| This paper focuses on the "PSESP" Magnolia sinensis of natural distribution in the DaChuan town in LuShan.Baesd on the field investigation, setted 21 sample area within 7 elevation gradient. Magnolia sinensis population and community characteristics were studied systematically and comprehensively by using quantitative ecology methods.The aims of this study were to provided the scientific basis for construction of recovery, the protection of wild resources and expanding populations, including community characteristics, ecological niche of population, population structure, and interspecific ande intraspecific competition, et al. The results were as follows:(1) Magnolia sinensis communities in the study area in the DaChuan town had a total of 245 vascular plants species, belonging to 64 families and 64 genera.34 families, 126 species of woody plants accounted for 51.4%, the herb 33 families and 119 species accounted for 48.6%. Forest composition is given priority to shrubs and herbs, community stratification is not obvious. The community richness:shrub layer> herb layer> tree layer, seven altitude gradient within the community Shannon Wiener index, Simpson index and pielou evenness index had almost the same change trend; Woody plants had low the Shannon-Wiener index?Simpson index and pielou index, Simpson index:herb layer> shrub layer> tree layer.(2) Magnolia sinensis community diversity showed fluctuation along with the change of elevation gradient, but no significant difference change as a whole. Community diversity in herb layer at an altitude of 2400 m above had significant differenceonly with low altitude. As the altitude risen, the similarity coefficient of species was reduced, commom species were reduced; The similarity between adjacent altitude coefficient is higher. Community's change trend of diversity index were leveled off and the similarity coefficient of species were higher at an altitude gradient of 2100 m above.(3) Fargesia adpressa, Rubus setchuenensis,and Corylopsis sinensis were main associated floristics of Magnolia sinensis. Magnolia sinensis had strong ecological adaptability and wide distribution range, which had higher niche overlap, many species of niche overlap of Magnolia sinensis communities in the Da chuan town could coexist, formed the relatively stable state.(4) The individual population of Magnolia sinensis of diameter class II and III of sapling were account for 89.85% of the sample area within the existing individual number. Population age structure of Magnolia sinensis was characterized by the number of saplings and young trees in the majority. From the point of dynamic evolution trend, Magnolia sinensis population was obviously at the growth stage, the population was relatively stable during a long period of time with great potential updates. Magnolia sinensis along the valleys was presentd distribution cluster, but not high the concentration degree concentrated into strip scattered distribution. It's population distribution pattern was changed along with the change of altitude, distribution pattern was random distribution at altitudes gradient of 1900 m,2000 m and 2400 m above.(5) Results showed that Magnolia sinensis of the sample area, intraspecific competition strength was lower than the interspecific competition strength, Magnolia sinensis intraspecific competition outweigh the various species of interspecific competition strength. Diameter class by the intensity of competition showed a trend of decrease along with the growth of diameter class. Intraspecific competition had experienced two competitive strength of the larger stage, at 2-5 cm diameter and 10-15 cm diameter respectively. |
PDF Full Text Request