Résumé
Soils are recognized as one of the greatest biodiversity reservoirs of the planet, as communities of edaphic animals include an outstanding diversity of body sizes, life forms and behaviours, with representatives of virtually all the major taxa and trophic groups that form the terrestrial animal kingdom. Paradoxically, soils are also among the most poorly studied habitats of our planet, and we most likely only know an infinitesimal part of the global taxonomic and functional diversity of its biota. In this paper, we provide a 'state-of-the-art' review and reveal the main gaps in our knowledge of soil animal diversity, its function and how it contributes to the provision of important ecosystem services. We also propose some further research priorities for improving our knowledge of soil fauna and contributing to a better conservation of their communities.