Document Detail

Of lemmings and snowshoe hares: the ecology of northern Canada.
MedLine Citation:
PMID:  20980307     Owner:  NLM     Status:  MEDLINE    
Two population oscillations dominate terrestrial community dynamics in northern Canada. In the boreal forest, the snowshoe hare (Lepus americanus) fluctuates in cycles with an 8-10 year periodicity and in tundra regions lemmings typically fluctuate in cycles with a 3-4 year periodicity. I review 60 years of research that has uncovered many of the causes of these population cycles, outline areas of controversy that remain and suggest key questions to address. Lemmings are keystone herbivores in tundra ecosystems because they are a key food resource for many avian and mammalian predators and are a major consumer of plant production. There remains much controversy over the role of predation, food shortage and social interactions in causing lemming cycles. Predation is well documented as a significant mortality factor limiting numbers. Food shortage is less likely to be a major limiting factor on population growth in lemmings. Social interactions might play a critical role in reducing the rate of population growth as lemming density rises. Snowshoe hares across the boreal forest are a key food for many predators and their cycles have been the subject of large-scale field experiments that have pinpointed predation as the key limiting factor causing these fluctuations. Predators kill hares directly and indirectly stress them by unsuccessful pursuits. Stress reduces the reproductive rate of female hares and is transmitted to their offspring who also suffer reduced reproductive rates. The maternal effects produced by predation risk induce a time lag in the response of hare reproductive rate to density, aiding the cyclic dynamics.
Charles J Krebs
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Review     Date:  2010-10-27
Journal Detail:
Title:  Proceedings. Biological sciences / The Royal Society     Volume:  278     ISSN:  1471-2954     ISO Abbreviation:  Proc. Biol. Sci.     Publication Date:  2011 Feb 
Date Detail:
Created Date:  2011-01-12     Completed Date:  2011-05-04     Revised Date:  2013-07-03    
Medline Journal Info:
Nlm Unique ID:  101245157     Medline TA:  Proc Biol Sci     Country:  England    
Other Details:
Languages:  eng     Pagination:  481-9     Citation Subset:  IM    
Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, British Columbia, Canada , V6T 1Z4.
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MeSH Terms
Arvicolinae / physiology*
Food Chain
Hares / physiology*
Population Density
Population Dynamics
Predatory Behavior / physiology*
Reproduction / physiology
Stress, Physiological / physiology

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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