Study On Geographic Distribution And Conservation Ecology Of The Relict Plant Pseudolarix Amabilis

Pseudolarix amabilis is an ancient species which endemic to China.Due to climate change,degradation of habitat quality,and insufficient regeneration capacity,the threaten levels of Pseudolarix amabilis is raised.the current distribution range,population status and regeneration dynamics of it remian unclear,it is difficult to accurately assess its threatened level,this means a great challenge in its conservation.In this study the distribution range of the wild population of was first determined,and combined with the fossil evidence,and the variation of the geographical distribution in different geological periods was analyzed;then,the climate niche model was used to simulate the potential suitable distribution area under the current climate conditions and future climate.And systematically investigated the characteristics,population structure and regeneration status of Pseudolarix amabilis population in 26 plots,revealing the regeneration and maintenance mechanism of Pseudolarix amabilis population.Finally,all the results of this study were combined to reassess the threatened levels of Pseudolarix amabilis.the following conclusions are drawn:1)Due to the drastic climate change,the distribution range of Pseudolarix amabilis had gradually contracted to low latitudes along with geological time.We find five regions harboring wild populations,including: Mao Mao Village in Ningbo of Zhejiang Province,Tianmu Mountain National Nature Reserve in Linan of Zhejiang Province,Linjiatang in Gaohong Town of Zhejiang Province,Huangtanzhuang in Yixian County of Anhui Province,and Qingtangpu in Anhua of Hunan Province,with an altitude of 330-1100 m.Population are severely separated and dispersed.The minimum distance between the groups more than 20 km and the maximum distance up to 800 km.2)The simulation results of the climate niche model show that under the climate conditions of current or future,the potential distribution area(distribution rate ? 0.5)based on the cultivated population is larger than that of the wild population simulation.Under the climatic conditions of 2070,the area of potential distribution areas for both cultivated and wild population simulations will shrink.3)According to the habitat characteristics of the Pseudolarix amabilis population,26 plots were divided into 4 habitat types,including: Natural forest,Secondary bamboo forest and Secondary forest on abandoned agricultural land,Fengshui forest.the species diversity and abundance in different habitats are significantly different.The species diversity and abundance of the secondary bamboo forest are the lowest.4)The regeneration of Pseudolarix amabilis population is closely related to habitat disturbance.Under low-frequency and low-intensity disturbance in natural forest,the population of Pseudolarix amabilis is dominated by old individuals,and the seedlings are insufficiently survived.Secondary forest in abandoned agricultural lands with a continuous population structure,and the young trees are dominant which under the highintensity and low-frequency interference;High-frequency and high-intensity interference in secondary bamboo forest will cause the transform from seedling to sapling be blocked,the population will continue to decline.The population structure of Pseudolarix amabilis population with appropriate management on disturbance frequency and intensity in fengshui forest show a "L-shaped",with good regeneration statution and complete life history.5)The existing threaten level of it had assessed should be upgraded from Vulnerable to Endangered by IUCN.