Five adult male and two adult female lynx were captured and monitored using radio telemetry from 1985-1987 in north central Washington. Researchers based their findings on 362 radiotelemetry locations, 31 captures and sightings, and >5600 km of winter travel by snowmobile and skis.

Results

"Mean home-range size, based on 22-48 locations, was 39 +/- 2 (SD) km2 for the two females and 69 +/- 28 km2 for the five males." (847)

"The mean annual density of adults and kittens over the 2-year period was 2.6 lynx/100 km2." (847)

"Snowtracking showed that lynx crossed open meadows < 100 m in width but did not hunt in these areas." (847)

"Four denning sites were characterized as mature (> 250 years old) stands with an overstory of Englemann spruce, subalpine fir, and lodgepole pine. All denning sites were located on north-northeast aspects, with an average of 40 downfall logs/50 m. Kittens were observed using the down logs for escape cover." (847)

Discussion

"Based on pellet counts, the density of snowshoe hares was four to five times greater in the 20-year-old stands than the older (43 or > 82 year-old) stands of lodgepole pine and nine times greater than Engelmann spruce-subalpine fir stands." (848)

"Productivity was low during the study, with zero to four kittens present during the winters 1985-1987, and zero to two kittens present during the winters 1980-1983 (D. Brittell, unpublished data). The low number of kittens produced is comparable to lynx populations at northern latitudes when snowshoe hares were scarce." (849)

"Fire suppression in the past 5 decades has limited the young-aged early successional forests in the study area, as well as in the entire region, as it has in some areas of the Great Lake States (Foz 1978). Early successional forests beneficial to snowshoe hares in the study area resulted from lightning fires and windthrow. These existed as small, isolated islands within the study area and rarely exceeded 1 ha in size...:" (849)

Managing lynx populations and their habitats at southern latitudes

"The vulnerability of lynx to trapping and the influences of trapping on lynx survival rates is shown by the high mortality rates (50-90%) in areas where lynx were harvested (Mech 1980; [other cites follow]... compared with the low mortality rate (0-27%) in the study area where lynx were protected. In addition, trapping females accompanied by kittens would result in orphaned kittens possibly dying from starvation (Carbyn and patriquin 1983). During periods of prey scarcity, lynx populations may become increasingly vulnerable to exploitation as they abandon home-range areas in search of prey (Ward and Krebs 1985). This has also been demonstrated for marten (Thompson and Colgran 1987)." (850)

"There are no large unexploited population centers of lynx that could act as a reservoir from which animals might immigrate into the study area. Only 350 km2 of potential habitat (based on GIS inventories of lodgepole pine, Englemann spruce, and subalpine fir forests) occurs in protected adjacent areas, supporting fewer lynx than were found in the study area where there was 570 km2 of habitat. British Columbia likely provides the largest contiguous area of habitat for lynx adjacent to the study area, but timber harvesting and trapping there may limit immigration of lynx into the study area." (850)

"... forest management would require that (i) the number and sizes of openings be limited, (ii) early successional forests as habitat for prey be encouraged, and (iii) mature forest be protected for denning habitats." (850)