Urban belowground food-web responses to plant community manipulation - Impacts on nutrient dynamics

Plant species producing labile litter (legume Lotus and grass Holcus) produced a higher bacterial energy channel biomass in comparison to plants (Calluna and Picea) producing recalcitrant litter. The bacterial-dominating energy channel under Lotus plots leached higher amount of inorganic nitrogen than the plots with Calluna and Picea, which had relatively higher proportion of fungal biomass in the soil. However, when the leaching loss was compared to the potentially leachable soil inorganic nitrogen, the most species-diverse mixed communities, albeit increasing the bacterial biomass, showed a highest capacity for conserving nitrogen in the soil. Our study demonstrates the great potential of plant species/functional types to modify the urban belowground communities and consequently, the nutrient dynamics of disturbed urban soils.