Numerical Analysis on Interspecific Relationships in Taxus chinese var. mairei Communities,Shanxi

Interspecific relationships in Taxus chinese var.mairei communities in Shanxi were studied by using variance ratio,χ2 test for 2×2 contingency table,Pearson's correlation coefficient and Spearman's rank correlation coefficient.The results indicated that:(1)The overall association of the community was significant(P0.05).(2) The positive association coefficients of 87 species-pairs for the exact test were either significant(P0.05) or high significant(P0.01) and the negative association coefficients were significant or highly significant in other 18 species-pairs.In addition,the positive correlation coefficients of 59 and 95 species-pairs were significant(P0.05)or high significant(P0.01) by using the Pearson's correlation coefficient and Spearman's rank correlation coefficient respectively while 29 and 62 species-pairs had significant(P0.05)or high significant(P0.01),and the negative correlation coefficients using these same tests.(3)Because χ2 test for 2×2 contingency table can not reflect exactly interspecific relationships,Pearson's correlation coefficient and Spearman's rank correlation coefficient were used to test for correlation between species.Moreover,compared with Pearson's correlation coefficient,Spearman's rank correlation coefficient test was more sensitive.(4)The species with similar biological features tended to be positively associated and correlated,while those with different biological features and different adaptabilities to the habitats or existing inter competitions tended to be negatively associated and correlated.