黄土区土坎植被群落草本优势种的种间关联性研究

以黄土区典型土坎植被群落为研究对象，筛选25种草本优势种，采用方差比率法，结合χ²检验、联结系数AC、共同出现百分率PC和Spearman秩相关分析方法，分析25个草本优势种的种间关系，为重力侵蚀治理、固沟保塬的植物配置提供理论支撑和技术依据。结果表明:1）方差比率法的检验结果表明，25个草本优势种总体上种间关系呈现显著正关联；2）χ²检验结果表明，正关联种对数（163）高于负关联种对数（135），且显著关联的种对数占总种对数的6.67%；3）大部分种对间联结系数AC和共同出现百分率PC都不高，种对间的相关性较弱，联结关系松散，群落仍处于长期的发展过程中；4）根据Spearman秩相关系数对25个优势种进行聚类分析，可将其划分为5个生态种组。

Interspecific Association of Dominant Herb Species in Ridge Vegetation Community in the Loess Area

The typical ridge vegetation community in the loess area was taken as the research object in this study.Twenty-five dominant herbaceous species were screened out.The interspecific relationships among the 25 species were analyzed by variance ratio method,combined with χ²-test,connection coefficient AC,co-occurrence percentage PC and Spearman rank correlation analysis method to provide theoretical support and technical basis for gravity erosion control and gulley fixation and tableland protection.The results were as follows.1) Generally,the variance ratio method showed that 25 herbaceous dominant species presented significant and positive correlations.2) The χ²-test showed that the logarithm of positively associated species was higher than those of negatively associated species,and the proportion of species-pairs with significant correlation was 6.67%.3) The connection coefficients and the percentages of coexistence of most species-pairs were not high,indicating weak association,and the community was still in the long-term development process.4) Based on the Spearman rank correlation coefficient and cluster analysis,25 dominant species could be divided into 5 ecological groups.