Abstract:

Aims: Biodiversity serves as a critical foundation for the formation and maintenance of ecosystem functions. Its influence on ecosystem functioning changes dynamically during forest succession. However, the relative contributions of multi-dimensional biodiversity (species, traits, phylogeny) and their variations across forest successional stages remain unclear. This study aims to investigate the impacts of multi-dimensional biodiversity on forest productivity and their variations across forest succession. 

Methods: This study explored the biodiversity and productivity relationships of forests at different successional stages in Changbai Mountains, based on the observations from three 5.2-ha forest dynamics plots in secondary poplar-birch forest (early succession stage), secondary conifer-broadleaf mixed forest (middle succession stage), and primary Korean pine-broadleaf forest (late succession stage). Vegetation survey data were used to calculate species diversity, functional diversity, and phylogenetic diversity. Aboveground biomass and forest productivity were employed as ecosystem function indicators. Structural equation modeling was applied to disentangle the impacts of multi-dimensional biodiversity on ecosystem functions and their variations across successional stages. 

Results: (1) With forest succession, aboveground biomass increased continuously while productivity decreased. (2) The relationship between biodiversity and biomass and productivity changes with forest succession, generally showing a weakening trend across stages. (3) Compared with functional diversity and phylogenetic diversity, species diversity does not significantly affect ecosystem functions. (4) Abiotic factors dynamically regulated resources during succession and productivity. 

Conclusion: This study enhances the understanding of dynamic patterns and ecological mechanisms underlying multi-dimensional biodiversity and ecosystem function relationships during forest succession, providing scientific insights for the ecological restoration and sustainable management of secondary forests in northeastern China.

Key words: species richness, functional diversity, phylogenetic diversity, above-ground biomass, forest productivity, forest succession