Spread of the exotic croftonweed (Eupatorium adenophorum) across southwest China along roads and streams

Roads and streams are important conduits for the spread of invasive species, and croftonweed is an invasive plant in southwest China. We established six transects along one road and stream in Huili County, Sichuan Province to determine the pattern of invasion and identify major factors potentially influencing it. Results dernonstrated that the invasion (cover, abundance, and number of clusters) of croftonweed declined significantly with distance from the road and stream. However, after compensation for environmental factors, only distance from the road was significantly negatively related to number of clusters of this plant. Instead, native plant species cover and richness were significantly negatively associated with croftonweed invasion along the road; elevation and native species cover were negatively correlated with the invasion along the stream. These findings indicated that roads and streams were main conduits for the spread of croftonweed in southwest China, and reduced native species cover could facilitate invasion by croftonweed. in habitats along roads and streams.