山西翅果油树群落种间关系的数量分析

NUMERICAL ANALYSIS OF INTERSPECIFIC RELATIONSHIPS IN AN ELAEAGNUS MOLLIS COMMUNITY IN SHANXI

应用 2× 2列联表的 Fisher精确检验、Pearson相关系数和 Spearm an秩相关系数检验研究了山西翅果油树群落的种间关系 ,分别测定了 42种植物 ,共 86 1个种对的种间关联 (或相关 )。结果表明 :1) 2× 2列联表的精确检验共有 2 8个种对为正关联 ,14个种对为负关联 (p <0 .0 5或 p<0 .0 1,下同 ) ;Peaorson相关系数有 5 6个种对为正相关 ,14个种对为负相关 ;Spearman秩相关系数有 96个种对呈正相关 ,46个种对呈负相关。 2 ) 2× 2列联表的Fisher精确检验不能反映两个种对间的数量变化关系 ,应用 Pearson相关系数和 Spearman秩相关检验来刻划种对间的数量变化关系 ;与 Pearson相关系数检验相比 ,Spearman秩相关系数检验具有较高的灵敏度。 3)种对间的正关联和正相关 ,主要是由于它们具有相近的生物学特性 ,对生境具有相似的生态适应性和相互分离的生态位所致 ;而种对间的负关联和负相关 ,则主要是由于它们具有不同的生物学特性 ,对生境具有不同的生态适应性和相互重叠的生态位所致。

Interspecific relationships in Elaeagnus mollis communities in Shanxi were studied using Fisher's exact test for a 2×2 contingency table, Pearson's correlation coefficient and Spearman's rank correlation coefficient. The results indicated that:1) Positive association coefficients of 28 species pairs for the exact test were either significant ( p <0.05) or highly significant ( p <0.01) and negative association coefficients were significant or highly significant in 14 other species pairs. In addition, positive correlation coefficients of 56 and 96 species pairs were significant or very significant using the Pearson's correlation coefficient and Spearman's rank correlation coefficient respectively while 14 and 46 species pairs had significant or very significant negative correlation coefficients using these same tests. 2) Because Fisher's exact test for 2×2 contingency table can not reflect numerically contrasting interspecific relationships, Pearson's correlation coefficient and Spearman's rank correlation coefficient were applied to test for correlation between species. Moreover, compared with Pearson's correlation coefficient, Spearman's rank correlation coefficient test was more sensitive. 3) Positive association and correlation between species occur where members of a species pair have similar biological characteristics or traits that make them ecologically adaptive for similar habitats but have segregated niches. Negative association and correlation between species occur where species have different biological features that are differently adaptive for habitats or have overlapping niches.