Effects of anthropogenic disturbance on landscape ecology of cougars.

摘要

Anthropogenic disturbance in the form of hunting and human landscape alterations have extensive effects on cougar populations. I analyzed the effects of hunting and related immigration on the social organization of two independent populations of cougars; a source population with low hunting mortality (11%) and a 12% emigration rate, and a sink population with high mortality (24%) and a 13% immigration rate. I compared home range size, 2-dimensional home range overlap, and 3-dimensional utilization distribution overlap index (UDOI) between annual cougar home ranges. Male cougars in the heavily hunted area had 2-3 times larger home ranges, and 2-dimensional and 3-dimensional UDOI overlap-indicating a difference in the social structure in the high mortality area. Females showed no difference in home range size and overlap of home range areas between study populations.;Traditional closed population methods to estimate density may over-estimate numbers of carnivores. I used cougar home range size and overlap to model total (closed) and proportional (open) densities within the 99% composite female range for two sampling areas in Washington. These simulations suggest that traditional closed population estimates may more than double or triple estimates of density and population size. The proportion of time spent by territorial vi animals within a sampling area should be considered when calculating densities of wide-ranging, territorial carnivores.;Understanding the ecology of how cougars respond to human development aids in landscape planning and minimizes negative interactions. I analyzed sex and seasonal differences in use of human occupied areas and identified cumulative percentage of cougar utilization for distance to structures and density of human development. There were no differences in habitat use between sexes. Cougars used lower elevations and steeper slopes during winter, and expanded into higher elevation areas with greater canopy closure during summer. Cougar response to density of human structures was equally negative for both seasons. Only 5% of cougar habitat use occurs in areas where density of human structures exceeds 19.6 structures/km2. I found cougars utilized areas > than 240 m from structures 95% of the time in winter, and >340 m from structures during summer.