Inoculation of an ecosystem engineer (Earthworm: Lumbricus terrestris ) during experimental grassland restoration: Consequences for above and belowground soil compartments

•Earthworms (L. terrestris) were inoculated in grassland devoid of earthworms.•Chemical soil properties were not impacted by earthworm inoculation.•The plant productivity was doubled, and grass species were favored over forbs.•Earthworm inoculation also had a negative impact on Collembola richness.•Earthworm inoculation could directly and indirectly alter above-belowground linkages.