| Summary: | 碩士 === 國立成功大學 === 生命科學系碩博士班 === 98 === Juniperus squamata is mainly distributed at high mountains above 3,000 m in Taiwan, including Yushan, Sheishan, and Central Mountain Ranges. It is not only the highest distributed conifer species but also an element of 2nd succession pioneer species at alpine areas in Taiwan. In the past few years, global warming has increased the average temperature gradually, and this climate change may have impacted the populations of J. squamata. The conservation of these alpine species has become an important issue now. Past studies mostly focused on systematics of J. squamata, while very few studies were on the population genetics of J. squamata. In this study, the genetic variation within and between 10 populations of J. squamata was examined with 12 microsatellite loci. The population genetic diversity ranged from 0.675 to 0.876. Demographic analyses revealed that all regional populations remain constant in size. No significant fluctuations or genetic bottlenecks were detected. Furthermore, AMOVA showed that most genetic variances reside within population (p ＜0.05), resulting in low genetic differentiation (FST = 0.05). Both historical gene flow and long life spans may have contributed to the high genetic variation and low between-population differentiation in J. squamata. STRUCTURE analyses further indicated that all population fragments tended to be connected as a whole over glacial maxima.
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