The Distribution Patterns And The Major Influencing Factors Of Invasive Alien Species In China

In recent years,human beings continue to transfer species to areas beyond their natural distribution by intentional or unintentional pathways,and some of them have successfully colonized in new areas.Invasive alien species(IAS)refer to those alien species that pose threats to ecosystem,biodiversity,agriculture or human health.C hina is also facing great challenges of biosafety,and faced with the following scientific problems:(1)What are the spatial distribution patterns of IAS and their first detection records?(2)What external factors are related to the formation of spatial distribution patterns?(3)What invasion hypotheses can explain the spatial distribution patterns of invasive alien animals and plants?(4)How to apply the invasion mechanism to the biological invasion prevention and control? In this paper,the distribution patterns of different families of invasive alien plants and the major influencing factors,the origin and distribution pattern of IAS,the first detection records of IAS,the division of biological invasion risk areas and the interaction between invasive alien plants and animals were studied.The main conclusions are as follows:(1)The distribution patterns of different families of invasive alien plants and the major influencing factors: the species composition similarity coefficient of invasive alien plants showed that the provinces with high species composition similarity coefficient were often geographically adjacent provinces,such as Jilin and Heilongjiang,Gansu and Qinghai.The results showed that although the invasive alien plants had strong environmental adaptability,their distribution was still strongly influenced and restricted by environmental factors.There was a strong correlation between different families of invasive alien plants.The species richness of other families was generally high in the regions with high species richness of one family.The prediction results of the same environmental and anthropogenic factors on the species richness of invasive alien plants of Compositae,Leguminosae and Gramineae showed that the standardized regression coefficients of all predictors had the same direction and similar size,showed high spatial distribution congruence of them.(2)The origin and distribution pattern of IAS: the average number of provinces which the invasive alien plants originated from Europe or Asia distributed in was higher.The average number of provinces which the invasive alien animals originated from South America distributed in was higher.The distribution patterns of IAS based on three different invasion indices were different.For environmental factors,the potential evapotranspiration(PET)or actual evapotranspiration(AET)could better predict AIAS and WIAS richness,and area could better predict RIAS richness.For anthropogenic factors,the gross domestic product(GDP)or human population explained more variation in AIAS or WIAS richness,and transport volume or GDP could better explain the variation in RIAS richness.Generally,the environmental and anthropogenic factors showed identical prediction ability.The results of PLS regressions indicated that one set of predictors showed similar effects to the invasive alien plants and animals within a model,and indicated the spatial distribu tion congruence of them.Removing the environmental and anthropogenic factors,to some extent,will weaken the congruence,but the congruence of plants and animals still exists for AIAS and RIAS richness.(3)The first detection records of IAS: the provinces with the largest number of the first detection records of all IAS,and invasive alien animals,plants,and the other taxonomic groups were Taiwan and Guangdong,and the first detection records of all IAS,invasive alien animals and the other taxonomic groups in Xinjiang were also more than those in other western provinces.The unintentional introduction had gradually become the main way of IAS introduction.It was particularly noteworthy that the cumulative growth rate of the first detection records of invasive alien animals had exceeded that of plants.Compared with environmental factors,anthropogenic factors,especially the number of visitors,had a greater correlation with the first detection records of intentional or unintentional species of various taxonomic groups,which further emphasized the important role of human activities in the introduction of IAS.(4)The division of biological invasion risk areas based on Principal Component Analysis(PCA)and Analytic Hiera rchy Process(AHP): for invasive alien plants,the distribution pattern of invasion risk areas basically showed a decreasing trend from south to North and from east to west.The ranking of Jiangsu,Anhui,Zhejiang,Fujian,Guangdong,Taiwan,Sichuan and Yunnan was stable and the invasion risk was the largest.Jilin,Gansu,Heilongjiang,Shaanxi,Xinjiang,Inner Mongolia,Qinghai,Ningxia and Tibet had stable and low plant invasion risk.For invasive alien animals,Shandong,Jiangsu,Fujian,Guangdong and Guangxi ranked stably in the top,and faced the greatest invasion risk.The animal invasion risk ranking of Gansu,Inner Mongolia,Shanxi,Ningxia,Heilongjiang,Jilin,Qinghai and Tibet was stable and low.The middle risk areas of animals and plants were ma inly in the transition zone between high-risk areas and low-risk areas.(5)The interaction between invasive alien plants and animals: Overall,the results of this study supported the IMH hypothesis,and there was a significant promoting effect between inv asive alien animals and plants.In particular,the role of invasive alien animals on invasive alien plants and the interaction between invasive alien animals and plants in terrestrial habitats showed a significant positive interaction relationship.The specific promotion effect was that invasive alien animals could significantly promote the growth and fitness of invasive alien plants.Nevertheless,the promoting effect of invasive alien plants on invasive alien animals was not significant.Therefore,it was speculated that there was a common synergistic invasion between invasive alien animals and plants,especially the one-way promotion of invasive alien animals to invasive alien plants,which might also promote the formation of the spatial distribution congruence pattern of invasive alien animals and plants.In conclusion,this study deepened the understanding of the distribution patterns of IAS and the spatial distribution congruence of invasive alien animals and plants in China,and also verified the Invasional Meltdown Hypothesis(IMH).In addition,the first detection records also clarified the direction for the introduction and management of alien species.The division of biological invasion risk areas was conducive to further formulating regional exclusive prevention and control policies.