Comparing clades: Using a trait-based approach to measure functional diversity of forest trees and soil microbes across the Latitude Biodiversity Gradient
Results/Conclusions Our results enable one of the first comparison of functional diversity within and across microbial and plant species communities across latitude. In contrast to recent studies that have shown that climate only has a relative weak signal in patterns of single trait shifts across climate gradients, we show that when differences in species abundances are taken into account that multivariate shifts in trait composition is largely explained by climate (~ 30 – 93%). We find that soil temperature and mean annual temperate have the strongest effect in shifts in community trait diversity. Overall, our results suggest that observed shifts in taxonomic diversity across latitude are associated with shifts in the functional composition in plant and soil bacterial communities but less so with fungal composition. This is consistent with hypotheses that suggest richness gradients are significantly structured due to traits/function. While we highlight several challenges that remain in fully comparing patterns of diversity across differing taxonomic groups, nevertheless, our findings have important implications for assessing biodiversity theory and for the main drivers that structure diversity gradients.