Spatial Variation Of Species Diversity Within Community In A Lower Subtropical Ever-green Broad-leaved Forest, South China

The spatial variation of species diversity in a subtropical ever-green broad-leaved forest was studied comprehensively in terms of flora characteristics, quantitative characteristics, species diversity, niche and spatial pattern in Subtropics, South China. The results are follows: 1．Heishiding Natural Reserves, which is situated in the Lower Subtropical region of China, consists of 1506 species belonging to 160 families and 618 genera. In its flora, 6 species, 5 families and 5 genera are gymnosperm, 1500 species (and varieties) and 155 families, 613 genera belong to angiosperm; some flora of the rare plants in this region have ancient origin original; It is predominated by tropical elements and subtropical elements (account for 75.48% of total number of genera), and is also affected by temperate elements (16.52%); some pan-tropical and tropical species are close to the northern boundary of their distribution areas; therefore the typical elements of the flora were obviously characterized by the tropical and sub-tropical and temperate elements.2．Species richness, species evenness and species diversity were studied, also with their spatial distribution trends. Within the 2.18hm2 plot, the richness and abundance of trees are various in each quadrat. The small-scale difference of species diversity among quadrat groups along the altitude from valley to hilltop gradually reduced. There is a small fluctuation in a certainty scope on horizontal grads.3．The species height, diameter class structure and tree species diversity were examined. The tree species richness and diversity indexes were high relative to forests in mainland China. Both the numbers of tree species and tree density decreased as height class or diameter class increased, fitting both negative exponential and negative power equations. There was a significant positive correlation between tree species abundance and tree density for trees of different height classes.4．Spatial distribution of the species importance value was studied and the importance value of Cryptocarya concinna was heavy and changes little in the space. The importance value of the main companions mainly embodied in the gradually risewith the rise of the altitude from the valley to the hilltop.5．Species niche on community gradient. On the resource array from valley to hilltop of community gradients of the environmental factors Include height, sunshine, moisture and so on, both of the niche breadth and niche overlapping are heavy, and the Cryptocarya concinna is the on the first place. Environment conditions of community quite adapt the growth of the plant. Most populations can utilize various kinds of resources and their population ecological similarity is heavier and there is considerably ecological substitutability.6．Most plant emerged aggregation distribution in study of spatial pattern and attributes it to the space heterogeneity and plant physiological characteristic and renewal and succession of the whole forest.7．Spatial structure of ever-green broad-leaved forests in Subtropics, South China is quite complicated and is typical of heterogeneity, irregularity and non-homogeneous. Research on spatial pattern of species diversity of plant community only combined with analysis of flora characteristics, quantitative characteristics, species diversity, niche and spatial pattern can improve the better understanding of overall regional plant community diversity.