Document Detail
Aquatic and terrestrial foraging by a subarctic herbivore: the beaver
Abstract/OtherAbstract :
Freshwater and terrestrial ecosystems are tightly linked by food web interactions. Naturally occurring carbon and nitrogen stable isotopes provide a tool to quantify nutrient flows across ecological boundaries, however their application to freshwater-terrestrial systems has been limited. This thesis evaluated whether stable isotope analysis can be effective in differentiating freshwater and terrestrial vascular plants at the base of subarctic food webs and found freshwater plants to be consistently enriched in their isotopic signatures relative to terrestrial plants. Stable isotope approaches were then used to investigate spatial and temporal variability in the diet of a population of subarctic beavers (Castor canadensis). Freshwater macrophytes contributed more to the diets of beavers than previously reported. During the winter, beavers from pond habitats consumed more aquatic vegetation than beavers from stream habitats which relied more heavily on food hoards of terrestrial vegetation. Aquatic foraging may enable beavers to persist at the northern periphery of their range by reducing foraging pressure on the subarctic terrestrial ecosystem where their preferred tree species are scarce.
Authors :
Milligan, Heather
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Contributors :
Murray Mitchell Humphries (Supervisor)
Publication Detail :
Publisher :  McGill University     Type :  Electronic Thesis or Dissertation     Format :  application/pdf    
Date Detail :
2009
Subject :
Biology - Ecology
Coverage :
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Relation :
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Source :
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Copyright Information :
© Heather Milligan, 2009
Other Details :
Languages :  en    
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