Abstract:

Understanding the relationship between surface pollen and modern vegetation in the Tianshan meadow is of great importance for interpreting Quaternary environmental evolution based on stratigraphic pollen. In this study, three types of meadows (middle mountain meadows, subalpine meadows, and alpine meadows) along the north slope of West Tianshan Mountain were selected as the research objects, and 54 surface pollen samples from 9 plant communities were taken as the research materials. The relationship between surface pollen and modern vegetation along the north slope of West Tianshan Mountain was discussed based on the pollen identification results and field sample survey data. The ecological environment indication significance of pollen and vegetation was revealed based on the Detrended Correspondence Analysis. The results showed that the proportions of Picea, Chenopodiaceae, and Artemisia were high among the surface pollen samples, at 20.7%, 18.2%, and 17.1%, respectively; they affected the discrimination of the relationship between surface pollen assemblage and modern vegetation. In addition, Poaceae, Cyperaceae, Rosaceae, and Compositae had high content levels in the communities with their own constructive or dominant species, at 12.1%, 9.6%, 7.8%, and 4.9%, respectively. There were unique pollen assemblages in each vegetation zone. The middle mountain meadow was characterized by Picea-Poaceae-Chenopodiaceae-Artemisia, and the subalpine meadow evolved into Picea-Artemisia- Chenopodiaceae-Rosaceae-Poaceae. The alpine meadow was composed of Chenopodiaceae-Cyperaceae-Artemisia-Picea-Poaceae pollen assemblages. The ratio of Poaceae/(Artemisia+Chenopodiaceae) and Cyperaceae/(Artemisia+Chenopodiaceae) not only distinguished middle mountain, subalpine, and alpine meadows, but also indicated the humidity and temperature. Detrended Correspondence Analysis and Cluster Analysis can thus be used to divide samples into their own communities. Temperature and humidity are important ecological factors on the northern slope of the Western Tianshan Mountains.

Key words: meadow, surface pollen, modern vegetation, cluster analysis, detrend correspondence analysis, the north slope of Tianshan

摘要：

厘清天山草甸表土花粉与现代植被的关系,对用地层花粉解译该区第四纪环境演变具有重要意义。选取西天山北坡3类草甸（中山草甸、亚高山草甸、高山草甸）为研究对象,以9个植物群落的54个表土花粉样品为研究材料,依据花粉鉴定结果,对比野外样方调查数据,探讨了西天山北坡草甸表土花粉与现代植被的关系,基于除趋势对应分析方法揭示了花粉、植被的生态环境指示意义。研究表明,（1）云杉属（Picea）、藜科（Chenopodiaceae）、蒿属（Artemisia）在表土样品中含量高,分别为20.7%、18.2%、17.1%,影响了表土花粉组合与现代植被关系判别。禾本科（Poaceae）、莎草科（Cyperaceae）、蔷薇科（Rosaceae）、菊科（Compositae）花粉在以各自为建群种或优势种的群落中有较高含量,分别为12.1%、9.6%、7.8%、4.9%。（2）各植被带均存在特有的表土花粉组合,中山草甸以云杉属-禾本科-藜科-蒿属为特征,亚高山草甸演变为云杉属-蒿属-藜科-蔷薇科-禾本科组合,高山草甸由藜科-莎草科-蒿属-云杉属-禾本科花粉组成。（3）禾本科/(蒿属+藜科)、莎草科/(蒿属+藜科) 比值可用于区分中山草甸、亚高山草甸、高山草甸,还可分别指示湿度大小和温度高低。（4）除趋势对应分析、聚类分析能将表土花粉样品划分至各自群落。温度、湿度为西天山北坡重要的生态因子,温度促使植被带形成和分布,湿度使其进一步分化形成了不同群落。

关键词: 草甸, 表土花粉, 现代植被, 聚类分析, 除趋势对应分析, 天山北坡