Get 20M+ Full-Text Papers For Less Than $1.50/day. Start a 14-Day Trial for You or Your Team.

Learn More →

Population dynamics of shrews on small islands accord with the equilibrium model

Population dynamics of shrews on small islands accord with the equilibrium model Three of the six species of shrew in Finland, Sorex araneus, S. caecutiens, and S. minutus, are common on the mainland and widespread on islands in lakes. The islands range from 0.01 to 500 ha in area, and from 10 to 3000 m in isolation (distance from the mainland). The species‐area relationship, the lack of importance of habitat diversity, the increasing frequency of unoccupied small islands with isolation, and direct observations of small populations, all suggest that populations on small islands have a high extinction rate. Demographic stochasticity is the main cause of extinctions in the superior competitor, S. araneus, which occurs consistently on islands greater than 2 ha. The small species, S. caecutiens and S. minutus, are more sensitive to environmental stochasticity than is S. araneus, and are inferior to it in interspecific competition; these factors probably contribute to the absence of the small species from many islands tens of hectares in area. Frequent colonization of islands less than 500 m from the mainland is indicated by large numbers of shrews trapped from tiny islets where breeding is not possible, by increasing epigenetic divergence of island populations with isolation, and by observations of dispersal to and colonization of islands. Dispersal ability decreases with decreasing individual size, which may partly explain the absence of the small shrews from many relatively large islands. The shrew populations persist in a dynamic equilibrium on the islands. Epigenetic morphological variation is a useful tool in ecological studies of island populations. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Biological Journal of the Linnean Society Oxford University Press

Population dynamics of shrews on small islands accord with the equilibrium model

Hanski, Ilkka
Biological Journal of the Linnean Society , Volume 28 (1‐2) – May 1, 1986
Download PDF
14 pages

Loading next page...
 
/lp/oxford-university-press/population-dynamics-of-shrews-on-small-islands-accord-with-the-txQxaW66Tr

References (28)

Publisher
Oxford University Press
Copyright
Copyright © 1986 Wiley Subscription Services, Inc., A Wiley Company
ISSN
0024-4066
eISSN
1095-8312
DOI
10.1111/j.1095-8312.1986.tb01747.x
Publisher site
See Article on Publisher Site

Abstract

Three of the six species of shrew in Finland, Sorex araneus, S. caecutiens, and S. minutus, are common on the mainland and widespread on islands in lakes. The islands range from 0.01 to 500 ha in area, and from 10 to 3000 m in isolation (distance from the mainland). The species‐area relationship, the lack of importance of habitat diversity, the increasing frequency of unoccupied small islands with isolation, and direct observations of small populations, all suggest that populations on small islands have a high extinction rate. Demographic stochasticity is the main cause of extinctions in the superior competitor, S. araneus, which occurs consistently on islands greater than 2 ha. The small species, S. caecutiens and S. minutus, are more sensitive to environmental stochasticity than is S. araneus, and are inferior to it in interspecific competition; these factors probably contribute to the absence of the small species from many islands tens of hectares in area. Frequent colonization of islands less than 500 m from the mainland is indicated by large numbers of shrews trapped from tiny islets where breeding is not possible, by increasing epigenetic divergence of island populations with isolation, and by observations of dispersal to and colonization of islands. Dispersal ability decreases with decreasing individual size, which may partly explain the absence of the small shrews from many relatively large islands. The shrew populations persist in a dynamic equilibrium on the islands. Epigenetic morphological variation is a useful tool in ecological studies of island populations.

Journal

Biological Journal of the Linnean Society – Oxford University Press

Published: May 1, 1986

There are no references for this article.