Origin of the invasive Arundo donax (Poaceae): a trans-Asian expedition in herbaria |
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Authors: | Laurent Hardion Régine Verlaque Kristin Saltonstall Agathe Leriche Bruno Vila |
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Institution: | 1.Institut Méditerranéen de Biodiversité et d''Ecologie, UMR CNRS IRD, Aix Marseille Université, 13331 Marseille, France;2.Smithsonian Tropical Research Institute, Apartado 0843-03092, Panama |
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Abstract: | Background and AimsThe hypothesis of an ancient introduction, i.e. archaeophyte origin, is one of the most challenging questions in phylogeography. Arundo donax (Poaceae) is currently considered to be one of the worst invasive species globally, but it has also been widely utilzed by man across Eurasia for millennia. Despite a lack of phylogenetic data, recent literature has often speculated on its introduction to the Mediterranean region.MethodsThis study tests the hypothesis of its ancient introduction from Asia to the Mediterranean by using plastid DNA sequencing and morphometric analysis on 127 herbarium specimens collected across sub-tropical Eurasia. In addition, a bioclimatic species distribution model calibrated on 1221 Mediterranean localities was used to identify similar ecological niches in Asia.Key ResultsDespite analysis of several plastid DNA hypervariable sites and the identification of 13 haplotypes, A. donax was represented by a single haplotype from the Mediterranean to the Middle East. This haplotype is shared with invasive samples worldwide, and its nearest phylogenetic relatives are located in the Middle East. Morphometric data characterized this invasive clone by a robust morphotype distinguishable from all other Asian samples. The ecological niche modelling designated the southern Caspian Sea, southern Iran and the Indus Valley as the most suitable regions of origin in Asia for the invasive clone of A. donax.ConclusionsUsing an integrative approach, an ancient dispersion of this robust, polyploid and non-fruiting clone is hypothesized from the Middle East to the west, leading to its invasion throughout the Mediterranean Basin. |
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Keywords: | Arundo donax Poaceae invasive species archaeophyte herbarium specimens phylogeography domesticated species Mediterranean Asia morphometry clonal species crops giant reed giant cane |
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