Alien harmful species often generate great threats to ecosystem structure, function, biodiversity, as well as social and economic development. In order to occupy a region, alien species rely on multiple dispersal strategies to spread their seed. At present, however, characteristics of dispersal strategies and relationships between the dispersal strategies of alien species and social factors are not clear. 

A recent study was conducted by ZHOU Quanlai and his colleagues from the Institute of Applied Ecology of the Chinese Academy of Sciences. 

"Our aims were to know the characteristics of dispersal strategies facilitating habitat invasion and space expansion across climatic gradients, the main climatic and social factors affecting different dispersal strategies, and correlation between different dispersal strategies of the alien species," said Dr. ZHOU, the first author of the study. 

Dr. ZHOU and his team obtained morphological traits, dispersal modes, and dispersal vectors of 562 alien species by synthesizing the data of Chinese alien species to determine relationships between climatic and social gradients and dispersal strategies. 

They found that dispersed by human, animals, and wind was nearly 90.0% of all the dispersal strategies of the alien species. Mean frost days, mean annual humidity, and gross domestic product were the main climatic and social factors that were correlated to different dispersal strategies. There existed positive or negative correlation between different dispersal strategies. Positive correlation between different strategies might be co-owned while negative correlation between different strategies might not be co-owned by one alien species.  

"Understanding the characteristics of the dispersal strategies of alien species is important for policy makers when controlling the dispersal of malignant invasive alien species, predicting the distribution, and decreasing or cutting off the dispersal pathways of invasive alien species," said Dr. ZHOU. 

This work entitled "Effect of climatic and social factors on dispersal strategies of alien species across China" has been published in a paper in Science of the Total Environment. It was supported by the National Key R&D Program of China and the National Natural Science Foundation of China.