Long-term species richness and evenness trends in response to N addition and elevated CO2 in BioCON

The data and code in this package are associated with the analysis for a manuscript titled "Elevated CO2 first dampens but then amplifies diversity loss due to N enrichment over 24 years". The files include 24 years of data on species cover, total aboveground biomass, species richness, evenness and environmental variables from the BioCON experiment. The complete BioCON (Biodiversity, CO2, and N) experiment includes 371 2 x 2 m plots in six circular 20-meter diameter rings, located at the Cedar Creek Ecosystem Science Reserve in Minnesota, USA. Plots were established on secondary successional grassland on a sandy outwash soil after removing the prior vegetation. The BioCON project includes several overlapping and nested experiments.