| Summary: | Degree: Master of Science Abstract: Human altered landscapes can cause the endangerment or extinction of a species, not only by a direct loss of habitat but by altering predator-prey relationships. Predators can drive prey to extinction when the density of the predator becomes subsidized by another abundant, alternate prey. Such indirect species interactions are termed “apparent competition” and are increasingly being linked to species endangerment. The mechanism behind apparent competition may be differences between the prey species in reproductive success, niche overlap, or differences in ability to escape predation. This study focused on a case of apparent competition between moose (Alces alces), wolves (Canis lupus), and endangered mountain caribou (Rangifer tarandus caribou) in the Columbia Mountains of British Columbia. The southern mountain population of caribou escape predation by residing at high elevations most of the year. However, when moose move into caribou habitat in the summer wolves often follow, exposing caribou to greater predation risk. I examined two hypotheses why moose move into caribou habitat in the summer. First, I examined the hypothesis that human-caused early-seral vegetation available in mountain caribou summer habitat attracts moose. I examined this hypothesis using four predictions: i) moose forage will be more abundant in high-elevation cutblocks compared to other habitats at high and low elevations, ii) moose preferentially select for cutblocks at high elevation relative to low-elevation cutblocks, iii) when moose are at high elevations they will be closer to cutblocks than would be expected by random, iv) the amount of cutblocks at high elevations in a moose home range will be positively related to the amount of time moose spend at high elevations. I found my second prediction was supported; moose did select for cutblocks at high elevations. However, the remaining predictions were not supported: moose forage was not more abundant in high-elevation cutblocks, moose at high ...
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