| At the macro-scale,climate is the main factor that determines the type of vegetation and species distribution.More and more attention has been paid to the research on predicting the impact of climate on species distribution and the relationship between them.Studies on global warming have shown that the arid and semi-arid regions have seen the most significant warming in the last 100 years.Moreover,the arid and semi-arid areas have been affected by desertification for a long time,and the fragile ecological environment problems in this area have become increasingly prominent.Anabasis aphylla is the main species and dominant species of desert vegetation,it has high capabilities to endure salt-alkali and resist drought,and plays an important role in maintaining the balance of desert ecosystems.In order to find out the potential distribution range and spatial distribution changes of A.aphylla in northwest China under the current and future climate scenarios,and to analyze the main environmental factors that limit the distribution of A.aphylla,this paper uses field investigation,China digital herbarium,global biodiversity database,published paper and Chinese flora,etc.,to obtain the distribution data of A.aphylla.Then de-duplicate and screen the obtained distribution points.In this study,20 environmental variables were selected,and the potential distribution range and changes of A.aphylla in current and future climate scenarios were predicted based on MAXENT and ArcGIS software.The contribution rate of each environmental variable and its niche parameters were analyzed,and the relationship between geographical distribution and environmental factors and the reasons for the current geographical distribution pattern were further explored.At the same time,in order to further study the level of genetic diversity of the A.aphylla population,so as to provide a basis for its biodiversity protection.This experiment took Xinjiang as the study area.A total of 106 samples were collected from the population of A.aphylla distributed in seven sites: Bole,Atush,Changji,Karamay,Kuqa,Hutubi and Shihezi.SLAF-seq simplified genomic technology was used for sequencing to analyze the genetic diversity of A.aphylla populations,the main results were as follows:(1)MAXENT model predicts the potential distribution of A.aphylla in northwest China showed: the highly and very highly suitable distribution areas of A.aphylla were mainly concentrated in the southern margin of the Junggar Basin and the western side of Tarim Basin.In addition,A.aphylla also had a suitable distribution in some areas of the Hexi Corridor.The suitable distribution value of A.aphylla in Inner Mongolia and Qinghai was low.A.aphylla were mainly distributed in northern xinjiang,and a small amount in southern Xinjiang.(2)By calculating the area of A.aphylla distribution area under different suitable levels,compared to the past climate scenarios,the area of the unsuitable distribution respectivelyincreased by 2.6%,2.35% and 2.59% under the current,2050 and 2070 future climate scenarios,while the distribution of the sum of the extremely high and high suitable distribution areas decreased by 6.16%,11.56%,and 7.65% respectively.(3)The analysis of the environmental factors that affect the potential distribution of A.aphylla showed that: In the current climate scenario,the seasonality contributed the most,with 31%,followed by the precipitation in the wettest month(18.1%),the annual average precipitation(10%)and the lowest temperature in the coldest month(9.2%).According to the corresponding curve,when the precipitation seasonality exceeds 80%,the fitness probability of A.aphylla significantly decreased.The optimum range of annual average precipitation of A.aphylla was about 140 mm,too high or too low precipitation was not conducive to the growth of A.aphylla.(4)Using SLAF-Seq simplified genomic technology,a total of 1627177 SLAF tags were developed in this study.According to the selection requirements of MAF?0.05 and integrity?0.5,a total of 300105 highly consistent and confident SNP markers could be used for subsequent genetic correlation analysis.(5)Through PCA analysis,the result showed that the first principal component and the second principal component divided 106 samples of A.aphylla into two groups.KC and ATS groups form a cluster,and BL,CJ,HTB,KLMY and YSJ regions of A.aphylla were clustered together.This is consistent with the clustering results of the phylogenetic tree.(6)The calculation results of the genetic diversity index of A.aphylla population showed: The average Shanon_Wiener index and Nei diversity index of A.aphylla population were 0.4440 and 0.2854,respectively.By calculating the genetic distance between the populations of A.aphylla,the results showed that the genetic distance between Changji and Shihezi 149 group was the smallest,which is 0.000806.The genetic distance between YSJ and ATS was the largest,which is 0.997326.The results of AMOVA analysis showed that72.36% of the genetic variation in the A.aphylla population was mainly from populations,it shows that most of the genetic variation comes from regions,and the genetic differentiation among populations is relatively small. |
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