1) Interactions among neighbors can alter demography and traits of commingled species via adaptation or plasticity in phenotypic expression and understanding these two mechanisms in diverse communities is important for determining the ecological and evolutionary consequences of plant–plant interactions.

2) We reciprocally transplanted perennial species (Arenaria armerina and Festuca indigesta) among patches of two foundation shrub species and open ground to assess whether origin microsite (defined as the spatially distinct abiotic and biotic conditions associated with the two shrubs and open ground) determines germination, recruitment and growth that, in turn, promotes fine-scale distribution of species among microsites. In addition, we tested the effect of origin microsite on traits, competitive ability, drought tolerance and outlier loci to assess whether origin microsite conditions drove differences in traits, strategies and adaptive loci.

3) Germination was consistently greater for seeds planted back into their origin microsite relative to seeds sourced from foreign microsites, although this effect was weakened for recruitment. Plant growth was best in open sites regardless of origin microsite. In the greenhouse, A. armerina had conserved traits within origin microsite but distinct trait values among microsite conditions, specifically for plants originating from the most productive microsite (e.g. sufficient light and high nutrients and water availability). Festuca indigesta had conserved trait responses among microsites while within microsite, individuals had significant trait plasticity to different environmental conditions. The combined field and greenhouse results suggest that fine-scale distributions are supported by local adaptation among microsites of A. armerina and phenotypic plasticity of F. indigesta.

Synthesis Adaptation or plasticity in phenotypic expression have different implications for demographic rate and persistence of species in changing environments. Local adaptation to neighbors suggests that reductions in foundation species diversity could concomitantly lead to reduced genetic diversity of commingled species while a plastic response indicates a more robust and broad response to changing climatic and biotic conditions.

These data sets represent work from two experiments: a reciprocal transplant in the Sierra Nevada, Spain (36.9845°N, 3.3232°W) and a greenhouse common garden at the University of Zurich. Data from the field experiment includes the biomass of plants after two growing seasons, germination from season 1 and season 2, recruitment after 2 seasons and the environmental conditions measured in the three microsites. Data from the greenhouse include traits (LMA and LDMC) from control and drought treatments.

There is a ReadME file with the data that provides all descriptions of the columns and units. The vcf file contains the raw SNP data (840652 SNPs).