A Study on Environment Ecology of Endangered Plant Calophaca Sinica at Tianlong Mountain
|Keywords||Calophaca sinica population age structure distribution pattern inter- and intraspecific competition|
This article concentrated on research of Chinese rare and endangered plant Calophaca sinica in Tianlong Mountain provincial nature reserve in Taiyuan city Shanxi province aiming at providing the protection and artificial cultivation of Calophaca sinica a scientific basis through age structure, distribution pattern, interspecific and intraspecific competition and soil element character. The main results were as follows:The Calophaca sinica population had been signed with decline trend by having a spindle-shaped age structure in which only 32.9% of Calophaca sinica was seedlings and young trees. During the height investigation, that 83.7% of Calophaca sinica’s heights were less than 2 meter, comparing to a normal plant height between 2 meter and 2.5 meter, proved a high competition pressure within population. Distribution pattern consequence showed that most of Calophaca sinica population clumped and all of seedlings and young trees presented clumped distribution which contributed to increased competition pressure and hence to population decline.Niche width research showed greatest value of Calophaca sinica within eight species which was 17.423, quantatively far higher than other species. Consequence of niche overlap between Calophaca sinica and other seven species witnessed the following order: Myripnois dioica> Rosa xanthina> Pinus bungeana> Platycladus orientalis> Vitex negundo> S. microphylla> S. trilobata. This result gave birth to most evident competitors including Pinus bungeana, Platycladus orientalis, Myripois dioica and Rosa xanthina. Inter-specific and intra-specific competition of Calophaca sinica population illustrated that inter-specific competition intensity decreased with the increase of Calophaca sinica age and intra-specific competition intensity was proportional to its age. The effect of inter-and intra-specific competition was in accord with the result of age structure research which showed the scarcity of young stage trees and senescent individuals respectively.12 soil elements content analysis in Calophaca sinica habitat showed that young trees of Calophaca sinica were inhibited most severe in winding mountain highway area where the contents of three heavy metal elements Cd, Cr, Pb were 0.28,10.00 and 2.08 respectively which differed a lot from other three areas. Cluster analysis outcome was affected mostly by soil contents of Ni and Ca, whose F value was 43.130 and 34.800 in ANOVA analysis. Hence these two elements influenced growth of Calophaca sinica remarkably. Through principal component analysis (PCA) we concluded that plant growth index, plant stress resistance index and soil pH could be used as substitute for directly determining element contents in order to analyze their demand of Calophaca sinica growth.