广西大石围天坑群天坑森林主要木本植物种间关联性研究 postprint

Abstract: For understanding the interspecific associations of main woody plant in tiankeng forests, we choose 7 typical tiankeng forests as researched area and established a total of 18 sample plots in Dashiwei Tiankeng Group. We selected woody plants with importance values >1 as the study object, and quantitatively analyzed interspecific associations and correlations by a set of methods, namely, variance ratio, χ2 test, Pearson correlation coefficient test, Spearman rank correlation coefficient test and principal component analysis ( PCA ). The results were as follows: (1)Overall interspecific association were significant positive correlations in tree layer, non-significant, positive associations in shrub layer and significant, positive associations in community, indicating that the plant community in tiankeng forests was at a stable stage. (2)The χ2 test, Pearson correlation coefficient test and Spearman rank correlation coefficient test found that there was a difference between positive and negative correlation in tree layer and shrub layer. Many positive correlation species pairs existed in tree layer and many negative correlation species pairs existed in shrub layer, but both of them were more significantly correlation species pairs than non-significantly ones. Thus, the stability of community composition in tree layer was higher than shrub layer. And, there was a strong competition and cooperation between species pairs in tree layer, a strong competition and repulsion between species pairs in shrub layer, and a close interspecific association in community. (3)According to the results of PCA, the 24 main woody species were divided into four ecological species groups. The tiankeng forests community distribution was in a circle distribution pattern from the bottom to the top of the tiankeng topography, which was affected by environmental differences and species characteristics. In conclusion, these results suggest that the close interspecific association may be one of the maintenance mechanisms of tiankeng forest species diversity, while the self-regulation of interspecific association within the community and convergence adaptation of species to habitat heterogeneity are the basis for maintaining the stability of the community.