Environmental and climatic variables
The same plant species analysed were previously described in term of
their climatic niche, as well as in term of their growth-related
functional traits (Defossez et al. 2018). We therefore used
species’ average of several functional traits related to natural
herbivore damage 1) % damage, and to growth; 2) specific leaf area
(SLA), 3) plant biomass, 4) plant height, 5) chlorophyll content, and 6)
leaf toughness, to assess a potential correlation between plant growth
forms and GSL diversity. In short, herbivore damage was measured as
percent increments on 10 randomly-sampled plants per species in their
natural environment. SLA (mm2 mg-1DW), was measured as the area of a 1 cm leaf disc divided by its dry
mass; chlorophyll content was measured as SPAD values using a SPAD 502
Plus Chlorophyll Meter (Konica, Minolta, Tokyo Japan); leaf toughness (g
mm2) was measured with a custom made hole puncher;
weight (g) was measured as the total dry aboveground plant biomass, and
height (cm) was measured from the soil till the highest leaf (n = 10
plants per species and per trait; Table S1 in Supplementary material).