Predicting The Impacts Of Climate Change On The Potential Distribution Of Endemic Viburnum In China By MaxEnt Model

China has the richest resources of Viburnum(Dipsacales,Adoxaceae)in Asia,making it as Asian center of distribution.Viburnum is highly adaptable to the environment and has great application prospect in ornamental,medicinal,edible,ecological,and flavoring.Endemic Viburnum is a representative group of plants of Viburnum,its distribution change trend,migration trend and flora development process can be predicted by the biogeographic distribution patterns and habitat characteristics.This is of great significance for the introduction,domestication,conservation and rational planning of species diversity protection sites of this genus.The Max Ent model is an important model for studying the impact of climate change on species distribution and migration trend,which can simulate and predict the distribution area of target species scientifically and accurately based on species distribution point data and environmental variable data.In this study,we used Max Ent model and Arc GIS software spatial analysis technology to predict the potential distribution area of 61 species of endemic Viburnum(contains sub-species units)in China under climate scenarios of the present,2050,and 2070 years,based on the data of 5708 distribution points in seven groups and 19 climatic factors.We further screened the main climatic factors that affected the distribution of endemic Viburnum in China and analyzed changes of its highly-suitable habitats under different climate scenarios.We obtained the following results.(1)We analyzed the contribution rate of each climatic factor to the model in the prediction,and identified the main climatic factors that affected the distribution of endemic Viburnum.After screening and analyzing,the main climatic factors that affected the distribution of endemic Viburnum are obtained,and they are: Temperature annual range(bio7),Annual precipitation(bio12),Temperature seasonality(bio4),Isothermality(bio3),Precipitation of coldest quarter(bio19),Min temperature of coldest month(bio6),and Precipitation of driest month(bio14).Among these factors,Temperature annual range(bio7)and Annual precipitation(bio12)are the most important climatic factors that affected the distribution of endemic Viburnum.(2)The model verification was usually evaluated by AUC value.The AUC value of predictive models of endemic Viburnum ranged from 0.908 to 0.998,with a minimum AUC value of 0.908,a maximum of 0.998,and an average of 0.971.The predicted AUC values of 52 species of endemic Viburnum(there are 9 kinds of distribution points data less than five,which cannot be used for simulation and prediction)were all more than0.9,showing that the model fitting effect was well and the prediction results was accurate.(3)During the long process from the current climate scenario to 2050 and then to2070,the analysis of the potential distribution areas of 52 species of endemic Viburnum(there are 9 kinds of distribution points data less than five,which cannot be used for simulation and prediction)revealed that a conspicuous reduction in 29 species,a conspicuous augmentation in 8,and no significant changes in 15.(4)We divided the three level categories of potential distribution habitats for endemic Viburnum based on the classification criteria of possibilities in the Fifth Assessment Report of IPCC.These three categories are: non-suitable habitats [0,0.33),low-suitable habitats [0.33,0.66)and highly-suitable habitats [0.66,1],which provide a scientific basis for the change and calculation for the potential suitable habitats of endemic Viburnum.During the changing process from the current climate scenario to 2050 and then to 2070,Among the 52 species of endemic Viburnum(there are 9 kinds of distribution points data less than five,which cannot be used for simulation and prediction)for which the prediction and analysis has been completed,there are 6species with highly-suitable habitats increasing continuously,26 species decreasing continuously,9 species increasing first and then decreasing,and 11 species decreasing first and then increasing.(5)Endemic Viburnum was mainly distributed in an altitude area of 500?2500 m,and was most distributed in the range of 500?1000 m,and with the most species in the southwest,central south,and east China area.Endemic Viburnum was concentrated in100?120° E,20-35° N,mostly in temperate and subtropical regions,mostly are shrubs and small trees,and the main habitats are focus on shrubs,grasses,coniferous and broad-leaved forest areas.Endemic Viburnum had a relatively high diversity in Guizhou,Sichuan,Chongqing,Hubei,Fujian,Zhejiang,Some regions of Yunnan,Guangxi,Guangdong,Hunan,Jiangxi,Anhui and other provinces also have high species diversity,but the distribution is extremely dispersed.Compared with the current climate scenario,the potential distribution pattern of species diversity in endemic Viburnum was not significantly changed and there was no significant migration under the future climate scenario.However,in some areas of Guizhou and Yunnan,the species diversity has a decreasing trend.Therefore,effective conservation of Viburnum plant resources should be carried out in time by establishing on-site protection areas and ex-situ protection sites.Understanding the spatial pattern of endemic Viburnum is of great significance for collection of new species,preservation of germplasm and conservation of diversity in this genus.