植物种间联结研究内容与方法评述

A review of contents and methods used to analyze various aspects of plant interspecific associations

植物种间联结是植物群落重要的数量和结构特征之一,是植物群落结构形成和演化的基础。研究种间联结,对于植物群落的稳定与演替、植被的恢复与重建等具有重要的理论意义和应用价值。为了便于探讨种间联结的形成机制,本文评述了种间联结的研究内容、计算方法及其影响因素,同时指出了现研究存在的问题及今后的研究方向。植物种间联结受多方面因素影响,既有人为取样尺度的影响,又有环境与生物自身的因素。在群落演替的不同阶段,种间联结性往往有所不同。为此,可采用多尺度排序法分析不同尺度格局上复杂的种间联结关系,重点加强植物"利他作用"及入侵种种间联结的研究。在Fisher精确检验的基础上,结合Pearson相关系数和Spearman秩相关系数来检验种对间的相关性,并利用生态位理论或从植物生理、分子遗传的角度研究密度主导的种间联结的变化,可以准确揭示植物种间的内在关联性。

Plant interspecific associations, which are significant quantitative and structural characteristics, are crucial for the formation and evolution of plant communities. Studying interspecific associations provides vital theoretical and practical avenues for understanding the stabilization and succession of plant communities, and for their restoration and reconstruction. To understand the formation mechanisms underlying interspecific associations, the methods commonly used to analyze the factors influencing plant interspecific associations were reviewed; then, the main problems with recent studies were discussed. Five aspects of interspecifie associations were reviewed： facilitation, invasion, identifying species groups, different stages of succession, and different patterns of scale. Commonly used analytical methods, which involve calculations based on the number of individuals found in a set of plots, include the covered variate ratio, x2 test, Fisher exact test, Pearson correlation coefficient, Spearman rank correlation coefficient, association coefficients, matching coefficients （Jaccard, Dice, and Oehiai coefficients ）, point correlation coefficients, and coupling values. However, interspecific associations are affected by multiple factors, including artificial sampling scales, environmental factors, and biological factors. 0rganismal properties affect interspecific association, which can in turn affect competition, allelopathy, and responses to environmental events （e.g., insect plagues and extreme weather）. However, current approaches to analyzing interspecific associations have the following limitations ： （ 1 ） measurement-based results are greatly influenced by the size and number of the plots used ; （2） these methods can only be used to measure the relationship between two species in a community; and （3） interspecific association analyses describe the external correlations between species and reveal either the results of interspecific competition or the current state of the community, but not the processes that drive these patterns. Therefore, further research is needed to address these issues. First, niche theory could be used to study an interspecific association and reveal the correlation between two species. Second, changes in interspecific association caused by density could be studied, and the relationship between habitat heterogeneity and interspecific association analyzed. Third, the physiology and molecular genetics of interspecific association could be studied to explore the mechanisms by which these associations are formed. This review emphasizes that multi-scale ordination could be used to analyze complicated interspecific associations at different patterns of scale, for plant facilitation and invasion in particular. In such an analysis, the Fisher exact test combined with the Pearson correlation and Spearman rank correlation coefficients could be used to investigate variations in interspecific associations dominated by density due to plant physiology, molecular genetics, or ecological niche. This approach could more accurately and reliably reveal the dynamics of interspecific associations between plant species.