Four Cities' Forestry Invasion Risk Assessment Of Alien Plants In Guangdong

The process of global integration breaks the geographic isolation of biology and provides the survive conditions for invasive species, which causes it to spread heavily. So biological invasion has become a common problem that all the countries have to face in sustainable development, further more, it causes a great damage to countries' economy, environment and so on.Guangdong's alien plants issue is serious, and most of them was brought in by means of human conscious or unconscious. This study choosed four places: Shenzhen, Zhongshan, Huizhou and Dongguan, and builds the risk evaluation system of four cities' forestry and verifies it also. At the same time, we made risk evaluation to four places' alien plants by making use of risk evaluation system, and we put forward control strategies and the targeted management measures, what is more, our research can provide data support and theoretical support for the policy-making about ecological security, landscaping, plant introduction, and alien plant propagation. The main conclusions are as follows:1.To make a more detailed research and analysis about the current situation of alien plants of Shenzhen, Zhongshan, Huizhou and Dongguan four places, and compile the list of alien invasive plants about four cities' forestry that records in total 192 kinds of plants, including 48 families and 131 genuses.2.From the part of introduction, adaptation, diffusion, characteristics and the life story of plant self, we build a multi levels and multi indexes comprehensive evaluation system, and a forestry risk evaluation index system of alien invasive plants in four cities. The evaluation index system includes “already existing” and “non-introducing”, which has 6 indexes in level one and 12 in level two and 33 in level three. And we made use of analytic hierarchy process to calculate the risk evaluation system about different levels and indicators of weight value.3.We selected 50 typical and different damage level alien invasive plants, and the experimental result shows that assessment system is very scientific and operable under the two conditions of “already existing” and “non-introducing”. Besides, according to the result, we determine risk grade score of three alien invasive plants, and put forward the corresponding strategies for the three levels of risk.4.According to the forestry risk evaluation index system about alien invasive plants of four cities in Guangdong province, we evaluate the 192 kinds of invasive plants under the condition of “already existing”, and classify risk grades by the determined grading standards. Among the invasive plants, the first level of risk has 62 species, the second has 63 species and the third has 67 species. The results of assessment consistent with actual situations. Plants score higher while score lower have the great potential hazard and should be cautious, and increase monitoring efforts and precautions in future introducing and managing work.5.Based on the above analysis and evaluation about the risk of alien invasive plants, we put forward the corresponding preventing and controlling proposals and management measures to alien invasive plants. The prevention works of biotic intrusion, not only need to strengthen inspections of alien plants, but also build the mechanism of participation of all people, and further improve the risk evaluation system.