Complex interactions between ecosystem productivity and herbivore diets lead to non-predicted effects on nutrient cycling

The study of Ibanez et al. deals with the effect of herbivores on soil functioning in relation to primary production and herbivore diet. It is a complex experiment, given the number of compartments (plants, herbivores, decomposers) and the processes (primary production, diet differences, decomposition of organic matter) that are considered. The experimental design is fine, statistical analyses also, the conceptual background is well exposed and the paper is well written. It misses some coherence between the collected data and the tested conceptual framework.