Pollen dispersal patterns and population persistence in a small isolated population of Fagus crenata

The potential of long-distance pollen dispersal and the effects of small population size and population isolation on persistence of Fagus crenata populations were investigated in a small, severely isolated population (the Gofuku-ji population) and two other populations located within 7 km of this population (including 87 adult trees in total). Parentage analysis using 13 microsatellite loci showed that 94 of 100 seedlings derived from seeds collected from the Gofuku-ji population had parent pairs within this population, six had one parent within the population, and four of the six seedlings had alleles that were not detected in any of the three populations, indicating that some pollen is dispersed over distances exceeding 7 km. The estimated expected heterozygosity and effective population size were lower in the Gofuku-ji population than in previously examined large continuous populations. Therefore, levels of genetic diversity within the population may have been reduced by strong genet...本研究以一个严重隔离的小型日本山毛榉（Fagus crenata）种群（五福寺种群，Gofuku-ji population）以及该种群周边7公里范围内的另外两个种群为研究对象，所有研究种群总计包含87株成年个体，旨在探究长距离花粉传播的潜力，以及小型种群规模与种群隔离对日本山毛榉种群存续的影响。通过13个微卫星位点（microsatellite loci）开展亲权分析（parentage analysis），结果显示：从五福寺种群收集的种子萌发得到的100株实生苗中，94株的亲本对均来自该种群内部，6株仅拥有1个亲本来自该种群；其中6株实生苗中有4株携带了在上述三个种群中均未检测到的等位基因，这表明存在部分花粉传播距离超过7公里的情况。本研究测得，五福寺种群的预估期望杂合度（expected heterozygosity）与有效种群大小（effective population size）均低于此前已研究的大型连续种群。因此，该种群内的遗传多样性水平可能因强烈的genet...