三工河流域荒漠绿洲植被动态及其成因分析

以三工河流域为例，讨论了植被动态及其地貌、水资源利用、河流廊道和排碱渠等景观要素的变化对植被产生的影响．结果表明，随着景观格局的变化，流域内的植丛高度、盖度及生物量均表现出较大变异性．以河流廊道为核心，通常荒漠绿洲景观格局呈带状分布，且由内向外随水热条件的改变，植被类型由乔灌木林依次向灌丛草甸、盐化草甸、荒漠化草甸和荒漠层次结构过渡．人类活动影响强烈的景观要素。其斑块多样性、破碎度、分离度和斑块密度等指数值较高，而人类活动影响较小的，其优势度和均匀度较高．各景观要素的稳定性不同，其大小顺序为：荒漠>沙砾石地>城镇用地>水体>农田>牧草地>莱地>林地>居民点>盐碱地>荒草地>水浇地>果园．梭梭群落的净生长量高峰值出现在8月，而博乐蒿、琵琶柴群落的净生长量高峰值出现时间各年度不同．博乐蒿群落与海拔相关系数最大，而琵琶柴群落则与土壤水含量、地下水位关系密切，梭梭群落与4～9月降雨量相关系数最大。

Analysis on the dynamics of dcsert- oasis vegetation in the Sangong River Basin

Taking the Sangong River Basin as a typical research area, the relationships between the change of landscape pattern of desert-oasis and the dynamics of vegetation were studied in this paper, and the evolution of the landscape pattern of desert-oasis was also discussed. The results showed that the main characteristics of landscape pattern were the dynamics of vegetation. It had the impact on the vegetation by the changes of topography, water resources using, corridor of river and drainage channel. It was shown the great variability for the height, cover and biomass of vegetation with the change of landscape pattern. Taking the corridor of river as the center, it usually showed a zone distribution from inside to outside for the desert-oasis landscape pattern. The vegetation types evolved from the tree-shrub mixed forest, thicket meadow, salinized meadow to desert with the change of the condition of water and heat in the basin. The stability of natural patch was higher than that disturbed by mankind or manmade patch. Usually, the stability of each patch was in order of desert>sandy land>urban>pond>paddy field>grass land>vegetable plot>woodland>residential area>saline-alkali land>wasteland>farming land>orchard. The landscape pattern of desert-oasis in the research area was developed by human activities based on natural oasis.