Data from: Plant intraspecific functional trait variation is related to within-habitat heterogeneity and genetic diversity in Trifolium montanum L.

Intraspecific trait variation (ITV), based on available genetic diversity,
is one of the major means plant populations can respond to environmental
variability. The study of functional trait variation and diversity has
become popular in ecological research, e.g. as a proxy for plant
performance influencing fitness. Up to now, it is unclear which aspects of
intraspecific functional trait variation (iFDCV) can be attributed to the
environment or genetics under natural conditions. Here, we examined 260
individuals from 13 locations of the rare (semi-)dry calcareous grassland
species Trifolium montanum L. in terms of iFDCV, within-habitat
heterogeneity, and genetic diversity. The iFDCV was assessed by measuring
functional traits (releasing height, biomass, leaf area, specific leaf
area, leaf dry matter content, Fv/Fm, performance index, stomatal pore
surface, and stomatal pore area index). Abiotic within-habitat
heterogeneity was derived from altitude, slope exposure, slope, leaf area
index, soil depth, and further soil factors. Based on microsatellites, we
calculated expected heterozygosity (He) because it best-explained, among
other indices, iFDCV. We performed multiple linear regression models
quantifying relationships among iFDCV, abiotic within-habitat
heterogeneity and genetic diversity, and also between separate functional
traits and abiotic within-habitat heterogeneity or genetic diversity. We
found that abiotic within-habitat heterogeneity influenced iFDCV twice as
strong compared to genetic diversity. Both aspects together explained 77%
of variation in iFDCV (Radj² = 0.77, F2, 10 = 21.66, p < 0.001).
The majority of functional traits (releasing height, biomass, specific
leaf area, leaf dry matter content, Fv/Fm and performance index) were
related to abiotic habitat conditions indicating responses to
environmental heterogeneity. In contrast, morphology-related functional
traits (releasing height, biomass and leaf area) were only related to
genetics. Our results suggest that both within-habitat heterogeneity and
genetic diversity affect iFDCV, and are thus crucial to consider when
aiming to understand or predict changes of plant species performance under
changing environmental conditions.