Abstract:

The invasiveness or actual dispersal extent and ecological impacts were emphasized in the system to assess the invasion risk of alien woody plant. The assessing process was designed as follows: First of all, the invasiveness or actual spreading amplitude of alien woody plant and ecological impacts were investigated by answering a questionnaire. Then the invasion risk was evaluated according to a synthetic judgment table. Finally management strategy could be developed according to the invasion risk classes and its difficulty in controlling the invasion. Invasiveness assessment was implemented by evaluating its reproduction, dissemination and adaptation ability. Natural reproduction, the invaded plant community types and dissemination speed were taken into consideration in the evaluation of actual dispersal extent. The influence of alien woody species on environmental factors, structure and function of plant community and on local genetic integrality and nutrition chain in the ecosystem were included in ecological impact indicators. The difficulty in controlling the invasion was related with influencing control factors, control method and the adverse impact on environment.

Key words: alien woody plant, invasion risk assessment, indicator