| 文件类型： |
文章 |
| 所有的著者/提供者： |
Dean E Metter; Robert J Pauken |
| ISSN: | 0045-8511 |
|---|
| OCLC号码： |
483704594 |
| 语言注释： |
English |
| 注意： |
Fig. 1. Northwestern United States, Showing General Range of Ascaphus (Within Spoked Lines). (Sample Locations Listed in Table 1.)
Fig. 2. D<sup>2</sup> Values between Adjacent Populations of Adult Ascaphus. *Non-Significant, All Others Significant at 5% Level. |
| 奖励： |
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摘要：
Ascaphus truei presently shows a disjunct distribution in the north-western United States and appears to have low gene flow between adjacent populations. D<sup>2</sup> values of morphological characters of 17 populations of the species appear to reflect a progressive reduction of gene flow since the Pleistocene. Geologic evidence for changing environments in the area correlates closely with this indication of a contracting range. The range of Ascaphus appears to have been almost continuous across Washington, Oregon, northern Idaho and western Montana during the late Pleistocene with much gene flow occurring. Post-Pleistocene environmental changes have resulted in a progressively contracted range for the genus. The now semi-desert, high area of southcentral Oregon was apparently the last avenue of gene flow for Ascaphus between the Cascade Mountains and inland populations of this frog. The indicated pattern of reduction of gene flow in Ascaphus may be applicable to other vertebrates which show similar discontinuous distributions in the northwest U. S.
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文章 : 英语