What to expect from restored Cerrado grasslands? Indicators and reference values from pristine ecosystems

Open ecosystems are disappearing worldwide, requiring urgent restoration efforts. However, limited knowledge of their structure and composition hinders the assessment of restoration success. We aimed to establish reference values for plant community attributes in undisturbed native grasslands to guide restoration. In an unprecedented data collection, we sampled 14 remnants under different climate, soil, and fire regimes, representing a broad portion of the Brazilian savanna (except the least converted northern). We assessed plant community composition, richness at different scales, ground cover by functional groups, and aboveground biomass. From the 794 species recorded, half were unique occurrences, and few were present in over 70% of the sampled areas. Richness ranged from 9 to 22 species/m 2 and 53 to 130 in 30 m 2 . Grasses (22–80%) and non‐grasses (9–45%) did not cover the ground entirely, leaving 4–56% exposed. Biomass ranged from 57 to 715 g/m 2 . Because species composition is variable, finding a “reference set” of species for the whole Cerrado is not possible. Regional subsets and key functional guilds are recommended instead. The number of species/m 2 is a good proxy for diversity, and species/30 m 2 is a good reference for total richness. Biomass is an unreliable indicator due to the broad natural range independent of integrity. The maximum biomass, however, should never be surpassed. Structural targets should include grasses, non‐grasses, and bare soil within the reference range, but achieving pristine plant richness may be unrealistic in most cases. Strong efforts should focus on conservation rather than restoration, once recovering all the reference's attributes is difficult.