Composition characteristics of alien species and distribution ofinvasive alien species in Beijing

With the economic development, the number of alien species, especially invasive alien species, is increasing quickly, which might affect the stability and sustainable development of local society, economy and natural ecosystem. According to extensive field investigations in Beijing and literature consultation, 234 alien species which belong to 165 genera and 72 families were recorded including original distribution area, flora, the usage of plants and invasive alien species in Beijing. The results show that 67.77% of alien species were introduced from other Asian countries. The world distribution plants account for 38.03% and ornamental plants 28.22% of the total alien species. Composite, Leguminosae and Rosaceae families have more species than other families. Twenty-eight invasive alien species were recorded in the field investigation, and their risk and history of distribution were analyzed. The number ofinvasive alien species is the most in Tongzhou District, 18 species, but the least in Haidian District, 1 species. We finally propose countermeasures for management of alien species, prevention ofinvasive alien species and protection of biodiversity in Beijing.