新疆塔里木河下游荒漠河岸(林)植被合理生态水位  

WATER TABLE AND THE DESERT RIPARIAN FOREST COMMUNITY IN THE LOWER REACHES OF TARIM RIVER,CHINA

作　　者：郝兴明[1] 李卫红[1] 陈亚宁[1] 

机构地区：[1]中国科学院绿洲生态与荒漠环境重点实验室

出　　处：《植物生态学报》2008年第4期838-847,共10页Chinese Journal of Plant Ecology

基　　金：中国科学院重要方向项目(KZCX2-YW-127);中国科学院西部行动计划项目(KZCX2-XB2-03);国家自然科学基金(40701011和90502004)

摘　　要：该文依据塔里木河下游地下水位多年监测资料，将地下水位按不同埋深划分为0～2、2～4、4～6、6～8、8～10和〉10m6个梯度，并设置植被调查样方进行连续监测，以分析地下水位变化对植物物种多样性与种群生态位的影响。研究结果表明：在地下水位2～4m时，物种多样性最高，其次为4～6m，再次为0～2m；当地下水位在6m以下时，物种多样性锐减，Hill多样性指数曲线变化趋势趋于平直化。荒漠河岸（林）植被主要植物种群生态位随着地下水位的逐步下降而扩展，并在地下水位4～6m处达到最宽；尔后，生态位又显著变窄；地下水位4～6m时，种群间生态位重叠最不显著，物种数较为丰富。因此，该文分析得出结论：塔里木河下游植被恢复的地下水位应确保达到6m以上，大部分地区地下水位应维持在4～6m，而部分河道附近地区地下水位争取达到2～4m。Aims Intensive utilization of water resources in the Tarim River watershed during the past five decades has reduced flows in a 320-km section in the lower reaches, drying lakes and lowering groundwater levels. This has degraded Populus euphratica forests over large areas, reducing biodiversity and impairing ecosystem structure and function. Our objectives are to study ecological responses of the natural vegetation to changes in the water table and determine the water table depth needed for the survival of desert riparian forest. Methods We divided water table depths into a gradient of six levels based on annual mean groundwater level and sampled vegetation plots for each of the six levels. We analyzed niche characteristics and species diversity of the primary populations for the six water table levels. Important findings With an increase of groundwater depth, the niche breadth of plant populations increases approximately monotonically, reaching a maximum at a groundwater depth of 4-6 m, after which the niche breadth decreases. Niche overlap is the smallest and plant species abundance highest at groundwater depth of 4-6 m. The Hill species diversity index showed highest species diversity with groundwater depth of 2-4 m, followed by 4-6 m and then 0-2 m. At groundwater depth 〉 6 m, diversity is low and the diversity curve becomes smooth. Therefore, to restore the degraded vegetation in the lower reaches of Tarim River, the groundwater depth should be at least 6 m, with 4-6 m in most areas and 2-4 m in some areas near the water course.

关 键 词：生态位宽度 生态位重叠 多样性 地下水位 塔里木河下游 

分 类 号：Q948[生物学—植物学]