Study On Forest Vegetation Biodiversity In Typical Watershed Of Beijing Mountain Area

In the rocky mountain area of Beijing, forest coverage has increased continuously after soil and water treatment. However,some new problems have appeared. For example, the afforestration area is too large compared with natura1 forest; and planted tree species are less; proportions of pure forest, and half-mature, sapling forest are too high; forest biodiversity is low. Therefore, we have to solve the new problem in this region about how to raise forest vegetation biodiversity and then the 1evel of forest healthy according to forest vegetation succession law.In this research, we mainly research on natural secondary forest succession rule, and biodiversity in succession series. With natural secondary forest of Chaoguanxigou in Miyun county Gubeikou town as the research object, we applied three kinds of succession methods are, such as, the succession gradient analytic method, degree succession method, and the analytic method of the age grade distribution in the community, and combined with ecological niche study. Finally puts forward the biodiversity conservation measures.In this research, application quantity classification method TWINSPAN, classify to Chaoguanxigou forest vegetation in six grades. Combining 3 grades of classification systems in"China vegetation", and has built the vegetation classification system of Chaoguanxigou watershed. The forest vegetation is divided and is tied into 10 groups and 17 groups of clusters.The influence that to the vegetation distributes is bigger to altitude, soil moisture, hydrolyable N, total N and slope aspect and slope gradient etc in 14 environment factors investigated. And total K and available K, as well as total P, available P and slope position etc, and the influence that distributes to the vegetation opposites to each other unknownly to be apparent.Acoording to the research of ecological niche in Chaoguanxigou: the ecological niche is very greatly to Vitex negundo, Lespedeza bicolor, Leptodermis oblonga, Grewia biloba vra. parviflora, Ziziphus jujuba var.spinosa and Spiraea pubescens etc to Fraxinus chinensis, Ailanthus altissima, Quercus mongolica and Juglans mandshurica, for generalization plant, and Evodia daneillii, Betula dahurica malus baccata, Abelia biflora and Sambucus williamsii etc, for specialization plant.Companion that Syringa pekinensis and Carpainus turczaninowii is the Fraxinus chinensis is living and plants, and companion that Morus alba, Amygdalus davidiana and Celtis bungeana serve as the Ailanthus altissima is living and plants, Pyrus betulifolia and Carpainus turczaninowii serve as the companion of Evodia daneillii living plant . Companion for the Vitex negundo such as Leptodermis oblonga and Grewia biloba vra. parviflora, Lespedeza bicolor, Indigofera kirilowii and Ziziphus jujuba var.spinosa etc is living and is planted, puts down Corylus heterophylla mostly for Spiraea pubescens living plants, the companion of Leptopus Chinensis such as Campylotropis macrocarpa, Celastrus orbiculatus and Deutzia scabra etc living plant. Rather than and the high Pinus tabulaeformis of species niche overlap, Quercus mongolica, Tilia mongolica and Spiraea pubescens, its resources occupying rate is fairly higher in nature succession, and the competitive advantage is than greatly.By way of the investigation to the natural secondary forest in Chaoguanxigou watershed, uses the succession gradient analytic method, degree succession method, and the analytic method of the age grade distribution in the community, reaches withered tree and young tree renews condition analysis, finally combine ecological niche study and classify result ,reaches the succession law of this typical watershed forest vegetation.Succession trend on sunny slope is: The shrubbery—Koelreuteria paniculata—Prunus armeniaca var. ansu—Ailanthus altissima—Evodia daneillii—Quercus mongolica. Shady slope succession trend is: The shrubbery—Juglans mandshurica—Celtis bungeana, Ailanthus altissima, Prunus armeniaca var. ansu,—Populus davidiana, Ulmus pumila, Morus alba—Fraxinus chinensis, Syringa pekinensis—Betula dahurica—Tilia mongolica, Tilia mandshurica—Quercus mongolica, Pinus tabulaeformis. The ditch bottom succession trend is: The shrubbery—Koelreuteria paniculata—Ailanthus altissima—Evodia daneillii.Overall succession trend is: Vitex negundo—Vitex negundo, Spiraea pubescens—Koelreuteria paniculata—Celtis bungeana, Prunus armeniaca var. ansu, Ailanthus altissima—Evodia daneillii—Carpainus turczaninowii, Juglans mandshurica—Populus davidiana, Ulmus pumila, Morus alba—Fraxinus chinensis, Ulmus macrocarpa, Acer truncatum, Acer mono—Betula dahurica, Tilia mongolica—Quercus mongolica, Pinus tabulaeformis.Applying eight kinds of biodiversity measure indexes, and analysis is carried on in the community to what tide Chaoguanxigou watershed was in different succession stage. Finally, the change trend that the succession law was followed to biodiversity of each hierarchy of community is reached, as well as the law of diversity of species change between each hierarchy, and the relation between diversity indexes.In the aspects of species richness: Change a trend that moves upward is gradually appeared along with the change that succession makes progress in the community arbor layer. And the shrub layer is appeared to go up first and reduce after. But the herbaceous layer reduces back change trend that goes up for first. The richness of the arbor and shrub layer show of herbaceous layer is the clear negative correlation relation. In the community of man-made interference, the degree the richness value all is smaller than the natural community .In the aspects of species evenness: a single peak change that a change that along with succession makes progress on the community arbor layer reduces after appearing to go up first. The shrub layer evenness differs not very in each community. But the change trend of herbaceous layer is apparent in disorderly slightly. The influence not receiving the arbor layer of evenness of shrub layer And herbaceous layer the evenness suffering arbor the double influence with the bush layer of layer, and shows comparatively in disorderly. And each hierarchy of mixed forest is even degree all high than the pure forest is wanted in the community that someone worker disturbed. In the aspects of synthetical diversity: a single peak change that a change that along with succession makes progress on the community arbor layer reduces after appearing to go up first. The mutual change of each community of shrub layer is not very. That but the herbaceous layer shows reduces back change trend that goes up for first. Diversified nature of shrub layer does not suffer too many influences of arbor layer. And diversified nature of herbaceous layer shows to the clearer negative correlation relation with the arbor layer. The arbor all shows and possesses lower diversified nature with the herbaceous layer in the community that someone worker disturbed.At above three kinds of diversified nature estimate in the quota contrast, the richness index and syntheticals diversity index, assumes the notable correlation, along with diversity of increase index of the richness index also assumes the trend of increase. The richness index is very small with the correlation of evenness index, negative correlation has even to the extent that appeared. And synthetical diversity is instructed with existing the extremely notable correlation between evenness, just for the positive correlation relation .As for biodiversity conservation, not only should strengthen protecting area build, and protects species in imminent danger and kind nature resources, and defend outside kind invading, thus the community structure safeguarded reasonably promotes natural regeneration and the development of plant species, and should strengthen scientific research work, and attach importance to water and soil conservation work, theory guidances that diversified nature of thing child care made a living provides even more and the technology is put up. At the same time, still should build the law regulations guarantees systems of perfect diversified nature of living things child care, and strengthen ecology education conducing propaganda, as well as the exchange strengthened between the region between cooperation and internation, and corresponding diversified nature of the living things child care planning of formulation.