Invasion process and potential spread of Amaranthus retroflexus in China

• Published in: Weed research 2018-02, Vol.58 (1), p.57-67
• Main Authors: Qin, Z, Zhang, J‐E, Jiang, Y‐P, Wei, H, Wang, F‐G, Lu, X‐N, Clements, David
• Format: Article
• Language: English
• Subjects: Amaranthus retroflexus; common amaranth; Ecological monitoring; Ecological niches; invasive species; range changes; Range extension; reciprocal comparison; redroot pigweed; species distribution model
• ISSN: 0043-1737; 1365-3180
• DOI: 10.1111/wre.12282

Summary Amaranthus retroflexus, a troublesome agricultural weed native to North America, has expanded its distribution in large areas of China since its introduction around 1905. Geographical interpretation of changes in their distribution ranges could provide valuable insights on its spatiotemporal invasion patterns and could be used to predict the extent of its future spread. Based on compiled historical distribution occurrences of A. retroflexus in North American and Chinese ranges, invaded ecological niche models for three hypothetical invasion stages were developed. Native models on the basis of all available records within the North American range were also generated for reciprocal comparison with the invaded model. Climate similarity between native and invasive ranges was also investigated. Amaranthus retroflexus has exhibited a rapid and large range expansion after about a 50‐year lag, especially in central and western China. It established a relative stable distribution in the 1960s and has been undergoing a more continuous westward expansion since then. Presently A. retroflexus has not yet reached full occupancy of suitable habitats in China. The results highlight prioritising habitats in south‐western China for monitoring and control to prevent its further spread.