The Research On Population Ecology Of Rare And Endangered Plant Taxus Chinensis (Pilger) Rehd.

Taxus chinensis is the first-class plant under protection, and also the rare and endangered plants in China. This paper main used the population ecology theory, and applied the population statistic , statistical ecology methods to analyse the species , population, community quantitative characteristics of the Taxus chinensis. Including the Taxus chinensis population size structure and altitude structure, the life table in a specific time , population survival analysis , spectral analysis of the population dynamics , population growth dynamics of the base area , and niche characteristics of the arborous layer . Finally , explored its endangered mechanism , conservation strategies, for constituting the theory foundation of the Taxus chinensis wildlife resource conservation , acclimatization , artificial breeding and implementation . And also for providing some consult of the research on Plant Population Ecology .Because of the slowly growth speed and long vegetative cycle of the Taxus chinensis, hunting the life track of all individual from the same population is impossible . So the paper applied the space-time replacing method to compile the life table in a specific time , and draw its survivorship curve , finally analysed its population size structure , altitude structure , and life process . The result of the population size structure indicated that , the Taxus chinensis population belongs to stable or growing population , and it can be nicely self-restored in a natural condition ; the result of the altitude structure indicated that, population altitude structure displayed telescoping, the anterior part of the survivorship curve displayed concave , the after part of the survivorship curve displayed liner , and the population trend towards to stable type , when instability ratio equal to 49.38, the population trend towards to growing type ; the result of the life table indicated that, the survivorship curve of Taxus chinensis belongs to the type of Deevey-III, the individual is copiously in seedlings period , but its death ratio is also very high , nearly to 89.6% , and the individual is relative stable in the period of adulthood , in general, the Taxus chinensis population tend to stable growing type ; the result of the death climax analysis indicated that, the change of death ratio curve accordance to killing power curve , all displayed the corrugated form , the death climax appeared in the crest of wave of the two curve , and there are four death climax in the whole life process , in general , the population was developed in a relatively balanced condition ; The result of the population dynamic spectrum analysis showed that, the Taxus chinensis population was exists periodically characteristics , moreover displays the undulation is not the sole cycle, at the same time, the small cyclical undulation in a big way, also has the characteristic of small cyclical in the great cycle the multi- overtones iteration, this kind of characteristic and the forest divide the renewal and the jamming related, favors the Taxus chinensis self- stable maintenance . By studying the increasing tendency of Taxus chinensis population, we can find that the Taxus chinensis population will get a fastest velocity of increasing when its base area is 2.520 m~2 /hm~2, and the fastest increasing velocity is 0.91728m~2/age class year, the corresponding period is third age class phase. In other words, DBH arranges from 8.0 to 10.0 cm.Regarding the Taxus chinensis population sampling spot as the situating of one dimension resources, using of the method of quantifying niche, the writer measured the species of arbor in Taxus chinensis population from the tow aspects: the width of niche and the overlap of niche. Concluded that: generally speaking, the niche of different dominant trees is obviously different, and the distribution of every kind of trees in the population is asymmetry; Taxus chinensis adapts to the researched area better. We can concluded this from the fact that Taxus chinensis and China Pinus Armandi have a widespread distribution, a great number, a great biomass, a full using of the surrounding nutrients; Taxus chinensis population is a consociation mainly made up of Taxus chinensis; the value of niche overlapping is less than 0.03, occupies 66.07%, shows that the other tree species share little nutrient with Taxus chinensis, but Taxus chinensis overlaps well in different resource state, so they can share the resource better and complement each other.From the generalization of the conclusion before , and the endangered mechanism of the Taxus chinensis, found the reason which lead to the Taxus chinensis in the endangered condition is , restricted by its biological characteristics , high death rate of the young seedling , strict habitat selection , and negative interference and influences by human being. Meantime, provided some protect policy direct towards the root of the endangered mechanism.