Summary Some temperate tree species are associated with very low soil nitrification rates, with important implications for forest N dynamics, presumably due to their potential for biological nitrification inhibition (BNI). However, evidence for BNI in forest ecosystems is scarce so far and the nitrifier groups controlled by BNI‐tree species have not been identified. Here, we evaluated how some tree species can control soil nit...

Summary Nitrogen ( N ) is considered as a main limiting factor in plant growth, and nitrogen losses through denitrification can be responsible for severe decreases in plant productivity. Recently, it was demonstrated that F allopia spp. is responsible for biological denitrification inhibition ( BDI ) through the release of unknown secondary metabolites. Here, we investigate the secondary metabolites involved in the BDI of F al...

The roles of species richness, resource use, and resource availability are central to many hypotheses explaining the diversity–invasion phenomenon but are generally not investigated together. Here, we created a large diversity gradient of soil microbial communities by either assembling communities of pure bacterial strains or removing the diversity of a natural soil. Using data on the resource‐use capacities of the soil commun...

It has long been recognized that plant species and soil microorganisms are tightly linked, but understanding how different species vary in their effects on soil is currently limited. In this study, we identified those plant characteristics (identity, specific functional traits, or resource acquisition strategy) that were the best predictors of nitrification and denitrification processes. Ten plant populations representing eigh...

Emissions of the trace gas nitrous oxide ( N 2 O ) play an important role for the greenhouse effect and stratospheric ozone depletion, but the impacts of climate change on N 2 O fluxes and the underlying microbial drivers remain unclear. The aim of this study was to determine the effects of sustained climate change on field N 2 O fluxes and associated microbial enzymatic activities, microbial population abundance and community...

Predicting biodiversity effects on ecosystem functioning requires adequate evaluation of the mechanisms explaining why more diverse systems could perform better than less diverse ones. In this context, tackling functional diversity has become an important issue. Even though the aggregation of species into functional groups supposes niche differences among groups, the concept of niche has not been fully exploited in the context...

Summary Analysing the consequences of the decrease in biodiversity for ecosystem functioning and stability has been a major concern in ecology. However, the impact of decline in soil microbial diversity on ecosystem sustainability remains largely unknown. This has been assessed for decomposition, which is insured by a large proportion of the soil microbial community, but not for more specialized and less diverse microbial grou...

Summary The paradigm that soil microbial communities, being very diverse, have high functional redundancy levels, so that erosion of microbial diversity is less important for ecosystem functioning than erosion of plant or animal diversity, is often taken for granted. However, this has only been demonstrated for decomposition/respiration functions, performed by a large proportion of the total microbial community, but not for sp...

Summary Management by combined grazing and mowing events is commonly used in grasslands, which influences the activity and composition of soil bacterial communities. Whether observed effects are mediated by management‐induced disturbances, or indirectly by changes in the identity of major plant species, is still unknown. To address this issue, we quantified substrate‐induced respiration (SIR), and the nitrification, denitrific...

Summary Nickel mine spoils in New Caledonia represent an extreme environment, rich in nickel and strongly deficient in elementary elements such as carbon and nitrogen. To rehabilitate these sites, revegetation attempts are performed with endemic plant species establishing dinitrogen‐fixation symbiosis ( Gymnostoma webbianum and Serianthes calycina ). As this biological fixation process provides the major source of available ni...