Alien Invasive Organisms in Forest, Grassland and Wetland Ecosystems in Anji County of Huzhou City and Their Risk Assessment

As the birthplace of the concept of “lucid waters and lush mountains are invaluable assets”, the problem of alien invasive organisms in Anji County has attracted much attention. Through the field investigation of forest, grassland and wetland ecosystems in Anji County, the species and hazards of alien invasive organisms in this area were comprehensively understood, and the risk level of invasion was evaluated. The results showed that: there were 13 species of alien invasive organisms in Anji County, including Eichhornia crassipes, Ambrosia artemisiifolia, Alternanthera philoxeroides, Amaranthus spinosus, Solidago canadensis, Dysphania ambrosioides, Hydrocotyle sibthorpioides, Ipomoea triloba, Bidens tripartita, Bidens alba var. Radiata, Pomacea canaliculata, Pseudomonas syringae pv.actinidiae and Corythucha ciliate. Among them, there were 4 species of Asteraceae plants, accounting for the largest proportion of 30.8%. From the perspective of geographical distribution, most of these alien invasive organisms were native to the Americas, with the largest number of 6 species in tropical America, accounting for 46%. From the perspective of township distribution, Dipu Town and Baofu Town had the most abundant alien invasive species, with 10 species, accounting for 76.9%, while Xilong Town and Guishan Town had the least, with only 5 species, accounting for 38.5%. According to the distribution of each species, Solidago canadensis, Alternanthera philoxeroides, Amaranthus spinosus and Bidens tripartita were distributed in all townships in the county. Corythucha ciliata was only distributed in Baofu Town, and Pseudomonas syringae pv. Actinidia was only distributed in Tianzihu Town. From the perspective of habitat distribution, the species were mainly distributed in the shelter forest land and shrub land, with 418 and 412 recording points, accounting for 34.4% and 33.9%, respectively. The results of risk level analysis showed that there were 5 alien invasive species with first-class risks and 8 species with second-class risks in Anji County, and the risk of invasion was relatively high. Therefore, it was suggested that the comprehensive control measures should be taken according to the risk level, and the scientific hazard prevention and control of alien biological invasion should be carried out to maintain the stability and ecological security of the ecosystem.