Syracuse

1. Many biodiversity-ecosystem functioning (BEF) experiments have shown enhanced productivity with biodiversity, often explained by niche differentiation and complementarity effects. Yet, most of these results are based on artificial plant assemblages, with a major focus on above-ground productivity. Consequently, our comprehension of the BEF relationship in natural ecosystem and for belowground functions remains largely unknown.

2. In this study, we simulated a long-term non-random species loss in a naturally diverse temperate meadow. We created a richness gradient spanning from 1 to more than 20 species per plot, removing the rare and sub-ordinate species from the vegetation. After 3 and 6 years of experimental manipulation, soil cores were collected to investigate the effects of species removal on below-ground biomass, vertical distribution of roots and root traits. We also used ingrowth cores to quantify the short-term root production of plant communities. We investigated the consistency of below-and above-ground responses to species removal.

3. Consistent with above-ground responses, species removal had little effect on root biomass and community root traits, except for a decrease in biomass in the uppermost soil layer (0-5 cm) found only after 6 years. Similarly, the vertical distribution of root biomass and traits was largely unaffected by diversity loss, suggesting little evidence for vertical niche differentiation. Nevertheless, species loss decreased the root production in spring (3 months), albeit this lower shortterm root production was diluted after a year, when monocultures of dominants almost matched the annual root production of controls.

Our results from a non-random species removal experiment revealed minimal impact of a realistic diversity loss on root biomass and traits, but a decrease in short-term fine root production. These results challenge traditional O RCI D