青海湖地区植被及其分布规律

 青海湖地区位于青藏高原东北部。境内复杂的地貌类型及青海湖的存在对植被有重要影响。本区植物种类贫乏，现有种子植物52科、174属、445种。主要植被类型有寒温性针叶林、高原河谷灌丛、高寒灌丛、沙生灌丛、温性草原、高寒草原、高寒草甸、沼泽草甸、高寒流石坡植被等。植被分布表现出明显的规律性变化。草原分布于湖盆及河谷地带，由东而西植被类型有更加适应寒旱趋势。温性草原以青海湖为中心；呈环带状分布，而高寒草原的分布则与生境寒冷干旱相一致。山地垂直带谱表现为草原带、高寒灌丛与高寒草甸带以及高寒流石坡植被带。本区植被水平地带性分异受到青海湖的影响，其植被组合及特征表现出与青藏高原植被的明显相似性。作为祁连山南麓中部地区的一个大型山间盆地，其东西方向界于青海省东部地区和柴达木盆地之间，植被东西方向的水平地带性并未表现出明显的过渡特征。根据植被特点及分布规律分析，本区植被有其自身的特殊性，并与青藏高原隆升之后气候寒冷干旱相一致。因此，青海湖地区就整体而言应属祁连山地区植被一个相对独立的组成部分。

TYPES AND DISTRIBUTION OF VEGETATION IN QINGHAI LAKE REGION

The Qinghai Lake region is located in the northeastern of Qinghai-Xizang Plateau, about 36?15′—38?20′N,97?50′—101?20′E. The elevation of this region is about 3200--5000m about sea level. The vegetation and its distribution in this region was influenced by the existence of Qinghai Lake and the complicated landscape characteristics. Plant species growing in the area is poor. According to preliminary statistics, there are 52 families, 174 genera, 445 species of spermatophytes. The main vegetation types are. needleleaf forest in cold temperate, shrubs in plateau valley, alpine shrubs, sandy shrubs, steppe in temperate, alpine steppe, alpine meadow, swamp meadow, subnival vegetation, and so on. The characteristics of the communities above are described in this paper. The distributional law of vegetation in this region is evident. The horizontal variation of vegetation shows a trend of adapting high-cold habitats from east to west. The temperate steppe, which is distributed in a ring-shaped belt around the lake, is related to the lake basin landscape and the existence of Qinghai Lake. The alpine steppe is found within high-cold habitats. The vertical spectrum in this area from down to up shows steppe-alpine shrubs and alpine meadow-subnival vegetation.As a whole, the region belongs to one part of Qilian Mountains area, and is between the eastern region in Qinghai Province and Qaidam Basin. Based on analysis, vegetation and distribution in Qinghai Lake region has a special pattern and coincides with the climate trends to colder and droughter with the uplift of Qinghai-Xizang Plateau. With all these in mind, we suggest that the Qinghai Lake region, is a relatively independent part of Qilian Mountains area.