Short‐term nitrogen enrichment seasonally attenuates the positive relationship between tree species richness and litterfall production

Résumé fourni par la source

Abstract Global forest ecosystems are experiencing progressive declines in plant species diversity while being increasingly exposed to atmospheric nitrogen (N) deposition. Although increased tree diversity has been shown to enhance litterfall production, how N enrichment modifies biodiversity effects on forest litterfall production remains unclear. This study employed a full‐factorial experimental design manipulating tree species richness (1, 4, 8 and 16 species) and N addition (ambient vs. addition of 50 kg N ha −1 year −1 ) to examine how N enrichment modulates the relationship between biodiversity and litterfall production in a subtropical experimental forest. Our findings indicate a significant positive relationship between tree species richness and litterfall production. Specifically, the positive effect of tree species richness on litterfall production tends to be stronger in the winter. Additionally, a significant interaction between tree species richness and N enrichment was detected in the winter, suggesting that short‐term N enrichment seasonally attenuates the positive relationship between tree species richness and litterfall production. Furthermore, short‐term N enrichment seasonally modified the mechanistic basis of litterfall production by disrupting the linkages associated with the community‐weighted mean of fast–slow leaf traits and edaphic conditions. Synthesis . These results suggest that N enrichment seasonally diminishes the positive influence of tree species diversity on litterfall production, highlighting the importance of seasonal dynamics in biodiversity–ecosystem functioning relationships under global change.

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