Objective Thoroughly exploring the relationship between species and structural diversity and productivity is an important prerequisite for the improvement of both forest biodiversity and productivity, and is of great significance for forest scientific management. In this study, three typical forest communities in Changbai Mountains of northeastern China were selected as the research object to analyze the relationship between species and structural diversity and productivity in different succession stages. The early, middle and late stages of communities were represented by the secondary poplar-birch forest, coniferous-broadleaved mixed forest and broadleaved Korean pine forest.
Method Multiple regression models were built for the comparison of the correlations between different diversity indices and productivity, based on the regression results, the best index was determined to represent for species and structural diversity, and then the structural equation model was built to compare the relative importance of species and structural diversity on productivity.
Result In the early succession stage, the relationship between species richness, DBH evenness and productivity was the most significant and the effects of these two diversity indices on productivity were similar but not strong. In the middle succession stage, the relationship between species richness, DBH Shannon index and productivity was the most significant, they both had positive effects on productivity, and the effects of species diversity on productivity was stronger than that of structural diversity. In the late stage of succession, there was no significant correlation between species diversity as well as structural diversity and productivity.
Conclusion The relationship between species diversity as well as structural diversity and productivity of Changbai Mountains natural forest community is related to the succession stage, and the niche complementary effect is significant in the middle succession stage. Species diversity and structure optimization can improve community productivity.