Population genetic structure and reproductive strategy of the introduced grass Centotheca lappacea in tropical land-use systems in Sumatra

Intensive transformation of lowland rainforest into oil palm and rubber monocultures is the most common land-use practice in Sumatra (Indonesia), accompanied by invasion of weeds. In the Jambi province, Centotheca lappacea is one of the most abundant alien grass species in plantations and in jungle rubber (an extensively used agroforest), but largely missing in natural rainforests. Here, we investigated putative genetic differentiation and signatures for adaptation in the introduced area. We studied reproductive mode and ploidy level as putative factors for invasiveness of the species. We sampled 19 populations in oil palm and rubber monocultures and in jungle rubber in two regions (Bukit Duabelas and Harapan). Amplified fragment length polymorphisms (AFLP) revealed a high diversity of individual genotypes and only a weak differentiation among populations (FST = 0.173) and between the two regions (FST = 0.065). There was no significant genetic differentiation between the three land-use ...在印度尼西亚苏门答腊岛，低地雨林被大规模改造为油棕与橡胶单一栽培林是当地最主流的土地利用方式，这一过程伴随杂草入侵。在占碑省，铺地黍（Centotheca lappacea）是人工林与丛林橡胶林（一种广泛应用的农林业经营模式）中最为常见的外来草本物种之一，但在天然雨林中几乎不见踪迹。本研究针对该物种在入侵区域内的潜在遗传分化与适应信号展开探究，并将繁殖方式与倍性水平作为该物种入侵性的潜在影响因子进行分析。研究团队在武吉杜亚别拉斯与哈拉潘两个区域的油棕单一栽培林、橡胶单一栽培林及丛林橡胶林中共布设了19个种群采样点。扩增片段长度多态性（Amplified Fragment Length Polymorphisms, AFLP）分析结果显示，该物种的个体基因型多样性较高，但种群间（遗传分化系数FST=0.173）以及两个区域间（FST=0.065）的遗传分化程度均较弱。三种土地利用类型之间未检测到显著的遗传分化……