Nematodes are key components of soil biodiversity and represent valuable bio-indicators of soil food webs. Numerous community indices have been developed in order to track variations in soil ecosystem processes, but their use is mainly restricted to anthropogenic stresses. In this study, we propose to expand the use of nematode' derived ecological indices in order to shed light on soil ecosystem functioning along elevation gradients. For this purpose, we aimed at determining how elevation affects the abundance, the composition and the functional diversity of nematode communities. To understand the underlying ecological parameters driving these patterns we studied both abiotic factors (soil properties) and biotic factors (trophic links, relationships with plant diversity). Our results indicate that (1) nematode abundance increases with elevation, from lowland forests to alpine meadows; (2) differences in nematodes communities rely on habitat-specific functional diversity (e.g. local adaptations, "colonizer/persister" status) while most trophic groups are ubiquitous; and (3) variations in the metabolic footprint of the complete nematode community suggest that their contribution to soil ecosystem processes generally increases with elevation. The resulting cascading effects on the soil food web structure are discussed from an ecosystem functioning perspective. Overall, this study is in line with the literature highlighting the importance of nematodes in soil ecosystems and brings insights in their enhanced role at high elevation.