Response of soil biota to manipulation of collembolan biomass

We report on a microcosm experiment to test the impact of manipulating collembolan biomass on the composition and ecological functions of soil biota. Three different treatments were established corresponding to low, ambient or high biomass of Collembola. After 10 weeks, the biomasses of predators were significantly correlated to the collembolan biomass introduced within the microcosms. Non-predatory groups were not impacted by the different treatments. Microbial biomass and carbon mineralisation were both significantly highest in the Ambient treatment at the end of the experiment. These show the importance of trophic interactions as short-term driver of soil communities and of changes in soil carbon mineralisation. Our results also suggest that ecological processes within clumps of Collembola will be affected by their numbers showing highly non-linear ecosystem function effects.