關渡草澤地之巢鼠族群生態及遺傳結構

Population Ecology and Genetic Structure of Harvest Mice (Micromys minutus) in Guandu Salt Marsh

姜壽嶽(Show-Yueh Jiang)

指導教授 ： 林雨德

國立臺灣大學/生命科學院/生態學與演化生物學研究所/碩士(2008年)

https://doi.org/10.6342/NTU.2008.03114

摘要

台北市立關渡自然公園提供了巢鼠(Micromys minutus)不同品質的棲地類型棲息。本研究目的為探討：(1) 棲地演替是否會影響巢鼠之族群遺傳結構 (2) 巢鼠族群波動如何影響巢鼠之族群遺傳結構。研究樣區區分為密生、疏生以及疏密混生的棲地類型，而巢鼠較偏好密生的棲地類型；然而在2000年至2005年間棲地的演替使得樣區內密生棲地的面積大幅下降，造成巢鼠偏好棲息的棲地面積減少且分佈破碎化。雖然密生棲地的分布在2000年至2005年間造成巢鼠分佈破碎化，但其遺傳結構在空間上並無明顯的分化。而在2000及2005年皆由M-ratio偵測到族群曾歷經瓶頸效應，而mode-shift及異型合子偏高此兩方法皆未偵測到瓶頸效應，顯示瓶頸效應並非發生於近期，而是更早的歷史事件造成此兩年皆偵測到瓶頸效應。在年內則由於夏季的族群低點，造成2005年的夏季前後的族群有顯著的遺傳上的分化。綜合以上結果，關渡草澤地的棲地演替會在短時間內造成巢鼠族群在空間上以及時間上的遺傳結構變化。

關鍵字

瓶頸效應 ； 棲地異質性 ； Micromys minutus ； 微隨體基因座 ； 族群波動 ； 族群遺傳 ； 演替

並列摘要

The Guandu salt marsh in the Guandu Nature Park (Taipei, Taiwan) offered habitat patches of different qualities for the harvest mouse (Micromys minutus). The current research aimed to find out (1) if succession could influence the genetic structure of the harvest mouse and (2) how population dynamics affected the genetic structure of the harvest mouse. Study site were categorized into dense, sparse, and mix patches. Dense patches were preferred by Micromys minutus. However, the overall area of dense patches decreased greatly during the succession occurred between 2000 and 2005. The decrease of dense patches not only reduced but also fragmented the habitats suitable for the harvest mouse. The harvest mouse population was fragmented along with dense patches, yet the population did not become structured genetically with significance. I detected bottleneck effect with M-ratio(M<0.68) but not mode-shift and heterozygosity excess in both year, which indicated that bottleneck probably occurred in the past distant enough that the signature of bottleneck detectable by mode-shift and heterozygosity excess has been erased. Within each year, population size became very low in summer, and the genetic differentiation was significant between spring and autumn population in 2005. Overall, the results suggest that salt marsh succession can influence the genetic structure of the harvest mouse in Guandu salt marsh spatially and temporal in a short period of time.

並列關鍵字

bottleneck ； habitat heterogeneity ； Micromys minutus ； microsatellite ； population dynamics ； population genetics ； succession

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