Interactions between C:N:P stoichiometry and soil macrofauna control dung decomposition of savanna herbivores

1. Although dung of mammalian herbivores is an important pathway for nutrient return in savanna ecosystems, differences in dung decomposition rates among species have been little studied. 2. We measured rates of dung deposition and decomposition for various herbivores in a moist Tanzanian savanna, and related differences among species to nutrient concentrations and the activities of soil macrofauna (e.g., different mesh sizes of decomposition bags, or presence and absence of dung beetles). 3. Dung C:N:P stoichiometry varied widely among species, which could in part be explained by differences in feeding strategy (browsers vs. grazers) and digestive physiology (ruminants vs. non-ruminants). Rates of both decomposition and nutrient release were influenced by the C:N:P stoichiometry of dung, with lower relative losses of the least abundant nutrient. Surprisingly, soil macrofauna increased relative losses of the least abundant nutrient, thereby stabilizing the ratio of N loss to P loss. Dun...