Ecosystem functioning and stability are mainly driven by stand structural attributes and biodiversity, respectively, in a tropical forest in Southwestern China

Abstract

In natural forests, it is increasingly suggested that stand structural attributes are more important for community-scale biomass and productivity than biodiversity, while for their stability, the relative importance of stand structural attributes vs. diversity still remains unclear. Based on a dataset from 10 sites investiagted annually from 2004 to 2010 in tropical forest in Southwestern China, we used mixed-effect model and variation partitioning to test the relative importance of stand structural attributes vs. biodiversity on biomass, productivity and their stability. We found that stand structural attributes are dominant predictors for forest biomass and productivity, while diversity is predominant in affecting biomass and productivity stability at all grain sizes (0.04 hm2~0.12 hm2). Moreover, functional diversity seemed to be more important for biomass, productivity and their stability than taxonomic and phylogenetic diversity, and richness was more important than the other two diversity components (evenness and divergence). Our results reconcile the recent debate on the relative importance of diversity vs. stand factors on ecosystem properties, and suggest that forest management to adjust stand structure is an effective way to increase forest carbon storage rapidly, but biodiversity conservation may be crucial for ecosystem stability under climate change.