| From May 2009 to September 2010, we carried on collecting plant specimens, investigating vegetation and quadrat survey to subalpine meadows of Dongling Mountain in Beijing. Based on examinating plant specimens, consulting literature and analyzing quadrat data, this dissertation has made a thorough research on the floristic characteristics of vascular plants, plant diversity and human disturbance effect in the area. This study may provide some scientific bases for appropriately exploiting, conseving and rehabilitating the subalpine vegetation of Beijing. The main results of the research are as follows:1. There is a relatively abundant flora in this region.280 vascular plants represented in the study area (about 27 square kilometers, above 1900 m), account for 15.64% of the total wild vascular plants (1790 species) in Beijing. These plants belong to 161 genera and 46 families. Among these, the pteridophytes include five families with six genera and six total species; and the gymnosperms include only a single species. The angiosperm flora is more diverse, consisting of 40 families with 154 genera and 273 species. In addition,1 new record of Beijing,4 fonns with multiplicate flowers and 3 forms with white flowers have been found.2. Geographic elements are complex. The genera and species can be independently divided into 12 distribution types, covering 15 distribution types (Wu Zhengyi). The flora shows an obviously temperate feature. Temperate-areal type genera account for 93.18% of the total genera that are not cosmopolitan. Temperate-areal type species account for 70.04% of the total species that are not cosmopolitan, and they are main components of this region vegetation. In addition, the great majority of the species endemic to China, which account for the greatest number, mainly distribute in temperate zones. At family, genus and species level, the flora shows temperate characteristics and few tropical origin relationships.3. With no endemic family and genera, species endemic to China are rich, accounting up to 26.79% of the total species in the area. Of these, some taxa are narrowly endemic to Dongling and Xiling Mountain and North China. Also, some species not found in other mountain areas in Beijing, such as Caragana jubata, Spiraea mongolica, Comastoma pulmonarium and Mertensia davurica, only exist in this area. Therefore, plant germplasm resources of subalpine meadows in Dongling Mountain have an important value.4. Herbaceous chamaephytes, hemicryptophytes and geophytes are dominant,233 species, comprising 83.21% of the total, that is adapted to harsh, subalpine habitats. Annual herbs amount up to 10.00% of the total species in the area, indicating that subalpine meadows of Dongling Mountain have been disturbed by some human effects.5. According to the vegetation classification system of "Vegetation of China"(1995), main communities in the area are divided into 2 vegetation types,5 shrub formations,3 meadow formation groups(8 meadow associations). Plant diversity in the shrub layer of shrub communities is lower than its herb layer; differences of plant diversity between the herb layer of shrub communities and meadow communities are not significant; there exist obvious differences among the 8 meadow community types. As far as the shrub layer of shrub community types is concerned, plant diversity of Form. Syringa villosa is the highest; the shrub species of Form. Caragana jubata are seriously single and its plant diversity is the lowest. Among the 8 meadow associations, plant diversities of Ass. Poa sphondylodes + Carex capilaris + Polygonum bistorta and Ass. Dendranthema chanetii + Carex lanceolata + Saussurea ussuriensis are higher, followed by Ass. Carex capilaris + Poa sphondylodes and Ass. Anemone cathayensis + Carex lanceolata. Ass. Plantago depressa + Carex capilaris + Polygonum aviculare is formed with human disturbance; thus its dominance and evenness are relatively low.6. Excessive and disordered mining, grazing and tourism has obviously destroyed the habitats, community structure and plant diversity of subalpine meadows in Dongling Mountain. The farther from the major tourism path, plant species composition and plant diversity have obvious increasing tendency. Plant communities nearest the major tourism path have been disturbed most strongly; minority of anthropophilic plants are dominant, so as that the evenness index is the lowest and community stability is lower. Some strategies are proposed for the protection and regeneration of vegetation, such as scientifically programming tourism area, establishing an independent natural reserve, strengthening publicity and controlling grazing.7. Plant resources are fairly abundant. There are 83 edible plants,86 medicinal plants,40 industrial plants,145 ornamental plants and 30 poisonous plants.16 key protected plants are surveyed, which is 16.33% of Beijing key protected plants (98 speices).
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