卧龙自然保护区三江珙桐群落种间关系的数量分析

Numerical analysis on interspecific relationships in Davidia involucrata community in Sanjiang Wolong Nature Reserve

应用2×2列联表的Fisher精确检验、Pearson相关系数和Spearman秩相关系数检验研究了卧龙自然保护区三江珙桐(Davidia involucrata)群落种间关系。测定了83种植物,共3 403个种对的种间关联(或相关)。结果表明,2×2列联表的Fisher精确检验共186个种对为正关联,100个种对为负关联(P<0.05或P<0.01);Pearson相关系数有295个种对为正关联,129个种对为负关联;Spearman秩相关系数有448个种对为正关联,244个种对为负关联。用2×2列联表的Fisher精确检验不能反映两个种对的数量关系,应用Pearson相关系数和Spearman秩相关系数刻化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。种对的正关联和正相关,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。

Employing Fisher＇s precise test for 2 × 2 contingency table, Pearson＇s correlation coefficient and Spearman＇s rank correlation coefficient, this paper studied the 3 403 species-pairs＇ interspecific relationships of 83 species in D. involucrata community in Sanjiang Wolong Nature Reserve. The results showed that through Fisher＇s precise test for 2 × 2 contingency table, the positive association coefficients of 186 species-pairs were either significant（P 〈0.05） or highly significant （P 〈0.01）, and the negative association coefficients of other 100 species-pairs were significant or highly significant. The positive correlation coefficients of 295 and 448 speciespairs were significant or highly significant by using Pearson＇s correlation coefficient and Spearman＇s rank correlation coefficient, respectively, while 129 and 244 species-pairs had significant or highly significant negative correlation coefficients by using the same tests. Because Fisher＇s precise test for 2 × 2 contingency table could not numerically reflect the contrasting correlation between species, Pearson＇s correlation coefficient and Spearman＇ s rank correlation coefficient were applied to test the interspecific relationships. Compared with Pearson＇ s correlation coefficient, Spearman＇ s rank correlation coefficient test was more sensitive. Positive association and correlation between species occurred where the members of species-pairs had similar biological characteristics or traits, which made them ecologically adaptive for similar habitats but with segregated niches, while negative association and correlation between species occurred where species had different biological features, which made them differently adaptive for habitats or with overlapping niches.