al. 2000b). Nevertheless, connectivity between habitats in Canada and United States may be necessary for the persistence of some southern lynx populations, which if isolated may be too small to sustain themselves over the long term. Interspecific relationships with other carnivores - Buskirk et al. (2000a) described the two major competition impacts to lynx as exploitation (competition for food) and interference (avoidance). Of several predators examined (birds of prey, coyote, gray wolf, mountain lion, bobcat (Lvm rufirs), and wolverine), coyotes were deemed to most likely pose local or regionally important exploitation impacts to lynx, and coyotes and bobcats were deemed to possibly impart important interference competition effects on lynx. Mountain lions were described as interference competitors, possibly impacting lynx during summer and in areas lacking deep snow in winter, or when high elevation snow packs develop crust in the spring. •