Leaf litter, as a multifunctional legacy of plants, plays essential role in driving biogeochemical cycles, while simultaneously providing crucial habitat and food resources for soil organisms. Litter traits and soil fauna play crucial roles in determining litter decomposition. However, it is still unknown to what extent do soil fauna contribute to litter decomposability. Nor do the leaf size and defensive traits when compared to economics traits.

Researchers from Functional Ecology Group of Wuhan Botanical Garden, collaborating with researchers from Northwest Institute of Plateau Biology, Chinese Academy of Sciences, conducted a meta-analysis to synthesize existing research findings regarding the effects of leaf traits and soil fauna on litter decomposability on a global scale.

The findings demonstrated that soil fauna significantly accelerated the decomposition rate across diverse climate zones (e.g., tropical, subtropical, temperate, and alpine climate zones), ecosystems (e.g., forest, grassland, wetland, and farmland), and litter types (e.g., evergreen woody plants, deciduous woody plants, annual herbs, and perennial herbs). The combined influence of climate factors (mean annual temperature and precipitation) and litter quality served as a robust predictor of the contribution of soil fauna to litter decomposability across different biomes.

The leaf size traits (leaf length, width and area) positively modulated the effect of soil fauna on litter decomposition, whereas the defensive traits (cellulose, hemicellulose, total phenols, and the concentration of condensed tannins) were negatively correlated. As for economic traits, specific leaf area and phosphorus concentration had a positive correlation with the response ration of fauna in modulating litter decomposition, whereas carbon and nitrogen had no significant correlation.

This study emphasizes the crucial role of soil fauna and litter quality to leaf litter decomposition, suggesting that leaf size and defensive traits play important roles in modulating the effects of soil fauna on litter decomposition.

This work was supported by the Knowledge Innovation Program of Wuhan-Basic Research and China Scholarship Council. This research entitled "Effects of leaf size and defensive traits on the contribution of soil fauna to litter decomposition” was published in Forests.

Mean effect size of soil fauna presence on litter mass loss at global scale (Image by Dr. WANG)