Global biogeography of the biodiversity-productivity relationship in forests

The biodiversity-productivity relationship (BPR) is central to our understanding of ecosystem functioning and restoration practices. Quantifying variation in the BPR across environmental gradients is thus critical for a spatially-explicit understanding of this key ecosystem property. Here, by integrating plot-level tree occurrence information from the Global Forest Biodiversity initiative (GFBi), satellite-derived net primary productivity, and environmental covariates, we estimated global variation in the BPR of forests along spatial and environmental gradients. The results show that variation in the forest BPR correlates with temperature and water availability, leading to significant differences in the forest BPR across biomes: the highest positive BPR occurs in arid and boreal forests, the lowest BPR in temperate broadleaved and mixed forests. In addition, forest age played a key role in mediating the BPR, with no BPR found in young forests (<100 years) and an increasingly positive BPR found in older forests. By quantifying the main drivers of global variation in the forest BPR, our study aids to a better understanding of forest ecosystem functioning and carbon storage and the global consequences of biodiversity loss.