Population Dynamics And Community Characteristics Of The Staphylea Holocarpa In The Yunqiu Mountains

Based on the quadrats investigation, the place which is at the elevation of 1000-1580 m of the Yunqiu Mountains was selected as sample. To provide a scientific basis for the conservation and sustainable utilization of the Staphylea holocarpa, the characteristics of the S. holocarpa survival community, including population structure, the flora of plants, classification and ordination, species diversity and interspecific association, was studied systematically by using methods of plant geography,quantitative ecology and population ecology. The results showed:(1)There were 222 species of vascular plants, which belong to158 genera of 62 families, including 1 species of fern, and 61 families 157 genera and 221 species of angiosperms, which include55 families 136 genera and 192 species of dicotyledonous, and 6families 21 genera and 29 species of monocotyledons. Dominant family and single-genera could be observed in the floristic composition.(2) The type of distribution was diverse. There are 13 distribution types and 10 variants. In the analysis of genus, the distribution types follow an order: North Temperate genera,Cosmopolitan genera, Old Word Temperate genera, Pantropic genera and East Asia genera, revealing the obvious temperate characteristic of this area.(3)The static life table of the S. holocarpa populations in the Yunqiu Mountains was compiled based on the population life table and the theory of survival analysis, using the age class structure represented by DBH class and smoothing out technique. The survivorship curve, mortality rate curve, vanishing rate curve and survival function curve were determined. The results showed: there were abundant middle-aged trees, but few mature individuals. Thus,viewed as a whole, the age structure of the S. holocarpa populations was growth-oriented. The S. holocarpa populations structures transitioned from growth-oriented pattern to stable pattern with the increasing of the elevation. The survivorship curve of the S. holocarpa populations conformed to Deevey type ? shape.The survival rate decreased as trees aged and the survival rate of the mature trees(?-?) decreased more quickly. The mortality rate and vanishing rate were almost in the same changing trend. Four survival functional curves showed that the S. holocarpa populations grew stably at young stage, decreased very quickly at mature stage and declined at old stage.(4) The minimum variance clustering was applied to the S.holocarpa community quantity classification. Based on the 72 quadrats dataset, the S. holocarpa community was classified into 9associations, and the basic characteristics of those associationswere discussed. The redundancy analysis(RDA) was applied to the S. holocarpa community combined with three environmental factors,elevation, gradient and aspect. Sort of RDA and minimum variance clustering produced consistent results, which better reflected the relationship between the associations and environmental factors.Environmental factors just accounted for 9.13% of the community species distribution. Based on Monte Carlo Permutation Test, the bimultivariate redundancy statistic of environmental factors were accepted, but it didn't mean that every environmental factor was significant to the species distribution. The first axis of RDA mainly reflected the change of elevation, which ascended from left to right.The second axis mainly reflected that the gradient was getting greater from the bottom to the top. Results showed that the changes in elevation and gradient were the important ecological factors affecting the composition and distribution of the S.holocarpa community species in the Yunqiu Mountains.(5)The species diversity of the 9 associations and the 3 layers of the S. holocarpa community were studied by using Patrick abundance index(S), Pielou evenness index(J), Shannon-Wiener diversity index(H) and Simpson ecological dominance index(?). The results showed that: the species diversity indexes of S, H and ? in every association were mostly herb layer > shrub layer > tree layer.However, the Pielou evenness index(J) was herb layer > tree layer >shrub layer. So it could be concluded that the S. holocarpa community species diversity in the study area was mainly affected by the herb layer. From the kernel density estimation curve, it could be seen that S, J, H and ? nuclear density curves of tree layer highlyoverlapped with shrub layer's, which infers that the changes of tree layer and shrub layer were consistent with each other. The nuclear density curve of the herb layer was wider, indicating that the herb layer was rich in a larger space, and had strong adaptability to the environment. Through distribution of box-plot, the distinction among different layers of the same diversity index was very apparent. The diversity index of shrub layer spread most widely compared with the tree layer's and herb layer's, and there were outliers in the index of J and ?. Correlation matrix analysis was carried out on the species diversity indexes, showing that there were significant positive correlations among J, H and ? indexes,between S and H, and also between S and ?. However, S had no significant correlation with J. What's more, H had the highest correlation with ? and S respectively. S and ?, J and ? took the second place. J had the lowest correlation with H and S respectively.From the trend line indicating the change of the species diversity indexes with the elevation, it could be seen that in every layer as well as in the whole community, S changed in a different trend from J, while H and ? changed in the same trend.(6)Based on 2×2 contingency table, and by using quantitative analysis methods, this paper studied the interspecific associations among the 45 dominant species of the S. holocarpa community in Yunqiu Mountains. Variance analysis showed that the 45 dominant species had no significant positive correlation with each other,which reflects that the dominant species required a relatively consistent community environment. The ?2test showed that among the 990 species pairs, 421 pairs were positively correlated, while569 pairs were negatively correlated, and the correlation ratio was0.74. Pearson's correlation coefficient test showed that 306 pairs were positively correlated, while 684 pairs were negatively correlated, and the correlation ratio was 0.45. Spearman's rank correlation coefficient test showed that 390 pairs were positively correlated, 599 pairs were negatively correlated, and the correlation ratio was 0.65. Compared to the ?2test, the Pearson's correlation coefficient and Spearman's rank correlation coefficient tests had higher sensitivity. For vast majority of the 990 species pairs, their interspecific associations did not reach significant levels, indicating that the S. holocarpa community in Yunqiu Mountains was of obvious secondary succession.