Naturalization of alien plants in China

Naturalization (the establishment of a self-sustaining population for at least a decade) is a fundamental precondition for plant invasion and so compiling a complete inventory of naturalized alien species is necessary for predicting and hence preventing such invasion. However, nationwide information on naturalized plants in China is still lacking. We compiled a nationwide list of the naturalized plant species of China, based on various literature reports. The list comprised a total of 861 naturalized plant species belonging to 110 families and 465 genera. The three most dominant families were Compositae, Poaceae, and Leguminosae, accounting for 16, 13 and 12% of naturalized plants, respectively. Among genera, Euphorbia and Solanum had the most naturalized species, followed by Ipomoea, Amaranthus, Oenothera, and Trifolium. Over half of all aliens were of American origin (52%), followed by those with European (14%) and Asian (13%) origins. Annuals and perennial herbs were prevalent among naturalized species; comparison to other studies suggests however that the invasive potential is higher among plants with longer life cycles than those of annuals. The taxonomic pattern of plant naturalization in China is similar to patterns worldwide. However, the low proportion of naturalized plants within the Chinese flora overall suggests that the potential for plant invasions in China may be high. Therefore, greater attention should be focused on naturalization of alien plants in China, especially concerning species of dominant families or genera, and those with a perennial life cycle.