Island colonization and peninsulas
In: Oikos (København). Munksgaard: Copenhagen. ISSN 0030-1299; e-ISSN 1600-0706, meer
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| Abstract |
R. J. Taylor (1987) has proposed a mechanistic model of island colonization that incorporates the geometry of source populations on the mainland. The main prediction of his model is that islands off peninsulas have lower immigration rates than islands off straight-line shores. We have tested this prediction with shrews dispersing to small islets in a lake. We found a significant peninsula effect but in direction opposite to Taylor's prediction, apparently because dispersing shrews, and most other animals, do not obey the simple diffusion assumption made in Taylor's model. Dispersing individuals often move along peninsulas and hence peninsulas may have more dispersers per unit length of coast than straight-line shores. We agree with Taylor that the geometry of islands and the mainland should be incorporated in realistic models of island colonization, but so should the behaviour of the dispersers. |
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