Abstract Biodiversity is a key driver of ecosystem functioning, largely due to niche complementarity among species. Litter decomposition plays a crucial role in the cycling of matter, which supports other processes such as soil formation, primary productivity, and carbon storage. We examined whether litter mixtures with higher taxonomic diversity decompose more rapidly than those with lower diversity, and to what extent arthropods contribute to this pattern. We established a natural microcosm experiment within a remnant of Atlantic rainforest in Southeastern Brazil, where we set litterbags of equal weight (10 g), but varying numbers of litter species (from one to 16). Species identities were randomly assigned across replicates to control for species-specific effects. The litterbags remained in the field for 189 days, after which we extracted arthropods using Berlese funnels operated continuously for seven days. Richer litter mixtures decomposed faster and supported a higher abundance of arthropods. Previous studies reported varied results, which depended on specific species in the mixture and synergistic or antagonistic effects. Such variability is often attributed to site-specific conditions, experimental design, and the identity of litter species used. Importantly, our experimental design minimised the influence of particularly responsive species in high-diversity treatments while preserving natural field conditions. Higher abundance of arthropods in richer mixtures likely played a central role in accelerating decomposition. Soil fauna typically enhances decomposition through physical fragmentation, which increases surface area and alters structural properties of the litter. This mechanical disruption facilitates microbial colonisation and mineralisation by fungi and bacteria, thereby promoting more efficient decomposition.
Sobrinho et al. (Thu,) studied this question.