The Community Dynamics Of Recovering Process In Degraded Ecosystem Of Evergreen Broad-Leaved Forest In Daming Mountain

The key to the recovery of degraded evergreen broad-leaved forest ecosystem is the vegetation restoration. Based on the investigation of four permanent plots, which are set in the mid-mountain of Darning Mountain and are in different recovery periods, the community dynamics during the vegetation restoration are studied. Results showed that: (1) During the vegetation restoration in the mid-mountain of Darning Mountain, the plant species richness changed greatly, in the prophase period when plants settled in, plant species richness increased continually, till it reaches the climax when community are dominated by light demanding broad-leaved pioneer trees and mid-tolerance broad-leaved trees, and then, after this, the plant species richness will reduce a little, and then tend to stabilization. (2 ) The rate of vegetation restoration is quite high. In the reformed nude terra caused by deforest and controlled burning, it can evolve to the community which dominated by Alniphyllum fortunei and Castanopsis fabric after 20 years natural restoration, and to the Castanopsis fabric community which dominated by some mid-tolerancebroad-leaved trees after 30 years natural restoration. (3) Based on the similitude coefficient of communities, succession sere is constructed. (4) Height structure and diameter structure of tree layers of communities are studied, the results show that the amounts of each levels do not change evidently other than during the prophase period. (5) Measured by biodiversity index, the dynamics of community structure are studied, the results show that during the natural restoration of degrades evergreen broad-leaved forest ecosystem in the mid-mountain of Darning mountain, the biodiversity index increased quickly in the prophase period and then reduce a little but the varieties are not evident. In the prophase period the result of the biodiversity index of each levels is shrub layer > tree layer > herb layer, and metaphase is tree layer> shrub layer > herb layer, and anaphase is shrub layer > herb layer> tree layer. (6) The analysis of the dominance species population characters found that the population structures of the dominance tree species are typical increasing model and there is a trend of the distribution pattern of the dominance tree species from aggregation to random during the development process of forest climaxes. (7) The methods of Levins' niche breadth was adopted to measure the important tree species niche breadth, the results show that the niche breadth of mid-tolerance broad-leaved trees are increasing, and the niche breadth of light demanding broad-leaved trees are decreasing. (8) The frangibility of the studied ecosystem was analyzed. Theresults indicated that the restrictive factors of the ecosystem in this area are the soil factor. The ecosystem is vulnerable to be disturbed. Gaps caused by natural distribution have great influence on the restoration of the communities. During the prophase of the gap form, the biodiversity trends to decrease at first. (9) The paper comprehensively analyzed the community dynamics of recovering process in degraded ecosystem of evergreen broad-leaved forest in mid-mountain of Daming mountain, and discussed the frangibility of ecosystem and succession climax theory, and made some suggestions for the protection and the sustainable utilization of the secondary natural forest in the mid-mountain of Darning Mountain.