Studies On The Vegetation Characteristic And The Effects Of Engineering Construction On Vegetation Diversity Along Qinghai-Tibetan Railway

Qinghai-Tibetan plateau have an unique system with high altitude, draught, rare air and cold climatic. These factors brought about it's sensitive and fragile. The recovery would be more difficulty if it was damaged. In this paper, floristic characteristics, vegetation regionalization and the influence made by the railway construction were researched and it would be theorized groundwork and practiced gist for the recovery of the community along the Qinghai-Tibetan railway.Floristic characteristics were made by Wu zhengyi's research into the areal-types of genera of Chinese seed plants. The results indicated that there were 38 families, 133 genuses, 287 species and varieties along the Qinghai-Tibetan railway. As for the analysis of family, the dominant species focus on the big large-sized and middle-sized families (sum of these two families account for 71.43% of the total species) .In terms of genus,the type of Temperate Zone was the most( 72.18%) and the Endemic to China was the least(3.76%). Mostly the types of plants belong to the southwest, and fit for the environment with rare air, cold climatic and high altitude.Vegetation regionalizations were made by adopting ecology classify andβ-diversity index method. They are 6 vegetation regions are classified: desert region,alpine grassland region,secondary alpine grassland region,alpine meadow region,the alternative belt of alpine meadow and alpine grassland and shrub-grassland region.When taking the railroad as the center, the influence of community under the different disturbance degrees was researched. The results show that there were relatively less dominate species because of its peculiar environment, just 29 species in all. The crease of Species richness with creasing elevation has been observed in the lighter sides and the heavier sides, and the change of Shannon-Wiener index was basically same with Species richness. There were not differences evidently between the both sides in Pielou index but the Simpson index goes the reverse way. The changes ofβdiversity among communities tend to be consistent, and there was little influence obviously by human disturbances. The changes of communities along Qinghai-Tibetan railway under two different disturbance degrees is finitude relatively.The influence of railway construction on the permafrost ecosystem was researched. The result show that the changeable trends of the Pielou index was similar to the Shannon-Wiener index at 5m,25m, 75m in perpendicular direction to the railway, both of them went the same way: increasing at the beginning and then decreaseing. At 150m and 300m, the Pielou index took on the increasing way again. The most obviously influence made by railway construction at the second plot and the least was far away from the 75m.Sum up all the researches, some advices were put forward.