Conservation Genetics Of Oreocharis Dasyantha (Gesneriaceae),an Alpine Herb Endemic To Hainan Island

Rich biodiversity,and most of the endangered plants and endemic plants in Hainan Island,is a key area for biodiversity conservation.In this paper,the Hainan Island alpine endemic Oreocharis dasyantha as the research object.Firstly,we study the different geographic populations and fine-scale populations of population age structure and static life table.Secondly,we study the genetic diversity,genetic structure and gene flow among different geographic populations.Finally,we study the genetic structure and gene flow among fine-scale populations.1)The results show that the O.dasyantha populations(WZ and JF population)is expanding in the humid area of Hainan Island.The percentage of individual numbers in the ? age class is as high as 50%,and the percentage of individual numbers in the ? age class is 40%.But other populations is declining,which located in the dry area of Hainan Island.The geographical population of HM,the percentage of individual numbers in the ?age class is 45.82%and the percentage of individual numbers in the ? age class is 19.9%.In the geographical population of NG,the percentage of of individual numbers in the ?age class and ? age class is 25%,which is the highest.The age structure,growth rate,death rate and disappearance rate of groups between different patches are inconsistent within each geographic population.The fine-scale populations located in the south slope is expanding,where is small canopy density,less species of associated plants,more sandy rock or humus,and has a big stone.Howerver,The fine-scale populations located in the east slope is stable or even decreasing,where is large canopy density,associated plants diversity,sandy soil or humus thin and has a small stone.2)We use the nDNA ITS and two cpDNA(trnL?ycf1b)to analysis the genetic relationship between 11 geographic populations.The results show that most of the genetic variation come from the region,and there is no share haplotype among the regions.The geographical populations located on the northwestern side of Changhua River is cluster together,and their genetic relationships is close to those of the south side of Changjiang River,but their genetic relationships between the population and the eastern side of Changhua river is relatively independent.Most of the genetic variation from the region among the three regions,the population genetic structure of the STRUCTURE analysis corresponds to the three regions of the Changhua River isolation.This shows that the Changhua River Valley has a certain isolation effect on the endemic plants of Hainan Island and it hinders the gene flow and population diffusion on both sides of Changjiang River Valley.According to the analysis of the evolutionary tree,the WZ population has a long history of evolution,and the genetic relationship with the external species of Oreocharis auricular and Oreocharis benthamii is relatively close.Therefore,the WZ population may be the most primitive population and spread with the flow of Changhua river.3)The private haplotypes were found in multiple fine-scale populations within each geographic population,of the private haplotypes are directly derived from dominant haplotypes,and a part of the private haplotypes become an independent branch.This may be due to the isolation effect of microtopography,such as the slope valley and the path,which leads to the blocking of gene flow of the O.dasyantha with weaker diffusion ability at the fine-scale(about 10m).The greater the physical isolation intensity,the more impeding the diffusion of gene flow,and the weaker gene flow intensity among the groups.Consequently,in term of herbaceous plants with poor dispersal ability,it is necessary to maintain a smooth corridor for reproduction even at the fine-scale level,so as to avoid adverse effects of microtopography on slope and path and ensure long-term field conservation of the field populations.