Study On Distribution Pattern And Interspecific Association Of Forest Communities In Xiaolong Mountain National Nature Reserve

Plant ecology means significantly not only in the development and utilization, restoration andprotection of forest ecosystem but also in the maintenance of ecological balance as well as inpromoting the sustainable development of ecology. Distribution pattern and Inter-specificassociation are two major branches of plant ecology.Distribution pattern is the distribution and configuration of each individual species, is theresult of the interaction and mutual relationship between species. Using t-test of variance/meanratio, negative binomial distribution parameter (k), aggregation index (I), Cassie index, poly blockindex (PAI), diffusion index (I_δ), and other methods, this paper analyzed the distribution patternof non-dominant species in mountain XiaoLong national nature reserve including Platycladusorientalis (Linn.) Franco, Betula albo-sinensis Burk., Castanea mollissima Bl., Fraxinusplatypoda Oliv.. Studies have shown that the four species present a aggregated distribution.Among the Plots, the percentage of young Platycladus orientalis (Linn.) Franco. is broadly higherthan that of the middle-aged tree and old seedling, and the entire species is in steady growth.Thedevelopment of Betula albo-sinensis Burk. is relatively mature, which has shown itscomparatively weak immunity against pests and natural catastrophes, and its declining trend in themeantime. Castanea mollissima Bl. is in a stable stage, during which has a high resourceutilization, and a moderate inter-specific competition. In a long run, it can become dominantspecies or companion species, as the change of age structure, its aggregation will eventuallychange. For Fraxinus platypoda Oliv., its negative binomial distribution parameter (k) is onlysmaller than Betula albo-sinensis Burk.. It also showed a trend of decline, its degradation degree isless than Betula albo-sinensis Burk. but in a considerrate population diversity with Betulaalbo-sinensis Burk. and has a certainly stable population structure.Interspecific association is caused by the species distribution and differences influence of thedifferent biotope, which reflecting the organic connection of different species in different habitat,during which each factors is connected with the other. Inter-specific association have importanttheoretical value and practical guiding in breeding diffusion mechanism and precaution of plantpopulation. This article use multiple index to characterize the correlation between species: whenmeasuring compound correlation between species, we use variance ratio method (VR), whenmeasuring paired species, we use2x2linked list, and Yates continuity correction formula, when measuring polarity correlation, we use PC, AC. when measuring the inter-specific association, weuse Ochiai index, Dice index and Jaccard index. At the same time, combined with the Pearsoncorrelation analysis and the Spearman rank correlation analysis and other methods. The researchindicates: Platycladus orientalis (Linn.) Franco. community have a non-significant negativecorrelation, its inter-specific association is not tight, its community ecological structure is varying,the competition among different species are fierce, in all, it in the early stages of the successionprocess. For Betula albo-sinensis Burk. and Castanea mollissima Bl., species relationship isconsistent within the community environmen, the inter-specific relationship is confirmed,community structure is relatively stable and mature, belonging to the recession type; Interspeciesrelation of Betula albo-sinensis Burk. is determined, the community structure is relatively stableand perfect, undergoing to the mature forest. To obtain more stable coexistence between species,whose the relationship between dominant species is close. For Fraxinus platypoda Oliv.community, its multiple co-relations have significant negative correlation, which the community isspaced out, and have a fierce competition, and have a high allelopathy, raising a strict request forthe differential environment. According to different species habitat, we divided it into three groups:group of heliophilous, high tolerant to drought, and adret, Group of fond of shade, retirement,schattenseite, valley. Forest margins or shrub widely distributed group. we conclude a Intuitiveperformance for the relationships bettween species through the division of ecological speciesgroup for the Associated species, and combined with the analysis of connection between species.