Responses of invertebrate traits to litter chemistry accelerate decomposition under nitrogen enrichment

Nitrogen (N) enrichment shapes litter chemistry, subsequently influencing soil invertebrates and litter decomposition. However, there has been a lack of attention to how soil invertebrates respond to changes in litter chemistry and then drive litter decomposition under N enrichment. Here, trait-based approaches were adopted to explore functional responses of Collembola, a crucial and functional group of invertebrates. We conducted reciprocal transplantation of plant litter between ambient N levels (0 kg N ha⁻¹ yr⁻¹) and N enrichment (90 kg N ha⁻¹ yr⁻¹) plots in a field experiment, quantifying Collembola traits and litter mass loss during litter decomposition process. Results showed that N enrichment-derived litter recruited Collembola with long antenna, legs, and strong mandibles in enrichment environment, while Collembola with same traits were recruited by ambient-derived litter in ambient environment. Collembola traits, including antenna to body ratio, leg to body ratio, and mandible width to length ratio, coincided with high litter decomposition rates under N enrichment. Overall, the results provide evidence that Collembola with strong resource acquisition abilities responded to changes in litter chemistry, and such shifts further accelerate litter decomposition under N enrichment. Our findings demonstrate that adopting trait-based approaches to link litter and invertebrates would advance the understanding of ecosystem processes governed by biological regulation under global change.