Occurrence and damage of invasive alien plants in Dehong Prefecture, western of Yunnan Province

Alien invasive plants are a serious threat to natural and agricultural systems, especially in areas with sensitive habitats and high value crops. Dehong Prefecture, western Yunnan Province, China is vulnerable to invasive plants and its current status of invasive alien plants is assessed in this article. We compiled a comprehensive list of invasive alien plants with background information from 2013 to 2015, including origin, life form, habit, distribution, affected crop, and damage. The 90 invasive alien plant species in Dehong Prefecture are represented by 28 families and 66 genera, with the three largest families, Asteraceae, Poaceae and Fabaceae, accounting for 48.9% of all species. The proportion of invasive alien plants originating from the Americas, Europe, Asia, and Africa were 68%, 11%, 10%, and 9%, respectively. Almost all invasive alien plants were found in five cities or counties in Dehong Prefecture, and there were more invasive plant species in Ruili City, Luxi City, Yijiang County, and Longchuan County than Lianghe County. Most invasive alien plants were herbs (84.4%), with annual and perennial plants forming equal proportions (both comprised 43.3%). There were 44 invasive plant species rated as causing minor damage, destructive I grade (49% of all species), followed by 27 species rated at intermediate II grade (30%) and 19 species at heavy damage III grade (21%). Most invasive alien plants were both agricultural and environmental species thus negatively impacting both crop production and ecosystems, often significantly. The major infested crops were vegetables, sugarcane, maize, and orchard crops. Given the large number of alien plant invaders, it was concluded that Dehong Prefecture has become a major “window” for foreign alien plants entering in Yunnan Province and even for China as a whole. More attention should be paid to this issue, and effective measures should be developed to manage the expansion and damage caused by invasive alien plants.