The Prediction Of The Bamboo Leaf Chai Hu Shisheng Area And The Impact Of Climate Change On Its Spatial Pattern

Global warming has become the main trend of today's climate change,which gradually increases the potential risks of mankind and ecosystems.Predicting potential geographic distribution of the species is important from species and habitat restoration point of view.Therefore,taking Bupleurum marginatum which is the main medicinal material in the Chinese herbal medicine market for research objects,134 species occurrence points and 16 environmental variables are used to predict the potential distribution of B.marginatum by using MaxEnt model and ArcGIS spatial analysis technology in this paper,meanwhile,the dominant environmental factors affecting their distribution are quantified.Then using three kinds of climate models(BC,HE,MC)and three representative concentration pathways(Rcp2.6,Rcp4.5,Rcp8.5)to predict the pattern transformation characteristics of B.marginatum,explore the migration orbit of high habitat suitability class,identify the ecologically sensitive area and ecologically critical area of B.marginatum during the future time periods 2041-2060(2050s)and 2061-2080(2070s).The results can provide data support and reasonable suggestion for the precise positioning,rational planning and scientific planting of the late stage of B.marginatum.The main conclusions are as follows:(1)The simulation results of the potential distribution of B.marginatum in the current context show that only 12.99%of the area comes under high habitat suitability class which is annularly distributed in the southern provinces of the junction,mainly in Henan Province,the northwest of Hubei,southern Shaanxi,Longnan City,the northwest of Sichuan,central Yunnan,the north of Guangdong and Guangxi,and the west of Jiangxi;The moderately suitable class accounts for the total area of 18.89%,mainly distributed in the surrounding high suitable areas;30.97%in low suitable class while major percentage(37.15%)of the study area shows the least potential.(2)The relative importance of the environmental variables is assessed by Jackknife tests in the modeling analysis.And the results show that among the 16 environmental variables,mean temperature of the coldest quarter(Bioll)is the most significant contributor to the habitat suitability distribution of B.marginatum followed by annual precipitation(Bio 12),temperature annual range(Bio7),precipitation of growth period(PG),mean diurnal temperature range(Bio2),precipitation of the coldest quarter(Bio 19)and isothermality(Bio3).Thresholds of dominant factors of B.marginatum:Bioll ranges from-1 ? to 14 ?,Bio 12 ranges from 800 mm to 1500 mm,Bio7 ranges from 26 ? to 33 ?,PG is 100 mm,Bio2 is 17 ?,Bio19 is 15 mm,Bio3 is higher than 4.8 ?.(3)There are some systematic errors in the results of model prediction,however,model patterns all reflect that climate changing is beneficial to the expansion of potential distribution area of B.marginatum.To 2070s,high habitat suitability class of B.marginatum significantly expands in the climate change scenarios,accounting for 22.58%of the total area of the study area.The moderately suitable class also increases,accounting for 28.28%.The low suitable class accounts for 32.97%which has a smaller fluctuations over time,and the least potential is 16.17%.(4)B.marginatum's migration orbit are all different in three atmospheric circulation model under three representative concentration pathways.In addition to BC model Rcp2.6 and Rcp4.5 as well as MC model Rcp2.6,the rest of the climate models under three representative concentration pathways don't predicte the trend of migration to high latitudes,most(5/9)scenarios show westward migration of centroid.(5)Climate change prediction shows that the ecologically sensitive area and ecologically critical area of B.marginatum are amplified with the passage of time.To 2070s,the ecologically sensitive area of B.marginatum increases and the degree of landscape fragmentation aggravates,the two provinces of Sichuan and Yunnan in the Southwest China are the harder-hit areas,which need to be protected and restored as soon as possible;Qinba Mountains,Hengduan Mountains,Yunnan Plateau and Nanling Mountains are the ecologically critical area of B.marginatum.Thus,these four regions can be identified as the priority protection areas of B.marginatum in the future.