Studies On The Spatial Pattern And Surviving Process Of Changium Smyrnioides Wolff, An Endangered Plant

Rareness is the auspice of species extinction. Except for we find out the essential matter of rareness, the reason of extinction will be the puzzle. If human want to carry out one efficient plan for protecting the species and making use of the natural resource sustainedly, the matter and mechanism of extinction must to be illuminated, and meanwhile it spur people up to study the phenomenon of rareness and endangered species. Among the most study methods, spatial population ecology and number population ecology is the main technique in discussing the endangered mechanism.We put up the study of spatial pattern ofChangium smyrnioides Wolff., an endangered plant species using the theory of characteristic differentiation in evolutionary process, paralleled with discussing the distribution pattern of another species Anthriscus sylvestris (L.) Hoffm. belongs to the same family Umbellaceae investigated in different habitats in Hangzhou by using grid sampling. Also we analyze the dynamic of population based on the confirmability of the important age parameter by using the nondestructive method. After all, the main endangered mechanism and reference of protection of this species is offered. The study results are showed as following.(1) We use the Logistic growth model to estimate the age of the individuals with the exterior quantity characters, and conclude the upper limit of age is 50a. 8.8255g is the turning point of root biomass increase in theory. We obtain the decay type structure of population from the imitating the theoretical distribution by Weibull function.(2) As for C. smyrnioides, the distributions pattern of individuals is mainly influenced by the biological characteristics itself in small classes, but the light in great classes. A. sylvestris respond to both water and light in its spatial pattern, but mostly, water limits the distribution bound, and the powerful competition capacity decides the distribution in miniature.Individuals of C. smyrnioides are not easy in getting together and the stems with flowers appear uniform pattern in favor of the distribution of seeds and open up the developing space in small classes as 0.02m2~0.04m2 with some degree in changing the type of distribution pattern. Meanwhile the phenomenon of aggregated pattern is accordant in great classes. Middle-aged individuals appear the greatest intensity in 1.28m2 and2.56m2. The ramets of A. sylvestris are aggregated pattern in all classes and habitat type distinctly, but mother plants are similar to the C. smyrnioides. It implies that the A. sylvestris population will be in self-thinning period at end of development period. Procreation characteristics decide the difference spatial pattern between those two species in small classes and the degree of aggregation of C. smyrnioides is less than A. sylvestris.We consider that the individuals with one seed bourgeoning and becoming one mature individual has contributed for the whole population. And the population has been on speaking terms with the geographical environment successfully in evolutionary process but somewhat it can not keep up with the process of changing micro-climate and disturbing behavior made by human in its habitat patches. C. smyrnioides has only basal leaf that is the main apparatus in photosynthesis, so it needs enough light under the seasonal gap to make preparation for the maturity of seed in later of procreation period, and accordingly, the individual numbers under the shade of defoliated tree is less than the habitats of gap. It is one important way for C. smyrnioides to occupy the living space, which the seeds transmit through the rainwater under the crown.(3) Based on the static life table and fecundity schedule both depending on the experimental data of seed-seedling conversion rate and seedling survival rate, the killing power (K), Deevey curve and Leslie matrix model are applied to analyzing the numerical dynamics of the population. All data are obtained from the field investigation such as age structure, seed production and natural germination rate...