Ecosystem scale trade-off in nitrogen acquisition pathways.

The nitrogen (N) cycle in terrestrial ecosystems is strongly influenced by resorption before litter fall and by mineralization after litter fall. Although both resorption and mineralization make N available to plants and are influenced by climate, their linkage in a changing environment remains largely unknown. Here, our synthesis study shows that, at the global scale, increasing N-resorption efficiency negatively affects the N-mineralization rate. As temperature and precipitation increase, the increasing rates of N cycling closely correspond to a shift from the more conservative resorption pathway to the mineralization pathway. Furthermore, ecosystems with faster N-cycle rates support plant species that have higher foliar N:P ratios and microbial communities with lower fungi:bacteria ratios. Our study shows an ecosystem scale trade-off in N-acquisition pathways. We propose that incorporating the dynamic interaction between N resorption and N mineralization into Earth system models will improve the simulation of nutrient constraints on ecosystem productivity.