Abstract: Risk assessment is an effective means to prevent invasive species. In order to evaluate the invasion risk of exotic forages and prevent the ecological security threat caused by blind introduction,this study combined the frequency analysis method with the analytic hierarchy process (AHP) to establish an operable index system for evaluating the invasion risk of alien herbage species. The system was consisted of 5 first-level indicators and 18 second-level indicators,including invasiveness,adaptability,diffusion,harmfulness and controllability of alien plants. Four invasive plants of Gramineae and three non-invasive plants of Gramineae were used to validate the evaluation index system,which was employed to test the rationality of the system. The evaluation system was used to evaluate the invasion risk of switchgrass,and it was concluded that the invasion risk was medium and acceptable,mainly reflected in its strong adaptability and diffusion. The establishment of this evaluation system could provide reference for introduction and management of alien forages.

Key words: Alien forages, Invasive risk, Assessment system

摘要： 风险评估是预防外来物种入侵的有效手段，为科学评价外来牧草的入侵风险，防止盲目引种带来生态安全威胁，本研究将频度分析法与层次分析法结合，建立外来牧草入侵风险评估指标体系；该体系由5个一级指标和18个二级指标组成，包括外来牧草的入侵性、适应性、扩散性、生物学特性、危害性、防除难度等方面；本研究中，利用4种禾本科外来入侵牧草和3种禾本科外来牧草对构建的评估体系进行验证，并利用该体系对外来牧草柳枝稷（Panicum virgatum L.）进行了入侵风险评估实例研究，得出其入侵风险为中等，主要体现在适应性强和扩散性强方面。本研究建立的评估体系，可初步明确柳枝稷入侵风险的主要来源，为外来牧草的引种管理提供参考。

关键词: 外来草种, 入侵风险, 评估体系