天山南坡高寒草地海拔梯度上的植物多样性变化格局

Plant species diversity of alpine grasslands on southern slope of Tianshan Mountain along altitude gradient.

山地气候随海拔梯度变化使山地成为研究生物多样性的热点区域。在天山南坡巴音布鲁克高寒草地，对不同海拔梯度下的物种多样性进行了研究。结果表明：共调查样地9个，出现植物34种，分属17科29属；物种丰富度随海拔升高呈明显的偏峰格局，在海拔3060m的天山羽衣草（Alchemilla tianschanica）草甸，物种组成最为丰富，出现植物17种，分属12科17属；Shannon—Wiener指数的变化范围为2．02～2．40，最小值出现在海拔2760m以紫花针茅（Stipapurpurea）为优势种的高寒草原，峰值则出现在3060m的天山羽衣草草甸，Shannon—Wiener指数随海拔梯度的变化趋势与物种丰富度基本相同，呈明显的偏峰格局；随海拔升高，Cody指数表现出明显的单峰格局；Shannon—Wiener指数与生长季温度存在显著负相关，而与生长季湿度和土壤含水量存在显著正相关。

Climate alteration due to altitude gradient makes mountain biota a hotspot of biological richness research. The study on the plant species diversity of Bayanbulak alpine grasslands on the southern slope of Tianshan Mountain showed that at 9 sampling sites along altitude gradient, a total of 34 species was recorded, belonging to 29 genera and 17 families. The species richness along altitude gradient presented partially unimodal pattern, being the maximal on the AlchemiUa tianschanica grassland at 3 060 m, with 17 species belonging to 12 families and 17 genera. The Shannon-Wiener index also showed a partially unimodal pattern. Its variation range was 2.02 - 2. 40, with the maximum on the A. tianschanica grassland at 3 060 m and the minimum on the Stipa purpurea grassland at 2 760 m. The Cody index along altitude gradient presented unimodal pattern. Shannon-Wiener index was negatively correlated with the temperature, while positively correlated with the relative humidity and soil moisture content in growing season.