Genetic connectivity of the moth pollinated tree Glionnetia sericea in a highly fragmented habitat

Long-distance gene flow is thought to be one prerequisite for the persistence of plant species in fragmented environments. Human influences have led to severe fragmentation of native habitats in the Seychelles islands, with many species surviving only in small and isolated populations. The endangered Seychelles endemic tree Glionnetia sericea is restricted to altitudes between 450 m and 900 m where the native forest vegetation has been largely lost and replaced with exotic invasives over the last 200 years. This study explores the genetic and ecological consequences of population fragmentation in this species by analysing patterns of genetic diversity in a sample of adults, juveniles and seeds, and by using controlled pollination experiments. Our results show no decrease in genetic diversity and no increase in genetic structuring from adult to juvenile cohorts. Despite significant inbreeding in some populations, there is no evidence of higher inbreeding in juvenile cohorts relative to a...长距离基因流（long-distance gene flow）被认为是植物物种在破碎化生境中存续的必要前提之一。人类活动已导致塞舌尔群岛的本土生境遭到严重破碎化，诸多物种仅能以小型孤立种群存续。塞舌尔特有濒危树种Glionnetia sericea仅分布于海拔450米至900米的区域，该区域内的原生森林植被在近200年间已大面积丧失，被外来入侵物种替代。本研究通过对成年个体、幼龄个体及种子样本的遗传多样性模式进行分析，并结合控制授粉实验，探究该物种种群破碎化带来的遗传与生态后果。研究结果显示，从成年个体群落到幼龄个体群落，该物种的遗传多样性未出现下降，遗传结构也未出现增强。尽管部分种群存在显著的近交现象，但尚无证据表明幼龄同龄群的近交程度相较于a[...]更高。