title: The Relative Importance of Genetic Diversity and Phenotypic Plasticity in Determining Invasion Success of a Clonal Weed in the USA and China.
abstract: Phenotypic plasticity has been proposed as an important adaptive strategy for clonal plants in heterogeneous habitats. Increased phenotypic plasticity can be especially beneficial for invasive clonal plants, allowing them to colonize new environments even when genetic diversity is low. However, the relative importance of genetic diversity and phenotypic plasticity for invasion success remains largely unknown. Here, we performed molecular marker analyses and a common garden experiment to investigate the genetic diversity and phenotypic plasticity of the globally important weed Alternanthera philoxeroides in response to different water availability (terrestrial vs. aquatic habitats). This species relies predominantly on clonal propagation in introduced ranges. We therefore expected genetic diversity to be restricted in the two sampled introduced ranges (the USA and China) when compared to the native range (Argentina), but that phenotypic plasticity may allow the species' full niche range to nonetheless be exploited. We found clones from China had very low genetic diversity in terms of both marker diversity and quantitative variation when compared with those from the USA and Argentina, probably reflecting different introduction histories. In contrast, similar patterns of phenotypic plasticity were found for clones from all three regions. Furthermore, despite the different levels of genetic diversity, bioclimatic modeling suggested that the full potential bioclimatic distribution had been invaded in both China and USA. Phenotypic plasticity, not genetic diversity, was therefore critical in allowing A. philoxeroides to invade diverse habitats across broad geographic areas.
authors.affiliation: School of Ecology and Environmental Sciences, Institute of Ecology and Geobotany, Yunnan UniversityKunming, China; Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Institute of Biodiversity Science, Fudan UniversityShanghai, China.
authors.forename: Yupeng
authors.initials: Y
authors.lastname: Geng
authors.affiliation: CSIRO Ecosystem Sciences Brisbane, QLD, Australia.
authors.forename: Rieks D
authors.initials: RD
authors.lastname: van Klinken
authors.affiliation: Fundación para el Estudio de Especies Invasivas Hurlingham, Buenos Aires, Argentina.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Sosa
authors.affiliation: Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Institute of Biodiversity Science, Fudan University Shanghai, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Li
authors.affiliation: Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Institute of Biodiversity Science, Fudan University Shanghai, China.
authors.forename: Jiakuan
authors.initials: J
authors.lastname: Chen
authors.affiliation: School of Medical and Applied Sciences, Central Queensland University Bundaberg, QLD, Australia.
authors.forename: Cheng-Yuan
authors.initials: CY
authors.lastname: Xu
keywords: Alternanthera philoxeroides; common garden experiment; genetic diversity; invasive species; molecular marker; phenotypic plasticity