Reconstructing changes in the genotype, phenotype, and climatic niche of an introduced species

An introduced species must contend with enormous environmental variation in its introduced range. In this study, we use niche models and ordination analyses to reconstruct changes in genotype, phenotype, and climatic niche of Johnsongrass (Sorghum halepense), which is regarded as one of the world's most threatening invasive plants. In the United States, Johnsongrass has rapidly evolved within- and among-population genetic diversity; our results show that genetic differentiation in expanding Johnsongrass populations has resulted in phenotypic variation that is consistent with habitat and climatic variation encountered during its expansion. Moreover, Johnsongrass expanded from agricultural to non-agricultural habitat, and now, despite occupying overlapping ranges, extant agricultural and non-agricultural populations are genetically and phenotypically distinct and manifest different plastic responses when encountering environmental variation. Non-agricultural accessions are broadly distrib...外来引入物种在其入侵分布区内必须应对极强的环境异质性。本研究利用生态位模型（niche models）与排序分析（ordination analyses），对被列为全球极具威胁性入侵植物之一的约翰逊草（Sorghum halepense）的基因型（genotype）、表型（phenotype）及气候生态位（climatic niche）的变化进行了重建。在美国境内，约翰逊草已快速演化出种群内部及种群间的遗传多样性；研究结果显示，处于扩张过程中的约翰逊草种群所产生的遗传分化，所带来的表型变异与其扩张过程中遭遇的生境与气候波动相契合。此外，约翰逊草从农业生境扩张至非农业生境；如今尽管二者分布范围存在重叠，但现存的农业生境与非农业生境种群在遗传与表型上均存在显著差异，且在应对环境波动时表现出不同的表型可塑性响应。非农业生境居群的分布范围较为广泛……