Drivers of species-specific contributions to the total live aboveground plant biomass in Central European semi-natural hay grasslands

•Species-specific biomass and community structure in grasslands was studied.•Nearly half of the total aboveground biomass was dependent on non-dominant species.•Infrequent and non-dominant species were the core of the diversity seen in grasslands.•Biomass inequality among species decreased with increasing functional diversity.•Species-specific biomass was mostly influenced by soil pH and management.