Comparing morphological vs eco-physiological traits
To compare the importance of morphological vs eco-physiological traits
in explaining species’ demographic responses, we performed two
additional PCAs: one with only morphological/leaf structural traits
(height, width, Rootd, Rootw, CSI, LMA,
LA, LT, LDMC, C, N and C:N), and another with only eco-physiological
traits (defined as describing internal chemical or physical processes
and their responses to the environment: A, E, GS,
WUEintr, WUEinst, PNUE, R,
GSnight, Enight, δ13C
, δ18O, depth, Topt, Ω and
Q10). We then built LMMs as described above with the two
first axes of both PCA’s to evaluate their ability to predict
demographic change.
To investigate if morphological traits could be used as proxies of
physiology, we first calculated correlation coefficients for each
physiological-morphological trait pair. We then tested if the whole
morphological trait space correlated with the eco-physiological trait
space by performing a co-inertia analysis between the two PCAs (Drayet al. 2003). The significance was tested with a permutation test
(n = 99). Finally, we evaluated how predictions of species’
vulnerability to climate warming would differ if we based the
predictions on either morphological or eco-physiological traits only. To
this end, we ranked species from least to most vulnerable to warming
based on their locations on the trait axes.