Diffusion pattern of alien invasive plants along Coastal Highway in Liaoning, China

Highway is one of main ways for alien invasive plant dispersal, and the influences of highway on invasive species are more and more concerned by the road ecologists. However, understanding diffusion pattern and invasive mechanism of alien species is the precondition of effective control of their invasion. Line transect method was employed to have an investigation to 4 kinds of wetland types along coastal highway in Liaoning, China. 25 alien invasive species were found. The research indicates that on the gradient from the near to the distant from the highway: (1) richness of invasive plants presents the pattern of first increasing and then decreasing. (2) the frequency of most invasive species at the boundary of highway is significantly higher than that in distant area; some invasive species choose specific wetland types and invade adjacent land; (3) through analyses of standard deviation of important values, some species show great adaptation and strong invasiveness. These pattern indicates that environmental gradient along the highway generates significant influence on plant invasion; It is believed that the species diffusing along the highway generally can adapt the environment at the boundary of highway; while the species diffusing vertically to the highway cannot just adapt coastal wetland environment, but also own strong dispersal ability.