Effects Of Functional Diversity On Productivity In A Typical Mixed Broadleaved-Korean Pine Forest

In the context of global environmental change and biodiversity loss,the relationship between biodiversity and ecosystem function has become a research hotspot.Productivity,as one of the important ecosystem functions,has attracted much attention.A better understanding of patterns and drivers of forest-based productivity contributes to the development of climate change mitigation strategies and the prediction of the consequences of biodiversity loss from anthropogenic activities.There are two hypotheses about the mechanism of plant diversity affecting ecosystem function,one is based on biomass ratio hypothesis of dominant species in community,the other is niche complementary hypothesis.Although it is generally believed that the two hypotheses are not mutually exclusive,the relative importance of the two hypotheses remains controversial.therefore,it is of great significance to explore which hypothesis is more universal,or the applicable conditions of two kinds of functional diversity indicators to indicate the variation of productivity.As a multivariate statistical method to test the suitability of a certain theory or hypothesis,the structural equation model(sem)integrates factor analysis and path analysis with factor analysis and clearly gives the strength of each relationship.This study compared the relative importance of biomass ratio hypothesis and niche complementation hypothesis in explaining productivity variation based on a 9 hm2 mixed broadleaved-Korean pine forest dynamics plot in Xiaoxinganling to explore whether the relationship between biodiversity and productivity was affected by biological and abiotic factors.To this end,8 functional traits of 41 species were collected and measured.By calculating the community initial biomass,species diversity,functional diversity,community weighted average values and environmental factors of plant traits,the correlation of species diversity and productivity were compared by using linear regression model,structural equation model.The results showed that both species diversity and functional diversity had significant effect on productivity.According to the linear regression model of diversity and productivity,functional diversity was more closely related to productivity than species diversity,indicating that niche complementarity hypothesis is more suitable for explaining the variation of productivity in broadleaved-Korean pine forest community.The relationship between biodiversity and productivity is influenced by the combination of biotic and abiotic factors.Compared with the composition of diversity and functional traits(vegetation quality),the initial biomass(vegetation quantity)can explain the variation of productivity more effectively.The study of the relationship between biodiversity and productivity should proceed from the same time of vegetation quality and vegetation quantity,evaluate the multiple abiotic and biotic drivers of ecosystem processes,while maintaining forest functional diversity and enhancing the protection of plant and soil environment is of great significance to effectively increase productivity and maintain biodiversity.