Plant community impact on productivity: the interplay of community-level
functional attributes, species, and environmental selection
Abstract
While the impact of biodiversity, notably functional diversity, on
ecosystem productivity has been extensively studied, little is known
about the effect of individual species. Here, we identified species of
high importance for productivity (key species) in over 28,000 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 than all statistics of functional composition.
Key species were generally tall with high specific leaf areas. By
dividing the observations according to distinct habitats, the
explanatory power of all non-environmental predictors increased
considerably, and the relationships between functional composition and
productivity varied systematically, presumably because of changing
interactions and trade-offs between traits. Our results advocate for a
better consideration of species’ individual effects on ecosystem
functioning in complement to community-level measures.