Population dynamics of Clethrionomys and Peromyscus in southwestern Yukon 1973-1989
| Autor: | B. Scott Gilbert, Charles J. Krebs |
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| Rok vydání: | 1991 |
| Předmět: | |
| Zdroj: | Ecography. 14:250-259 |
| ISSN: | 1600-0587 0906-7590 |
| DOI: | 10.1111/j.1600-0587.1991.tb00659.x |
| Popis: | Clethrionomys ruiilus and Peromyscus maniculaius occur together in the boreal forest of southwestern Yukon and we studied their population dynamics on unmanipulated live-trapping grids for 17 yr. Peromyscus showed a regular seasonal change in numbers each year with little interannual variation. Clethrionomys by comparison, showed low density fluctuations during one period (1976-1982) followed by changes in number in the next period that are consistent with a typical 3-4 yr microtine cycle. During one of two years of peak numbers adult males had unusually heavy body weights. The sexual maturation of juvenile Clethrionomys varied inversely with density. In most years Clethrionomys showed higher rates of population increase from spring to late summer than Peromyscus and this may be partly attributed to the vole's longer breeding season. Juvenile female Clethrionomys often reached sexual maturity during their first summer when population density was low but Peromyscus never matured during their first summer. Finally, there was no correlation between the two species in year to year changes in overwinter survival rates. This is the first report of a cyclic Norh American population of Clethrionomys and it underlines the need to search for hypotheses of population regulation that explain both annual and multi-annual cycles within the same population. |
| Databáze: | OpenAIRE |
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