The role of food, predation, and population density on the stress physiology of Arctic ground squirrels
grantor: University of Toronto I examined how food, predation and population density interact to compromise the stress response of Arctic ground squirrels (Spermophilus parryii plesius) in the Yukon during the low phase of the snowshoe hare cycle. Squirrels in the boreal forest were sampled from con...
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| Format: | Thesis |
| Language: | English |
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1998
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| Online Access: | http://hdl.handle.net/1807/12422 http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ34102.pdf |
| Summary: | grantor: University of Toronto I examined how food, predation and population density interact to compromise the stress response of Arctic ground squirrels (Spermophilus parryii plesius) in the Yukon during the low phase of the snowshoe hare cycle. Squirrels in the boreal forest were sampled from control, food supplemented, predator reduced, and predator reduced plus food supplemented treatments and from the alpine (predator reduced environment). Boreal forest adult female and juvenile squirrels from control and food supplemented areas showed no effects of chronic stress, predator reduced adult female and juvenile male squirrels showed marginal effects, and adult female and juvenile predator reduced plus food squirrels showed significant effects. Juvenile females from the predator reduced treatment were anomalous, showing a complete inability to respond adaptively. Alpine juveniles were better adapted to handle stress than were boreal forest juveniles. I conclude that in the boreal forest food limitation resulting from high density directly compromised the ability of ground squirrels to cope with stress but that at this point in the snowshoe hare cycle, predation risk did not. M.Sc. |
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