Age Structure and Gene flows of Fine-scale Populations of Oreocharis dasyantha（Gesneriaceae）,an Alpine Herb Endemic to Hainan Island

Key words: 
• Oreocharis dasyantha /
• patch /
• isolation /
• population dynamics /
• conservation /
• Hainan Island /

Abstract: The spatial distribution,age structure and individual migration of plant populations in a partial landform might give a deep revelation of dynamics and potential adaptivity of plant populations,which is a good reference for formulation of effective conservation measures for the plant populations.Four geographic populations of Oreocharis dasyantha,an epiphytic herb endemic to mountains in Hainan Island,which grow on rocks and are distinctly different in population at four sites,were selected to study their age structure and life table for each patch（fine-scale local population） within each geographic population,and to analyze the genetic structure and the intensity of gene flow between the patch populations by using the nuclear gene ITS and two chloroplast genes（trn L-F,ycf1b）.The results show that the O.dasyantha populations tended to expand in the humid area of Hainan Island but tended to decline in the dry area of Hainan Island.The fine-scale local populations of O.dasyantha within the same site differed greatly in age structure,growth rate,mortality and disappearance rate,and were found to have private haplotypes growing in the same site.This may be due to the isolation effect of microtopography,such as the slope valley and the path,which led to the blocking of gene flow of O.dasyantha with weak dispersal ability on the fine scale（about 10 m）.Therefore,for 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 microhabitat such as slope valley and road to ensure long-term field conservation of the wild populations.