Abstract One hundred and twenty years after restoration of badlands by reforestation with Pinus nigra Arn. ssp. nigra, the analysis of the soils on marls of the Saignon experimental watershed (Alpes-de-Haute-Provence) demonstrates the potentialities and the driving forces behind the distribution of earthworms in the main site types. The communities are young, and density and biomass are low to normal (up to 49 individuals and 27 g·m −2, respectively) for these low productivity pine woods. Two main site-directed trajectories would lead marls to a mixed species association: the first one is initiated by the epi-anecic behaviour of Lumbricus terrestris L. in xeric conditions (south-oriented slope, thin soil); the second is initiated by Octolasion cyaneum Sav. (north-oriented slope).