Data and code from: Plant species responses to nutrient addition, but not to herbivore exclusion, strengthen over time in global grasslands

Using long-term data from the Nutrient Network (NutNet), a globally distributed experiment, we examined how grassland plant community composition responded to factorial nutrient addition (NPK) and herbivore exclusion (fencing) across 98 sites and up to 12 years of treatment.

For each site and year, we quantified the overall compositional difference between treatments (PERMANOVA), identified the species contributing most to those differences (SIMPER), and classified species as indicators of each treatment (Indicator Species Analysis), linking these responses to each species' dominance, commonness, functional group, lifespan, and provenance. We found that compositional divergence under nutrient addition strengthened over time and was driven disproportionately by a relatively small subset of species, particularly dominant and common ones, whereas the effects of herbivore exclusion were comparatively weak and transient.