The Evaluation About Economic And Environmental Effects Of Alien Plant Invasion

Biological invasion is the phenomenon that biology bring the economic cost and badly harm environmental safety by diffusion. Invasive species contain plant, bacterium, vermin and so on. The diffuse ways are multifarious and impossible to defend effectively. It badly harm the environment where people live, and is one of the three most intractable environmental problem in the world now.China spans 50 latitude & 5 climatic belts, and with a vast territory. This natural character make China invaded easily by the invasive species, so most of the alien species come from any place could be live in China. Since 1980's, the fatalness and risk of alien Biological invasion go with the developments of international trade, tourism and traffic. Some deleterious species which are badly harmful invaded China, diffused and spread in the effect of many factors.China is one of the countries who suffer the most severe invasion of alien species. In their diffusion and spread, Alien invasive species cause huge cost and the loss of biological diversity, even make some species die out. It imperils the health of people and livestock, harm the social sustainable development and safety, and bring some safety problem about politics, economics, society and culture.Firstly, this paper analyzes the others' relevant researches at home and oversea, and pay attention to the study of evaluation about economic and environment effect. Secondly, on the basis of description of status quo about alien plant invasion, it compares and chooses the Spartina and Solidago canadensis L. as the examples. Thirdly, it uses the method of cost-benefit analysis and evaluates about the economic and environmental effect and the cost of preventing and controlling. At last, it draws the following conclusions:1. According to the study of Case1, the direct benefit of Spartina in Jiangsu is 4.16×10~7yuan. Because the loss of the Spartina in Jiangsu isn't enormous and numerical, I estimate the damage of the Spartina farthest and the value is 1.5665×10~7 yuan. But in Fujian, the loss of the Spartina is about 11×10~8yuan and the benefit is 1.8×10~7yuan. This case indicates the same invasive species could cause different impacts in different area, and we must treat separately and pay an attention to its development.2. According to the study of Case2, Jiangsu spent about 1.2million yuan to control Solidago canadensis L in 2006, and its area is about 8000 ha. now, and have limited its development. This case indicates it's the most optimum that the government controls the alien invasive species before its zoom, and it enhance the use of the finance capital.According to the above analysis and conclusions, the suggestion of preventing and controlling biological invasion in Jiangsu even the whole country are drawn out.This research analyzes the cases from the economic and ecological point of view, and offers a new scientific evaluation method. This method also could be used in the economic and ecological evaluation of the other species.