Data processing
To extract parameters from the photosynthesis-temperature response
curves (Figure S2), we fitted an equation after June et al.(2004), yielding two parameters: optimal temperature for photosynthesis
(TOpt) and the temperature range for photosynthesis (Ω ;
at which photosynthesis falls to e-1 of its value at
Topt, Eq. S1). To estimate respiration sensitivity to
temperature (Figure S3), we fitted an exponential equation, estimating
the change in respiration rate with a temperature increase of 10°C
(“Q10, Eq. S2-S3, Tjoelker et al. 2001; Atkinet al. 2005).
We calculated a measure of plasticity for all the traits that had been
collected from more than one site (Table 2). For traits measured at all
the four sites we calculated a simplified relative distance plasticity
index (“RDPIS”) after Valladares et al. (2006).
The index ranges from 0 (no plasticity) to 1 (maximal plasticity) and is
calculated as the sum of absolute trait differences divided by the sum
of the traits (Eq. S4), and is recommended for ranking species according
to their plasticity (Valladares et al. 2006). For traits that
were measured in only two treatments, we used the same approach (i.e.
(mean at lower elevation – mean at origin) / sum), but with a signed
(+/-) rather than absolute value of the trait differences, so that we
could measure the direction of change between the two sites (Eq. S5).