Prediction Of Population Dynamics And Simulation Of Potentially Suitable Distribution In Endangered Species Acer Griseum

Acer griseum is a deciduous tree species with high ornamental value.It is endangered in China and endemic to China.Early field investigation showed that the natural populations of A.griseum are very rare and fragmented,facing extinction.Currently,the study on A.griseum was mainly concentrated in growth performance of wild population,natural regeneration,seed reproduction,asexual reproduction,SSR primers development,genetic diversity and population genetic structure.In order to understand the reason of this endangered species,make in situ conservation and ex situ conservation of population rejuvenation and introduction area selection and other protection measures and lay the theoretical foundation for domestication and genetic resources conservation of A.griseum,the population dynamics,survival curves,population age structure,dynamic parameters,static life table and survival curve of natural populations of A.griseum were analyzed by population ecology analysis and the MaxEnt model was used to evaluate the potentially habitat,dominant climatic variables,the change of suitable habitat area in the future climate change scenarios and the simulation of glacial refugia and the high variable chloroplast DNA sequences were screened by using sequencing methods.The main result and conclusions are as follows:1.Population numbers and population structureAn investigation was conducted on six natural populations of A.griseum in Central China.The age structure,static life table and survival curve of the populations were analyzed.The results showed that the number of paperbark maple natural populations was small and is seriously threatened.The Huashan population was declining,and the population of Zhangjiajie and Songxian were increasing.The survival curve of population was in line with the characteristics of Deevey-I model.The survival rate of Zhangjiajie population was the highest with the inflection point presenting in the III age-classes and with the survival rate decreasing at higher risk in III and IV age-classes.The survival rate of Songxian population was lower than that of Zhangjiajie population.Mortality of I age-classes was high,the individuals of II and III age-classes showed good growth with decreasing mortality.The survival rate of Huashan population was the lowest with the survival rate decreasing at higher risk in Ⅰ and Ⅱage-classes,the individuals of Ⅲ age-classes grow well.The results of field survey and survival curve showed that big canopy density and strong interspecific competition were the main reason for the decreased survival rate of seedlings of A.griseum,the lack of large diameter(IV and V)trees in A.griseum may be due to human factors.2.Simulation of potentially suitable distribution of A.griseum based on MaxEnt modelSimulation of potentially suitable distribution of A.griseum based on MaxEnt model showed that the suitable distribution was mainly concentrated in the Central China and a few regions of eastern coastal China,around 26.2°~37.5°N and 102.1°~122.7°E,including Gansu province,Shaanxi province,Shanxi province,Henan province,Hunan province,Hubei province,Chongqing municipality,Sichuan province,Guizhou province,Shandong province,Jiangsu province and Anhui province.Temperature(extreme low temperature)dominated the geographical distribution of A.griseum,followed by isothermality(Bio3)and precipitation of warmest quarter(Bio18).Under the future climate change scenarios in 2080,there is little change on the main distribution area(Central China).The appropriate distribution area will increased by 35.5%(30.63×104Km2),and the local population distribution was slightly shrank.It was inferred that the Qinling Mountains,Daba Mountain,Wuling Mountain,south-west of Zhongtiao Mountains and Wudang Mountains are the ice refugia of A.griseum by the simulation of suitable distribution of A.griseum in the period of LIG(120,000~140,000 years ago),LGM(about 21,000 years ago),current(1950~2000),future(2080).3.Differential Analysis of Non-coding Chloroplast DNA Sequences in A.griseumA total of four highly diverse level of sequences psbJ-petA,ndhF-rpl32,trnD-trnT and trnH-psbA were screened.The intraspecific variation(PICs)of the non-coding cpDNA sequences in A.griseum were significantly lower than that of other tree species.Phylogenetic tree analysis showed that 16 populations were divided into two branches and the geographic distance between each branch within the population was close.So it was speculated that the population of two branches might be experienced long-term geographical isolation leading to the deficiency of effective gene flow among populations.