Data from: Linking species abundance and overyielding from experimental communities with niche and fitness characteristics

1) So far, the principal force shaping local plant abundance patterns
remains unclear. Rarity can result from poor competitive ability or from
small vegetative or generative reproduction, but also from strong
self-limitation. The same mechanisms can drive species-specific
overyielding, i.e. increased species productivity at high community
diversity. Rare species can then benefit more (i.e. overyield to a larger
extent) from growing in species-rich communities because of altered
competitive hierarchies or smaller conspecific frequencies. Here we test
which mechanism is the most important determinant of species rarity and of
species-specific productivity across a diversity gradient ranging from
one- to 60-species plots. 2) For that we measured vegetative growth,
competitive ability (competitive effect), and negative frequency
dependence for 49 perennial grassland species from Central Europe. We then
linked these characteristics with species abundance (measured as species
biomass from 60-species plots) and with species-specific overyielding in
The Jena Experiment. 3) Species with higher rates of vegetative growth
(when grown without neighbors) were also more abundant in the Jena
Experiment. Larger species-specific overyielding was then associated with
a stronger negative frequency dependence. As species with greater
vegetative growth were also more self-limited, larger overyielding in
species-rich communities was characteristic for common rather than for
rare species, refuting our initial hypothesis. Finally, path analysis
indicated that species with poor capacity to suppress neighbors also
profited more from growing in diverse communities. 4) Synthesis. Our
results identify key mechanisms driving abundance and productivity of
species in synthetic communities differing in species richness. While
vegetative reproduction was closely associated with abundance,
intraspecific interactions (strength of negative frequency dependence)
shaped species productivity across a richness gradient. Our study sheds
light on the abundance patterns of species and their influence on
community functions, such as biomass production, of species-rich and -poor
vegetation.