Figure 1. The interaction between warming and trait value, as
a) the second axis of the PCA including all traits combined (describing
plant size and water use strategy), as b) the second axis of a PCA with
morphological traits only (describing plant size) and as c) the second
axis of a PCA with ecophysiological traits only (describing water use
strategy). Larger trait values correspond to larger size and/or more
conservative water use strategy, as indicated by the arrow. Note that
the axis in panel c) has been inverted to make the comparison between
the panels easier. Lines are model predictions, points are raw data. The
y-axes are changes in frequency (i.e. final/initial), in order to
visualize the trends while taking into account the differences in
initial frequency. The grey dashed line represents a relative frequency
of 1, i.e. separating “losers” (below the line) from “winners”
(above the line). For cover changes, see Supporting Information Figure
S11a,c,d.
Figure 2. Species position in the trait space based on a)
morphological traits only and b) ecophysiological traits only, c-d)
indicating the traits governing the trait space. The first morphological
axis describes leaf structure, and the second morphological axis
describes plant size. The first ecophysiological axis describes plant
gas exchange and the second ecophysiological axis describes integrated
water use strategy. For both PCAs, the second axis correlates with
species’ cover and frequency change to warming. In addition, the first
morphological axis correlates with species cover change. Species are
colored according to their position on the second axis, because for both
PCAs, the second axis correlates with species’ cover and frequency
change to warming; red colors indicate species less vulnerable to
warming according to that trait axis. For the PCA including all traits
combined, see Supporting Information Figure S10.
Figure 3. Community-weighted means for δ18O
(correlating negatively with life-time stomatal conductance) and
δ13C (correlating positively with life-time water use
efficiency). Panels a) and c) show changes in community mean values when
only changes in species frequency are taken into account (i.e. mean
species trait values measured at +0°C). Panels b) and d) show changes in
community-weighted values when both changes in species frequency and
intra-specific trait changes are taken into account (i.e. site-specific
trait values). See Supporting Information Figures S5-S6 for
intra-specific changes in traits due to warming. The overall
community-level effect of the transplantation was significantly higher
life-time stomatal conductance (GS; lower δ18O;
F(1,48) = 90.93, p < 0.001, panel b) and lower life-time water
use efficiency (WUE; δ13C; F(1,48) = 8.75, p = 0.005m
panel d) at the warmest site (1000 m, +5°C).
Figure 4. Relationship between species’ vulnerability to
climate change based on morphological or ecophysiological traits only.
Panel a) shows species ranked from most vulnerable to warming (1) to
least vulnerable (16), according to their position on the second trait
axis of the PCA with morphological or ecophysiological traits only (i.e.
describing either size or water use strategy). The dashed line indicates
1:1 relationship, i.e. the further the species falls from the line, the
more different are the two rankings for that species. Panel b) shows the
correlation with the trait axes themselves.