| Summary: | 博士 === 國立屏東科技大學 === 生物資源研究所 === 102 === The rare and endangered plant can only survive in the unique environment and it’s limited habitat. It is easy to be threatened by the climate change and habitat loss. In Tertiary and Quaternary, the genus of Amentotaxus experienced population expansion and contraction over periodical glaciations. In the present age, these descendants of Amentotaxus genus were distributed within restricted regions of southern China, Taiwan and Vietnam. Amentotaxus formosana Li is a rare and endemic species in Southern Taiwan. It is an endangered species in the world and protected by the Cultural Heritage Preservation Law in Taiwan. Recently the microsatellite molecular fingerprint is an and effective technology to analyse the population genetic structure of species. To evaluate the status of the forest health, using VTA method and analysising indices of tree health assessment are effective and scientific methods to monitor the forest health. In this study, I sampled and experimented in habitats of Amentotaxus formosana, the Chachayalaishan Major Wildlife Habitat, Dawu Taiwan Amentotaxus Nature Reserve(Dawu), and Mt. Dalili. We used VTA method to select the seven trees indicators and extracted five factors to monitor the forest health of A. formosana. The results indicated that the canopy density index is the best, the second index is the vitality of the canopy, the third index is the status of root, the fourth is the tree competition and the fifth is the leaves falling index. About the health grade distribution in Chachayalaishan, the degree of "healthy" has the highest proportion of 49.20%, while the deterioration status accounted for more than half the proportion (50.80%). The same situation in Dawu , the degree of "healthy" has the highest proportion of 48.71%, while the deterioration status accounted for more than half the proportion (51.29%). In ecosystem scale, I used chi-square test to discuss the influence of altitude, slope, aspect and whole light sky space in the health of Amentotaxus formosana Li, and it showed no significant correlation between them. There are 5 vegetation types also in study area, including Dysoxylum hongkongense-Schefflera octophylla type, Castanopsis cuspidate-Schefflera octophylla type,Cryptocarya chinensis-Schefflera octophylla type, Prunus phaeosticta-Machilus japonica type, Lithocarpus dodoniifolius-Machilus thunbergii type. and Euonymus tashiroi-Machilus thunbergii type, Machilus kusanoi- Litsea acutivena type and Drypetes hieranensis-Castanopsis cuspidate type. Further the tree size distribution of the A. Formosana displayed the inverse J-shape type distribution. In this study, I used the microsatellites DNA fingerprinting to evaluate genetic diversity of A. formosana. We found all populations significantly deviated from Hardy- Weinberg equilibrium. In addition, we used the AMOVA to analysis the population structure . There were a great quantity of genetic variations within population and there may be the potential subpopulations. The STRUCTURE and GENELAND were also used to analysis the population structure and found that the whole population were divided into two groups genotype nine groups genotype (K = 9). In this research, I established the genetic, species and ecosystem levels research model of A. formosana to assist the future reference to ex situ conservation or in situ conservation. Future we will look forward to establish long-term A. Formosana ecological database. These information will be helpful for conservation of the rare and endangered plants.
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