Correlation between plant functional traits and chemical diversity
The results of the coinertia analysis revealed a significant correlation between the matrix of plant functional traits and the GSL matrix (Fig. 2; r = 0.49, p = 0.01), which grouped species according to common habitat-driven growth forms and GSL diversity scheme. Group1 was composed of species having higher chlorophyll levels, tough leaves, low SLA and low herbivore damage, typical of alpine species (C. alpina, C. resedifolia, C. rivularis , and C. amara ). Group 2 was composed of species with high biomass, particularly of mid-elevation forest species (C. kitaibelii, C. pentaphyllos, and C. heptaphylla ). Group 3 was composed of species from mid-to-high elevation species growing in grasslands or in forest edges (C. trifolia and C. pratensis ). Group 4 was composed of species with high SLA, low SPAD and high herbivore pressure, typical of low-elevation inhabiting species (C. hirsuta, C. impatiens, C. flexuosa, C. matthioli and C. bulbifera ) (Fig. 2 and Fig. 3). Scoring from the LDA analysis highlighted that methoxyglucobrassicin and glucobrassicin are the GSLs characteristic of group1, 2-methy-butyl-GSL of group2, butyl GSL of group 3, and glucobrassicin and hydroxyglucobrassicin of group 4 (Fig. 3, Table S3).