Bobcat (Lynx rufus) habitat selection and suitability assessment in southeast British Columbia
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AbstractSpatial organization, juvenile dispersal, winter food habits, and winter habitat relationships were examined for bobcats (Lynx rufus) occurring near a range limit in southeast British Columbia. For the period 1990 - 95, resident male and female annual home range size (95% ADK) differed, averaging 199.1 km2 (n = 7) and 64.6 km2 (n = 5) respectively. Home ranges were smaller in winter than in summer for males, but did not differ for females. Annual spatial overlap among neighboring males was extensive, although temporal avoidance was evident. Juvenile males (n = 6) exhibited long-distance dispersal, whereas juvenile females (n = 3) did not. Examination of 70 carcasses collected from throughout the region during winter, 1990 - 95, indicated red squirrels (Tamiasciurus hudsonicus) to be consumed most frequently (52% of stomachs), followed by ungulates (26%), microtine rodents (11 %), and snowshoe hares (Lepus americanus) (7%). Both ungulate consumption and fat index were greater for adult males than adult females or kitten/juveniles. Fat index was lower during the most severe winter for adult females and kitten/juveniles, but not for adult males. Results relate to body size differences among cohorts. Winter selection for most habitat variables was evident at both landscape and stand levels. Bobcats selected terrain characterized by low elevations, moderate slopes, and a proximity to rocky outcrops. Affinity for forest cover attributes was also apparent, particularly mature, multi-layered stands dominated by Douglas-fir, with moderate canopy closure, and large average tree diameter. Variation in selection patterns was evident among individuals and between sexes. Sex-specific multivariate models of winter habitat selection were developed for the study area. Discriminant functions were consistent with univariate results, above, and provided good predictive ability. Applied across the study area using GIS, the models predict the probability that any site represents "winter habitat" for bobcats, and equate to winter habitat suitability. These models may serve as useful management tools, provided that underlying assumptions are recognized. Selectivity analyses for levels of habitat dispersion suggest that bobcats select landscapes that achieve at least 25% "winter habitat" distributed per 75 km². Long-term persistence of bobcats in this region will require habitat management at multiple scales, and recommendations are provided.
Bibliography: p. 111-129.