Ecological Study Of Platnthera Chlorantha Population In Lingkong Mountain

Using "sample-plot"method to investigate Platanthera chlorantha population under different site conditions,in P.chlorantha important distribution area in Shanxi-Shanxi Lingkong Mountain National Nature Reserve.18 plots were set up, select 42 plots containing P.chlorantha. Population statistics,species diversity indexes,Pearson correlation analysis, and Spearman rank correlation analysis,niche analysis and other scientific method to study the habitat characteristics, population characteristics and community ecology of P.chlorantha and preliminary analysis the threats to the species,and then puts forward protection countermeasures. The study fills the blankness of P.chlorantha population and provides strategic decision in protection of the population.After our research and analysis, the following main conclusions were got:1. Population density and height structured of P.chlorantha:Population density difference is obvious in 18 plots. The plot A4 has maximum population density. The plot An has minimum. Due to the different habitats, distribution of P.chlorantha also exists obvious difference. The survey found that P.chlorantha density heterogeneity is the result of its opposition response to ecological factors. Among them, the light conditions and soil humus may be the key to constraint population growth and distribution. Analysising P.chlorantha population density of every plots can be learned that the growth of this species need not only the scattering sunlight enough,also certain shade conditions, which are both indispensable. P.chlorantha species’height under 10cm has the most largest population,accounting for 68.97% of the total,as the main part of P.chlorantha populations. The height class structure are basicly "Pyramid".2. Diversity characteristics:P.chlorantha associated community herbaceous plant has a total of 21 species, belonging to 15 families and 21 genera, which families and genera compositionis are more dispersed and species are mainly focusen on single species families and single species.From the view of floristic elements, the temperate distribution is the largest, accounting for 42.86% of the total species, which embody typical temperate nature of Lingkong mountain herbaceous flora;secondly,China endemic species, accounting for 28.57% of the total species, which is obvious that personality characteristics of Lingkong mountain vegetation flora.From the important value of each species in the community, the important value of P.chlorantha is accounted for 55.58% among all populations, which is the dominant species in the herbaceous community. The study on community diversity shows tendency of 18 kind of diversity index showed aconsistent, Shannon-Wiener index and evenness index E and population density was negatively correlated, Simpson index and population density was highly significant positive correlation, it was significantly negatively correlated with other index.The values of Shannon-Wiener index were between 0.66 to 1.30.Those of Simpson were 0.17 to 0.61.And those of evenness index were 0.60 to 0.92. All above said that the diversity of the were low.3. Interspecific association:The result show that the relationship between P.chlorantha with Carex lanceolata and Phlomis umbrosa are obviously significant negative association. However, the population size, the distribution area and dominance of these species in Pinus tabuliformis forest are very clear.The result instructions that P.chlorantha showed a strong ecological adaptability in herb communities under P.tabuliformis forest. According to the relationship of species association, the 15 dominant species were be divided into 3 ecological species groups.P.chlorantha was divided into a single ecological species group,because of its biological characteristics and environmental harshness.4. Niche characteristics:the results show that The niche breadth index of P.chlorantha is maximum and Peucedanum Harry-smithii is minimum. The niche overlap values indicate that, species pairs have niche overlap a total of 162, accounting for the total log 72%. From the niche overlap distribution pattern of view, the dominant plant Ljh and overlap values overlap with the Lhi value proportional is difference, indicating that the tendency to share the various groups of resources is obvious and it is a relatively stable community.Currently, P.chlorantha face a potential threat from human disturbance,especially grazing activities,which seriously affects P.chlorantha growth.Therefore, it should be to eradicate livestock backyard and reduce human activities as the main way to reduce the destruction and growth disturbance from livestock and people in protected areas.