Altered litter stoichiometry drives energy dynamics of food webs through changing multiple facets of soil biodiversity

Global change in organismal stoichiometry and biodiversity is often correlated with energy dynamics in ecological networks that underpin the functioning of terrestrial ecosystems and services. However, we know little about which facets of biodiversity, such as taxonomic, functional, and phylogenetic diversity, account for most of the variation in the energy dynamics of ecological networks along litter stoichiometry gradients. Here, we quantified how multiple facets of biodiversity impact energy fluxes of soil food webs through time in agricultural fields incorporating litter from six plant species of varying C:N stoichiometry. We found that community biomass and energy flux in soil food webs decreased while community maintenance cost (i.e. energy flux to biomass ratio) increased with increasing litter C:N ratio. Taxonomic, functional, and phylogenetic diversity of soil nematodes declined along increasing litter C:N stoichiometry, and together explained 73 % and 51.3 % of variation in community biomass, 71.6 % and 49.2 % of variation in energy flux, and 59.8 % and 37.4 % of variation in community maintenance cost in early and later decomposition stages, respectively. Functional and taxonomic diversity were highly associated with energy dynamics in early decomposition stages, while phylogenetic diversity emerged as the central predictor in later decomposition stages. By identifying the crucial role of multi-faceted biodiversity conservation facilitated by low C:N litter in driving the energy dynamics of food webs, these findings shed new light on the applicability of energy dynamics for linking biodiversity and ecosystem functioning under global change scenarios.