Résumé
Soils in urban parks are mainly manmade and called Technosols. These Technosols are made of backfill with or without a topsoil addition, which may affect both the physicochemical properties of these soils and the success of soil fauna colonization. The effects of these initial soil management conditions on colonization dynamics of Technosols have not been evaluated yet.To fill this gap, we sampled earthworms and ants in 20 Technosols covered by lawn and located in urban parks around Paris (France). We selected Technosols constructed with or without an initial addition of topsoil and distributed along an age gradient since construction ranging from 2 to 64 years. Surrounding greening index around Technosols, management practices and physicochemical soil properties have also been recorded.Surprisingly, no significant differences were observed in the physicochemical properties of Technosols regardless of the absence/presence of topsoil. Communities were composed of few ubiquitous species, which could explain the lack of species richness response to any of our variables. Earthworm and ant abundances increased significantly along the age gradient only in Technosols with initial addition of topsoil. In Technosols, initial conditions apparently determine in part soil macrofauna.Thanks to a close collaboration between scientist and managers, we highlighted that managers should add topsoil during the creation of Technosols in order to sustain abundance of ecosystem engineers and potentially the ecosystem services they provide.