Comparing the relative effects of species and size structure on forest productivity in different local environments

摘要

Understanding diversity-productivity relationships (DPRs) is of theoretical importance and has practical implications for biodiversity conservation and forest management. Although the effects of species diversity and structural diversity on productivity have been a focus of intense research, the relative importance of these effects in different environments remains poorly understood. Based on three extensive datasets obtained from northeastern China, we examine how the species-diversity-productivity and structural-diversity-productivity relationships change with local conditions, and we compare the relative importance of these diversity effects on productivity in the different environments. Our results show that: (1) Positive relationships exist between species diversity and productivity in the overall structural equation model as well as the specific ones for each forest separately. Structural diversity only had a significant effect on productivity in the homogeneous environment of forest 1. (2) Species diversity showed stronger and more consistent effects on productivity than structural diversity. The relationship between structural diversity and productivity was more constrained by local environmental condition.