宁夏荒漠草原植物群落的空间异质性

Spatial heterogeneity of plant communities on desert steppe in Ningxia

荒漠草原植被最显著的特点是植物种类贫乏,几乎全部为旱生种类,且空间异质性强,植物与自然环境之间的联系密切,小地形的差异势必会造成植物群落物种多样性的变化及其在不同尺度上的空间异质性。本研究于2011年9月在宁夏盐池县试验区封育10年的荒漠草原围栏内,采用样线取样法在坡面尺度上调查不同坡位上草地群落的空间分异,分析微地形条件对荒漠草原植物群落空间异质性的影响。结果表明,植物群落的空间变异性在不同坡向及不同坡位间存在差异;矮小半灌木功能群在空间上的分布斑块化最明显,多年生草本功能群次之,一年生草本功能群在阴坡上的分布斑块化程度较高,在阳坡上其斑块性明显下降;在草地植物群落恢复演替的进程中,多年生草本植物已发展到相对稳定的程度,矮小半灌木处于增长期,一年生草本植物在阴坡的增长大于阳坡。

The most significant feature of plants on desert steppe is the deficient species, with most of them being xerophilous. These plants are of high-degree spatial heterogeneity and close to the natural environments. Differences in small terrains will inevitably lead to changes in the species diversity of plant communities and the spatial heterogeneity on different scales. Effects of different micro-landforms on the spatial heterogeneity of plant communities on desert steppe were studied in September, 2011 in the desert steppe that had been hill-closing afforested for almost ten years in the experimental area in Yanchi County, Ningxia, with the grassland communities＇ spatial differentiations in different slope places being researched in scales using line transects. The results are as the following： the spatial heterogeneity of plant communi- ties differs in different slope aspects and different slope positions; the subshrubs function group is of most obvious patchiness in the spatial distribution, perennials function group following behind; annuals function group shows a higher degree of patchiness in shady slopes but much lower in sunny slopes; as for the succession of the grassland plants function groups, the perennials function group has developed to a relatively stable state, the subshrubs function group is in the growing period, and the annuals function group grows better in the shady slopes than in the sunny slopes.