Distribution characteristics and influencing factors of invasive herbaceous plants in the coastal zone of Daqing River system

In the context of the construction of Xiong'an New Area, it is very important to ensure the biological safety of Daqing River system. In order to study the distribution of invasive plants in Daqing River system and explore the driving factors affecting the distribution, the vegetation in the river/lake riparian zone of Daqing River system was investigated. The invasive plants in the riparian zone were identified, the invasion grade of each species determined, the correlation between the distribution of species invasion and influencing factors including natural environment and human activities analyzed, and the risk of plant invasion and preventive measures in Xiong'an New Area put forward. The results showed that there were 24 species of invasive plants in Daqing River system, 54.2% of the invasive species were amaranth and compositae, the annual species and unintroduced species accounted for 83.3% and 62.5%, respectively, and 62.5% of the invasive plants originated from American. Six kinds of plants, including Amaranthus retroflexus, Bidens pilosa, Pharbitis purpurea, Eclipta prostrata, Bidens frondosa, Abutilon theophrasti, were widely distributed in the basin. There were three regions in which the number of species and invasiveness of invasive plants were significantly higher than that in other regions, including Fangshan mountain section in the upper reaches of Juma River in the middle reaches of the basin, Bazhou urban section of Mangniu River in the lower reaches of the basin, and the plain and mountain junction area near the 100 m elevation boundary. Human activity was the main factor affecting the degree of plant invasion. The higher the road network density and the proportion of construction land, the more conducive to the distribution and diffusion of invasive plants. The degree of plant invasion in Daqing River system could be controlled currently, but it was necessary to pay attention to the risk of plant invasion, settlement, and diffusion during the construction of Xiong'an New Area and take early precautions.