Stoichiometry of litter decomposition under the effects of climate change and nutrient enrichment: A meta-analysis

The cycling of nutrients from plant litter has key implications for the functioning of terrestrial ecosystems by controlling nutrient availability and net primary production. Despite extensive research on the effects of global change on ecosystem functioning, the direct implications of global change on stoichiometry and nutrient dynamics during litter decomposition remain poorly understood. To address this gap, we conducted a meta-analysis.

We analysed 178 experiments that simulated (i) warming, (ii) drought, (iii) increased water availability, (iv) N enrichment, (v) P enrichment, and (vi) combined N and P (N + P) enrichment. We compared earlier (approximately six months) and later (approximately one year) stages of decomposition and analysed the specific effects taking into account climate and plant type.

The C:N and C:P ratios decreased in most warming and nutrient enrichment scenarios, leading to losses of litter C content, while the N:P ratio remained more resilient and affected by water availability. Furthermore, the abundance of resources (water and N + P) fosters the decomposition of litter. The nutrient mobilisation increases for both P and N under non-limited nutrient enrichment and it is faster for N than for P when water increases its availability. Nutrient enrichment was relevant in later stages of decomposition.

Our study provides insights into the fate of litter decomposition and its stoichiometric dynamics in response to drivers of global change. Concerning scenarios of C release and N and P immobilisation were identified. However, further experimentation and analysis are necessary to consider all interacting drivers.