Data from: Harsh environmental regimes increase the functional significance of intraspecific variation in plant communities

The relative importance of intraspecific trait variation (rITV) for
functional diversity (FD) in plant communities is increasingly apparent,
but the influence of abiotic factors on the balance between intraspecific
and interspecific effects in contrasting environments is uncertain. We
predicted that rITV would increase with environmental harshness
as a result of decreasing interspecific variation (Inter_FD) and
concomitant increases in between-population ITV(Intra_FD). We empirically
tested this prediction in a comparison of rITV for five traits (mature
plant height, SLA: specific leaf area, leaf dry matter content, and the
foliar concentrations of nitrogen and phosphorus) characterizing species
in Tibetan alpine meadow communities from contrasting environmental
regimes(i.e. valley floor at the base of the ridge, northern- and
southern-slopes at mid-elevation, and ridge top) on each of three sites
(ridges). We found that across plots: i) rITV for all five traits
increased with environmental harshness not only through decreasing
Inter_FD but also increasing Intra_FD; ii) increases in rITV were mostly
attributable to declines in soil resources, especially soil phosphorus,
with lower soil P significantly associated with lower Inter_FD but higher
Intra_FD for most traits; and iii) although neither Intra_FD nor Inter_FD
were significantly impacted by species richness for any traits, a higher
rITV for SLA was significantly associated with low species richness.