Global meta‐analysis of litter addition effects on plant performance and ecosystem functions

Plant litter is a critical component of terrestrial ecosystems, yet its effects on plant performance and ecosystem functioning at the global scale remain poorly understood.

Our global meta‐analysis (1802 comparisons, 156 studies) of litter addition studies revealed significant heterogeneity in effects across organizational levels (populations, communities and ecosystems).

Notably, litter quantity emerged as the primary driver of these outcomes, outweighing the influence of climatic factors. For example, litter addition reduced plant growth by 12.57% and survival by 31.48% at the population level, with these effects exacerbated at higher litter quantities, regardless of climatic conditions. Conversely, litter addition positively influenced the soil carbon and nitrogen content at the ecosystem level.

Synthesis . Our findings demonstrate how litter addition affects diverse population‐, community‐ and ecosystem‐level processes, while underscoring the importance of litter quantity in mediating these effects. Inclusion of litter quantity data will therefore be crucial for the accurate prediction of population dynamics and biogeochemical cycles under climate change.