Unravelling biodiversity–productivity relationships across a large temperate forest region

Abstract Biodiversity–productivity relationship (BPR) has become a central issue of ecology and conservation biology. The current understanding of BPR mainly comes from local scales, which is, however, difficult to extend to the BPR pattern at the regional scale owing to the scale dependence of regional communities. To elucidate the BPR at the regional communities across multiple spatial scales, we investigated the 328 plots with about 30,000 trees across 700,000 km 2 regional area in the temperate forests. In this study, the n closest plots were aggregated to form regional clusters representing the spatial scale characterized by the spatial extent of regional communities, which were used to explore the relationships of multiple facets of biodiversity (i.e. taxonomic, functional, and phylogenetic diversity) with the productivity of regional communities. Our study provides insight into the discrepancy among taxonomic, functional, phylogenetic biodiversity in modulating productivity across the different specific biogeographical clusters within a large regional area. We found that the spatial extent of the tree community could change the importance of the multiple facets of biodiversity on productivity. Phylogenetic diversity may be a better driver of productivity at the smaller spatial scale of the regional communities. In contrast, taxonomic diversity appears to be more predominant in affecting productivity at the broader spatial scale. Our results suggest that the understanding of the BPR patterns benefited from the multiple facets of biodiversity. The findings highlight the scale dependence of the BPRs, representing the significance of the spatial extent of the regional communities on them. This would improve our abilities to interpret and predict temperate forest productivity across the different spatial scales of the regional communities. A free Plain Language Summary can be found within the Supporting Information of this article.