Abstract: West Jilin Province is a typical area of the ecotone between agriculture and animal husbandry with frangible eco-environment. From the aspects of water resources, natural disasters and land degradation, 10 indices were selected to establish matter-element model for the assess-ment of eco-environmental frangibility in West Jilin Province. The results indicated that in 1985—2000, Qianan, Fuyu and Changling Counties had the least frangibility (level Ⅰ), Daan and Qianguo were in the second place (level Ⅱ), and Taobei, Zhenlai, Taonan, and Tongyu had the highest frangibility (level Ⅲ). As a whole, the counties in Songyuan City were less frangible than those in Baicheng City. Different counties had different sensibility to the environmental factors, e . g ., Daan and Tongyu were most frangible in water resources condition, and Taobei, Zhenlai, Taonan, Tongyu and Qianan suffered most from natural disasters, while Taobei, Taonan, Qianguo were threatened by severe land degradation.

Key words: Tobacco variety, Predatory arthropod community, Structure and dynamics