| Camellia sinensis var. assamica (Camellia-Theaceae) in Hainan is an uncultivated plant which exists in natural forests and has a qenetic relationship with domestic tea plant.C. sinensis var. assamica has a strong adaptability to the environment and resistance for adverse natural environment. It is an significant gene bank for cross-breeding and improved varieties of cultivated tea plant. In early 1990, the researches for the distribution of C. sinensis var. assamica in Hainan were reported, bur it has little knowledge about population structure and distribution pattern. So it's necessary to the population structure of C. sinensis var. assamica from the perspective of population ecology based on the full researches for its distribution pattern, in order to provide scientific supports for the protection and development of C. sinensis var. assamica resources in Hainan Island.This thesis, C. sinensis var. assamica population as the research object, centering on Wuzhishan area aims to conduct the research on C. sinensis var. Assamica population structure in Hainan Island, combined with the key wild plant protection survey method and community plot survey method. And statistical method is also used to further study and analyze the spatial distribution characteristics, population structure, life process,distribution pattern, niche and the basic characteristics of C. sinensis var. assamica. The results showed that:(1) The distribution characteristics of C. sinensis var. assamica in Hainan Island are follows: C. sinensis var. assamica are mainly distributed in the central and western mountains of Wuzhishan city, Qiongzhong county, Baisha county and Ledong county in Hainan Island. The distribution of C. sinensis var. assamica was widely distributed in 11 cities and counties, North, Qiongdong and Qiongnan areas are almost no trace; C. sinensis var. Assamica are mainly distributed elevation range of 900-1200m above sea level, the slope range for the sunny and semi-sunny slope area, and small terrain slope was relatively gentle (? 30°) in the forest community. Among them, C. sinensis var. assamica population in Wuzhishan area was the most typical.(2) The results showed that, plant species composition of C. sinensis var. assamica community was rich in Wuzhishan area, and the number of vascular plants in the community was 72 families and 150 genera and 218 species, Ferns 11 families 15 genera 25 species, Gymnosperms 1 families 1 genera 1 species, Angiosperms 63 families 134 genera 192 species. The composition of the community are mainly composed of Lauraceae, Rubiaceae, Euphorbiaceae, Moraceae, Fagaceae, Sapindaceae, Symplocaceae and other families, and the flora of the community are mainly composed of Huaxia floras components are mainly, at the same time with a strong tropical nature of the flora for the nature of the flora.The vertical stratification of the community was obvious, the total canopy density of the sediments was relatively high, the species composition was relatively abundant, the distribution of herbs and ferns was more, the intergene plants are developed and the epiphytic plants are more common. C. sinensis var. assamica was distributed in the shrub grass layer, important values of tree species and shrub species are highest and occupying the dominant position in the community.(3)The Study on the niche breadth and niche overlap of the dominant species in the forest community of C. sinensis var. assamica in Wuzhishan area showed that, in the forest community with C. sinensis var. assamica distribution, L. variabilis, S. laurinum, E.officinalis, S. octophylla and A. elegans niche width was relatively large, C. lenis,D.binectariferum and S. kachinense niche width was relatively small. The niche overlap between species with large niche breadth was usually higher, such as E. officinalis - S.laurinum, Gironniera subaequalis - S. laurinum overlap values are 0.7805 and 0.7693,indicating that the species of adaptability, and more accompanied by growth; the niche overlap between species with smaller niche breadth was usually lower, such as D.binectariferum - S. Kachinense, B. glomerulata - C. Lenis overlap values are 0 and 0.0633,indicating that the species adaptability was weak, and less accompanied by growth. The niche breadth between the species may have smaller, such as Saprosma ternatum - G.subaequalis, L. Variabilis - G. subaequalis overlap values were 0.0488 and 0.0936,indicating that the species of adaptability, but less accompanied by growth. The populations with smaller niche breadth might also have a larger overlap value, such as D.binectariferum - C. lenis, S. kachinense - Musa balbisiana overlap values were 0.8944 and 0.8192, indicating that the species adaptability was weak, but with the growth.Consolidated results showed that, the dominant species of L. variabilis, S. laurinum, E.officinalis, S. octophylla, A. elegans, G. subaequalis and S. ternatu are all occupied certain advantages in C. sinensis var. assamica community. Among them, L. variabilis,S.laurinum and E. officinalis were distributed at the age of C. sinensis var. assamica, and were associated with C. sinensis var. assamica, and there was interspecific competition with species of C. sinensis var. assamica. The C. sinensis var. assamica has the same relationship with the C. sinensis var. assamica Community stability and development.(4)The study on the dynamic characteristics of C. sinensis var. assamica population showed that, the C. sinensis var. assamica population was of stable type in Hainan Island,because the young trees and middle trees are in the majority, and the big trees and old trees are rare; which the population was concentrated in the distribution area, such as Wuzhishan C. sinensis var. assamica population belong to growth type, because the proportion of seedlings and saplings are larger and juvenile individuals were more than adult individuals. The C. sinensis var. assamica population was close to Deevey-I in Hainan Island and the C. sinensis var. assamica population was close to Deevey-II Type in Wuzhishan. The mortality curve showed that the C. sinensis var. assamica population increased with the increase of diamonds in Hainan Island, and the C. sinensis var.assamica population was close to Deevey-III Type in Wuzhishan, combined with life table analysis, C. sinensis var. assamica population survival rate of young plants was high, the population as a whole stable,and showed steady growth in Wuzhishan area.(5) The spatial pattern of C. sinensis var. assamica population was studied by comprehensive pattern aggregate index. The results showed that, the distribution index of C. sinensis var. assamica population was 15.8886>1, t value=72.9476 in Hainan Island; C.sinensis var. Assamica population was 18.5896>1, t value=48.1775 in Wuzhishan. The distribution pattern were clustered of C. sinensis var. assamica population in Wuzhishan and Hainan Island , and the population difference coefficient was significant. But the C.sinensis var. assamica population aggregation intensity was greater, deviated from the random distribution in Hainan Island. |
PDF Full Text Request