Seasonal forcing on the dynamics of Clethrionomys rufocanus: Modeling geographic gradients in population dynamics

Abstract We interpret gradients in population dynamics of the gray‐sided vole from the southwestern part of the island of Hokkaido to its northeastern part within the framework of a phenomenological model involving the relative length of summer and winter. In Hokkaido, as in other northern regions,...

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Bibliographic Details
Published in:Population Ecology
Main Authors: Stenseth, Nils Chr, Bjørnstad, Ottar N., Saitoh, Takashi
Format: Article in Journal/Newspaper
Language:English
Published: Wiley 1998
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Online Access:http://dx.doi.org/10.1007/bf02765224
https://onlinelibrary.wiley.com/doi/pdf/10.1007/BF02765224
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Summary:Abstract We interpret gradients in population dynamics of the gray‐sided vole from the southwestern part of the island of Hokkaido to its northeastern part within the framework of a phenomenological model involving the relative length of summer and winter. In Hokkaido, as in other northern regions, both spring and fall is considered as short transition periods between the two main seasons — summer (the primary breeding season) and winter (the non‐reproductive or secondary breeding season). We show that the geographic transition in dynamics may be understood as the combined consequence of different patterns of density‐dependence during summer and winter, and geographically varying season lengths. Differences are shown to exist between summer and winter with respect to strength of density‐dependence. Direct density‐dependence, in particular, is stronger during winter than during summer. A model is presented to show how relative lengths of seasons can induce both stable and periodically fluctuating population dynamics. The results are compared and contrasted with what is otherwise known about the gradient in rodent dynamics in Fennoscandia.