Study On Distribution Of Rare And Endangered Species And Characteristics Of Their Communities In Beijing Mountains

Using a typical sampling method, 13 research spots such as Wuling mountain, Yunmeng mountain, Labagoumen,etc.were studied. the content of investigation includes species and its amou- nt,height,diameter at breast height(DBH), crown density, coverage, at the same time,the altitude, slope of aspect, slope position of slope were recorded. There are 403 tree plots, 27 shrub plots and 10 herb plots whichi rare and endangered species distributed are investigated.21 rare and endangered species such as Cypripedium macronthum, Liparis japonica,etc. distributing in Beijing mountains were selected as key research objects. Numerical classification and sorting of the vegetations rare and endangered species distributed was used to divide into different Formation and association, then characteristics of communities were studied;The distributing law of rare and endangered species with topographic factors (altitude, slope of aspect, slope) and communities diversities were analyzed. Niche of rare and endangered herbage species distributed in forest vegetations of Beijing mountainous region, Population structure of dominant species distributing in rare and endangered communities and interspecies association between the main dominat species, the conservation priority of protected areas based on rare and endangered species conservation, those were studied.The objective of this paper is to provide scientific methods and theories for rare and endangered species conservation. The following results have been obtained in this research.(1) Two-Way Indicators Species Analysis (TWINSPAN) and Detrended Correspondence Analysis (DCA) are used to study the distribution of forest vegetation rare and endangered species distributed. TWINSPAN classification results show that the forest vegetation can be divided into 67 association, such as Carex lanceolata-Spiraea trilobata-Quercus mongolica association, Carex lanceolata-Corylus heterophylla-Populus davidiana association,etc.They belong to 2 vegetation type groups, such as coniferous forest and broadleaf forest;2 vegetation types, such as cold temperate coniferous forest and defoliation broadleaf forest;19 formation, such as Pinus tabulaeformis forest ,Populus davidiana forest, Juglans mandshurica forest,etc. There are 10 formation and 12 association rare and endangered species distributed and species number﹥3.(2)Rare and endangered species concentrate in 10 formation, such as Betula platyphylla formation, Juglans mandshurica formation, etc. Species richness and diversity in tree,shrub,herb three different layers of different communities are calculated. The results show that species richness index, Simpson index, Shannon-wiener index are the lowest in tree layers, the medium in shrub layers, the highest in herb layers. This reflects the characteristics of vegetations in warm temperate zone in Beijing mountain.In tree layers, evenness index and species diversity index are higher in Tilia amurensis formation, and speices diversity index of Quercus mongolica formation, while Larix principis-rupprechil formation and Pinus tabulaeformis formation are lower. In shrub layers, there is no a significant difference between species richness of 10 formation, species diversity in Quercus mongolica formation, Pinus tabulaeformis formation,etc. are higher than other communities. In herb layers, there is a significant difference in species richness between different communities. The total species diversity are higher in Juglans mandshurica community, Populus davidiana community, Pinus tabulaeformis community and the number of rare and endangered species distributed is bigger, but lower in Carpinus turczaninowii community and the number of rare and endangered species distributed is smaller.(3)The distributing law of rare and endangered species with topographic factors (altitude, slope of aspect, slope) shows that①The number of rare and endangered species is increasing along with the elevation rising, but the elevation continue to rise, the number is decreasing. This shows a rule of"Mid altitude bulge"with change of altitude. the peak bias to medium elevation and appear in 650m-950m and 1150m-1450m.②The number of rare and endangered species in different slope of aspects is north aspect﹥northwest aspect﹥northeast aspect﹥west aspect﹥east aspect﹥south aspect﹥southwest aspect﹥southeast aspect. The species number in shady and half shady slope of aspect is more than in sunny and half sunny slope of aspect. The distributing frequency of species in different slope of aspects is correlated with its biological and ecological characteristics,thus result in different habitat request. The species number is the most in slope 5-10°and 25-30°. the similarity indexes of distributing rare and endangered species in slope grade between 5 and 2,3,4,6 is higher, this shows that slope grade 5 is important. So the 20-30°slope is concentrated distribution area of rare and endangered species.(4)The similarity indexes of different 11 commmunities rare and endangered species distributed are analysed. The result shows that the similarity index is higher between Juglans mandshurica community and Pinus tabulaeformis community, thus two communities are important in species conservation.The importance value of the same species in different communities or different species in the same community is variant, because the difference of ecological and biological characteristics of species, it leads to choice different habitats.(5) Among some communities dominat speices of rare and endangered species distributed, Juglans mandshurica community distribute in Wuling Mountain Nature Reserve of Beijing mountain as a research object. Inter-species and intra-species associaton are studied. The results showed that Juglans mandshurica population in the canopy was positively associated with that in the subcanopy, but significantly and negatively associated with Syringa pekinensis population in the understory and the association coefficients were large. Compared with the number of species-pairs with the positive associations, fewer negative associations were found between Juglans mandshurica population with others in three vertical layers, while the number of species-pairs with the positive associations was greater than with positive association between Juglans mandshurica population in the subcanopy with others in three vertical layers.(6)A total of 42 plots of forest communities where rare and endangered herbage plants distribute are collected from investigating plots in Beijing mountainous region. With the importance value as the resource state descriptor of the niche, the niche breadths and overlaps of Glycine soja, Cypripedium macranthum, Malaxis monophyllos, Herminium monorchis, Oresitrophe rupifraga, Paeonia obovata, Platanthera chlorantha and Liparis japonica 7 species of rare and endangered herbage plants in Beijing mountainous region are calculated and analyzed. Then discovering efficiency of population make use of resources and ability of population adapt to environment. The results show that the niche breadths of Glycine soja is bigger, 0.297; but Cypripedium macranthum, Malaxis monophyllos, Herminium monorchis at the same orchidaceae are smaller, this indicate the amount of orchidaceae plants and types of forest vegetation community where they distribute in and suitable habits that live in are smaller, thus these species are anxious to priority conservation. In general, the niche overlaps between the species with bigger niche breadth and other species are higher, and those of the species having similar environmental requirements are also higher.(7)The minimum number of distribution units based on rare and endangered species protection are determined with the parsimony analysis of endemicity (PAE) and the complementarity analysis. Speices richness index and rare and endangered species protection in 12 sites as indexes are used to assess priority order, indexes determined, weight sum , then priority order of different regions were determined according to scores values. The first order priority regions are Song mountain nature reserve and Baihua mountain nature reserve;the second order priority regions are Labagoumen,Wuling mountain,Yunmeng mountain nature reserves and Mutianyu scenic spots;the third order priority regions are Puwa,Yunmeng mountain nature reserves and Shidu,Miaofeng mountain,Shihuadong,Tanjiesi scenic spots.