Global Patterns of Leaf Litter C:N:P Stoichiometry Under Current and Future Climate Scenarios

Plant litter carbon (C), nitrogen (N), and phosphorus (P) stoichiometry can indicate ecosystem nutrient use efficiency and limitation. Yet, a comprehensive quantification of plant litter C:N:P ratios at the global scale remains elusive, limiting our understanding of how their variation responds to future climate change. We constructed a database comprising 11,807 records of leaf litter C:N:P ratios, quantifying their global patterns under current and future (2041–2100) climate scenarios using the random forest method. We found that global mean leaf litter C:N, C:P and N:P ratios were 46.5, 669.4 and 16, respectively, while they were dependent on mycorrhizal association, taxonomic division, and/or plant functional type. Leaf litter C:N and N:P ratios showed opposite latitudinal patterns, being larger in high and low latitude regions, respectively, while the C:P ratio remained relatively stable in low latitude regions but increased significantly toward the poles. Our simulations further revealed that increasing climate warming decreased the leaf litter C:N ratio but increased the C:P and N:P ratios in terrestrial plants, despite the fact that their variations were largely dependent on ecosystem type. These findings clearly benefit us to understand the role of leaf litter in regulating the cycling of C and nutrients, responding to ecosystem plant development with climate change.