Fig. 1

Schematic illustration of the experimental design. (A) Examples of possible scenarios outlining the impact of increasing physical distance between the neighboring cells (x-axis) on the importance of biotic interactions between microbial species (y-axis). Negative and positive interactions are represented in red and blue, respectively. (B) In the first step, the physical distance between microbial cells was experimentally manipulated by introducing the same species pool into increasing volumes of sterilized soil (n = 10) for control, heat-shock and ramoplanin communities. (C) Step 2 consisted in a coalescence experiment with a reciprocal transplant design by mixing microbial communities that assembled at high (d1) or low (d2) densities during step1 in sterile soil (coalesced communities). Soils colonized under the d1 and the d2 initial densities were also incubated separately with sterile soil at high (d1) or low (d2) densities (reference communities)