(A) Photograph of the field site of the Jena Experiment taken in 2004 showing the main experimental plots (20×20 m) varying in plant species richness (1, 2, 4, 8, 16, and 60) and plant functional group richness (1, 2, 3, and 4) and the X- (horizontal axis; coordinates 0–4) and Y-coordinates (vertical axis; coordinates 0–6). Photo by J. Baade. (B) Photograph of one exemplary earthworm subplot (1×1 m), the enclosures for earthworm density manipulations (earthworm addition and earthworm reduction), and four octet devices used for earthworm extraction by electro-shocking. Photo by N. Eisenhauer. (C) Photograph of one exemplary Lumbricus terrestris midden with three invader seedlings on the field site of the Jena Experiment. Photo by N. Eisenhauer.