Predator and prey population dynamics and distribution: effects of predation and competition
LE3 .A278 2001
Master of Science
The landscape in which common weasels ('Mustela nivalis vulgaris '), and field voles ('Microtus agrestis') live and weasel dispersal ability affect population dynamics in Kielder Forest, Northern England. Grassed clear-cuts (the primary habitat for voles and weasels) within Kielder are not 'islands' but in fact habitat patches that are highly connected by linear features. It is possible that the mobility of common weasels in Kielder Forest may cause decreased amplitude of the vole population cycle. Small mustelids should not experience increased energetic cost and/or mortality when dispersing to exploitable patches because they are not moving through unsuitable, non-prey habitat. My findings suggest that connectivity between suitable habitat patches and specialist predator dispersal ability are important variables that require consideration when researching the impact of predators on small rodent dynamics. A bait station database was used to identify carnivore associations in the Cape Breton Highlands, NovaScotia. Carnivore abundance and distribution may be influenced by interference and resource competition. Species association patterns were used to infer interspecific interactions. Red fox (' Vulpes vulpes') were absent from bait stations with either coyotes ('Canis latrans') or lynx ('Felis lynx'). It may be that red foxes were not present in these areas due to different habitat preferences, active avoidance of areas where lynx or coyote are abundant, or high predation of foxes. A positive species association was found for red fox and short-tailed weasel ('Mustela erminea'). This positive association may be the result of high niche overlap between foxes and weasels. It is likely that interspecific interactions, especially interference competition, shape the carnivore community of the Cape Breton Highlands. Further research is required for red foxes, as they may be severely affected by competition.
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