Outside controlled experimental plots, the impact of community attributes on primary productivity has rarely been compared to that of individual species. Here, we identified plant species of high importance for productivity (key species) in >29,000 diverse grassland communities in the European Alps, and compared their effects with those of community-level measures of functional composition (weighted means, variances, skewness, and kurtosis). After accounting for the environment, the five most important key species jointly explained more deviance of productivity than any measure of functional composition alone. Key species were generally tall with high specific leaf areas. By dividing the observations according to distinct habitats, the explanatory power of key species and functional composition increased and key-species plant types and functional composition-productivity relationships varied systematically, presumably because of changing interactions and trade-offs between traits. Our results advocate for a careful consideration of species’ individual effects on ecosystem functioning in complement to community-level measures.

These are the data supporting the results of the Ecology Letters paper "Plant community impact on productivity: trait diversity or key(stone) species effects?", after data preparation.

Description of data included

Site_by_species.csv: Table containing semi-quantitative abundance observations of grassland species (Braun-Blanquet scheme). Column "ID" refers to site ID's. The remaining columns are Taxon names.

Site_by_environment.csv: Table containing information on environmental conditions at observed sites.

"ID": Site ID
"lon": Decimal longitude
"lat": Decimal latitude
"savi_mean_allyear": annual mean SAVI
"savi_nobs_allyear": number of SAVI observations available to calculate annual mean
"temp100_mean": annual mean temperature
"aridiff": annual mean humidity (potential evapotranspiration - precipitation)
"Soil_ind.F_rdf": soil moisture index (derived from plant indiciator values)
"Soil_ind.N_rdf": soil fertility index (derived from plant indiciator values)
"Land_cover": land cover class (CORINE product, see paper)
"Exposition": in degrees
"TWI": terrain wettness index
"clusters5_3d": habitat number, when distinguishing five habitats
"clusters25_3d": habitat number, when distinguishing 25 habitats
"clusters50_3d": habitat number, when distinghishing 50 habitats

Site_by_cwx.csv: Table containing estimates of community-weighted moments, for sites with sufficient trait data coverage. Column "ID" refers to site ID's.

Species_by_trait.csv: Taible containing estimates of traits for taxa with >1% overall occurence frequency.

"Taxon": taxon name
"LNC": leaf nitrogen content
"PL_H_fl": flowering height (in cm)
"SLA": specific leaf area

General comments

The tables Site_by_environment.csv and Species_by_trait.csv contain missing values which are indicated with 'n/a'.

Further information

For more information, please consider the 2022 Ecology Letters paper "Plant community impact on productivity: trait diversity or key(stone) species effects?" by Brun et al.