Data collection
In 2013, after three years of nutrient addition, in the subplots
dedicated to measuring aboveground plant biomass through time, we
sampled twenty common species accounting for 85 ± 10% of aboveground
biomass (Table S1). For each species, we randomly selected, dried at
80°C and weighed 12 individuals on days 146, 157, 167, 177, 197, 207,
238, and 254 in the year of 2013. We stopped sampling species once they
were in full flower, resulting in a lower number of species sampled
after day 177. In the subplots dedicated to measuring aboveground plant
biomass and species composition at peak biomass, the vegetation was
clipped in mid-August 2013 at soil level in one randomly selected 0.5 x
0.5 m quadrat, sorted to species, dried at 80°C and weighed.