Climate dependence of the macrofaunal effect on litter decomposition-A global meta-regression analysis.

Litter decomposition by microorganisms and animals is influenced by climate and has been found to be higher in warm and wet than in cold and dry biomes. We, however, hypothesized that the macrofaunal effect on decomposition should increase with temperature and aridity since larger animals are more tolerant to aridity than smaller organisms. This hypothesis was supported by our global analysis of macrofauna exclusion studies. Macrofauna increased litter mass loss on average by 40%, twofold higher than the highest previous estimation of macrofaunal effect on decomposition. The strongest effect was found in subtropical deserts where faunal decomposition had not been considered important. Our results highlight the need to consider animal size when exploring climate dependence of faunal decomposition, and the disproportionately large role of macrofauna in regulating litter decomposition in warm drylands. This new realization is critical for understanding element cycling in the face of global warming and aridification.