藏北草地资源及其演化趋势——以申扎地区为例  

Resources in grassland of northern Tibet and its evolutionary trend-a case study of the Zainza area

作　　者：李才[1] 翟庆国[1] 徐锋[1] 朱志勇[1] 王天武[1] 

机构地区：[1]吉林大学地球科学学院,吉林长春130061

出　　处：《地质通报》2003年第11期991-998,共8页Geological Bulletin of China

基　　金：青藏高原1:25万申扎县幅地质调查项目(20001300009141)部分成果。

摘　　要：申扎地区属青藏高原南羌塘高寒草原区,具有典型的高原植被。根据水体条件、植被组成和地貌特征等,划分了7种草地植被类型和2个木本植物分布区。藏北地区生态系统十分脆弱,高原植被面临严峻的破坏、退化和沙漠化环境,生物链严重失调,高原鼠兔由于几乎没有天敌而大量繁殖。对高原草地的破坏因素进行分析认为:高寒、冻融作用、地下水位下降、雪线上升和冰川萎缩、猖獗的鼠害、超载过牧是高原植被(草地)退化的主要因素,其中高寒、缺水、鼠害和超载过牧是最重要的原因。藏北申扎地区年降水量与年蒸发量比例为约1∶9,湿地和植被供水系统受到严重损害,造成大面积草场萎缩,形成了环状草地退化带。藏北草地向恶化方向发展是不可逆的,根治鼠害,改良牲畜品种,提高经济效益,可以减缓草场退化速度。The Zainza area,a high and cold prairie area in south Qiangtang,Qinghai-Tibet Plateau,is covered with typical plateau vegetations.According to the hydrological conditions ,vegetation species and landform characters,seven grassland types and two zones of woody plants are distinguished.The ecological system in northern Tibet is extremely weak.Plateau vegetations and wetland are now facing severe damage,degeneration and desertification.The biological chain is seriously out of harmony.Rats and hares reproduce in large quantity because of almost no natural enemies.Analysis shows that the main factors of the degen-eration of vegetations and wetland are the high altitude and coldness,shortage of water,plague of rats and overgrazing.The proportion between the annual precipitation and annual evaporation in the Zainza area is about 1∶9.The water supply system of wetland and vegetations has been damaged seriously,resulting in ex-tensive shrinkage of grassland and formation of ring-shaped grassland degeneration zone.It is generally ac-cepted that the deterioration trend of the grassland in northern Tibet is irreversible.However,the degener-ation rate of the grassland can be slowed down by some effective measures such as elimination of the plague of rats,improvement of the breed of livestock and raising of economic benefits.

关 键 词：藏北地区 南羌塘高寒植被区 生态系统 植被类型 发展趋势 申扎地区 草地资源 演化 

分 类 号：X141[环境科学与工程—环境科学] X17