青海湖流域草地植被与物种多样性空间分异研究

Spatial differentiation of grassland vegetation and species diversity in Qinghai Lake basin

摘要:

【目的】揭示青海湖流域草地植被及物种多样性的空间分异规律。【方法】基于野外调查和遥感技术对草地进行分区，采用 Patrick 丰富度指数、Shannon-wiener 多样性指数、Pielou 均匀度指数和 Simpson 优势度指数分析各类型区物种多样性和重要值。【结果】1）青海湖流域草地主要以禾本科、菊科及莎草科为主。温性草原优势种以芨芨草、短花针茅和西北针茅为主；中海拔的高寒草地形成以冰草、冷蒿和紫花针茅为优势种的草地类型；高寒草甸以嵩草属为主，形成了高山嵩草、矮嵩草、北方嵩草、线叶嵩草草地类型。2）低盖度区以紫花针茅和北方嵩草为优势种，具有耐寒、耐盐碱特点；中盖度区优势种为高山嵩草、线叶嵩草、藏嵩草；高盖度区多以芨芨草、克氏针茅、紫羊茅为优势种，群落结构层次明显。3）不同盖度分区的丰富度指数、多样性指数和均匀度指数呈低盖度（VFC＜0. 3）＜中盖度 （VFC0. 3~0. 6）＜高盖度（VFC＞0. 6），优势度指数呈相反趋势。4）不同草地类型：丰富度指数、多样性指数，形成了“低-高-低”的单峰曲线，在高寒草原区较高，分别介于（0. 659~2. 897）和（5~26）；高寒草甸均匀度指数较高（0. 146~0. 919）。【结论】盖度对草地物种多样性的影响较小，不同草地类型物种多样性主要受海拔影响，所以海拔是影响青海湖流域草地植被与物种多样性的主要因素。

Abstract:

【Objective】 To reveal the spatial differentiation of grassland vegetation and species diversity in Qinghai Lake Basin.【Method】The Patrick richness index，Shannon-wiener diversity index，Pielou evenness index and Simpson dominance index were used to analyze the species diversity and importance values of the grassland based on field survey and remote sensing.【Result】1） Grasses，Compositae and sedges were dominant in the grassland of Qinghai Lake Basin. The dominant species in warm steppe are mainly Achnatherum splendens，Stipa breviflorum and Stipa Splendens. . In the middle altitude alpine grassland，the dominant species of the grassland were grass，artemisia frigida and Stipa purple. The alpine meadow was mainly composed of kobresia，kobresia alba，Kobresia alba，Kobresia borealis and Kobresia alba. 2） In the low coverage area，Stipa purple and Kobresia boreal were the dominant species， which had the characteristics of cold tolerance，salt and alkali tolerance. In the middle coverage area，the dominant species were kobresiaaltifolia，Kobresiaaltifolia and Kobresiaaltifolia. In the high coverage area，the dominant species of Achnatherum Splendens，Stipa clari and Fescue purple were mainly found，and the hierarchy of community structure was obvious. 3） In different coverage regions，richness index，diversity index and evenness index showed low coverage （VFC＜0. 3），medium coverage （VFC0. 3~0. 6） and high coverage （VFC＞0. 6），while dominance index showed opposite trend. 4）The richness index and diversity index of different grassland types formed a unimodal curve of "low，high and low"，which was higher in the alpine grassland area，ranging from（0. 659~2. 897）and（5~26），respectively. The evenness index of alpine meadow was higher （0. 146~0. 919）.【Conclusion】The results showed that the coverage had little effect on grassland species diversity，and the grassland species diversity of different grassland types was mainly affected by altitude. Therefore，altitude was the main factor affecting the grassland vegetation and species diversity in Qinghai Lake Basin.