Invasion dynamics and potential spread of the invasive alien plant speciesAgeratina adenophora(Asteraceae) in China

Abstract

ABSTRACTAgeratina adenophora(Sprengel) R. King & H. Robinson (=Eupatorium adenophorumSprengel) is one of the worst invasive alien species in China. SinceA.adenophorawas first noticed in Yunnan Province of China in the 1940s, its rapid spread has caused an ecological problem in south‐western China. Understanding its historical invasion pattern and its potential for further spread is needed to plan the management of the species. We reconstructed the historical process of its invasion and analysed its ecological preferences in the invaded region. After a lag phase of 20 years (1940–60),A.adenophoraspread rapidly throughout the south and middle subtropical zones in Yunnan, Guizhou, Sichuan, and Guangxi, China, with an average expansion rate of 20 km per year. It spread relatively slowly in north subtropical areas, with an average expansion rate of 6.8 km per year. It has not established in warm temperate areas within the invaded regions. Although range expansion in Yunnan stopped after 1990, the expansion of its range into neighbouring provinces indicates thatA.adenophorahas not reached the full potential of its distribution and its range is still rapidly expanding within China. We applied ecological niche modelling (GARP — Genetic Algorithm for Rule‐set Prediction) to predict potential invasion areas in mainland China on the basis of occurrence points within colonized areas whereA.adenophorahas reached equilibrium. The predictions, confirmed by the range of values of four key environmental parameters, generally match the parameters of the geography and ecology in the invaded region. Southern and south‐central China have climatic conditions suggestive of a high potential for invasion byA.adenophora. Climatic conditions in northern and western China appear unsuitable forA.adenophora. Urgent measures should be taken to prevent this species from further spreading into the vast areas of potential habitat in southern and south‐central China.