Figure legends
Fig. 1. Thermal thresholds T50 (a,b) and
TCrit (c,d) as a function of elevation and mean annual
temperature for 150 tropical species. Values for CAM plants and
C4 plants are indicated in red and blue, respectively.
Black and red lines and r2 values indicate linear
regressions for the full dataset and for C3 plants only,
respectively. For C3: a)
T50=50.4–0.0026 × Elevation (m asl). b)
T50=39.3+0.41×MAT. c) TCrit=47.4–0.0039
× Elevation. d) TCrit=31.2+0.60×MAT.
Fig 2. Thermal thresholds T50 and
TCrit in relation to elevation for species that were
measured at two contrasting elevations. Error bars indicate 95%
confidence intervals approximated as T50 ±1.96 ×
standard error of T50. 1. Posoqueria latifolia ,
2. Aspidosperma spruceanum , 3. Protium panamense , 4.Ceiba pentandra , 5. Coccoloba uvifera , 6. Podocarpus
guatemalensis , 7. Guatteria lucens .
Fig 3. Relationship between thermal thresholds
T50 and TCrit and species ‘ages’. Gray
diamonds show data for Chrysophyllum cainito , a sister species ofC. argentum dated in Dick et al . (2013). Species names in
blue represent Pleistocene; green, Pliocene; red, Miocene.
Fig. 4 . Phylogenetic tree of study species with branches color
coded by the value of T50 standardized to sea level. Red
and blue arrows indicate CAM-exhibiting species and C4species, respectively. Black nodes represent polytomies.
Fig. 5 . Leaf critical temperature (TCrit) as a
function of the estimated thermal time constant (log τ) and elevation.
Solid and dashed lines indicate significant and non-significant
correlations for lowland and non-lowland data, respectively. Shaded
areas indicate 95% confidence intervals of the predictions. Boxplots
illustrate lowland (open bars) vs non-lowland (mid-elevation and
pre-montane) sites (closed bars). ** P <0.001).
Fig. 6 . T50 as a function of leaf mass per area
(LMA) and elevation. Solid and dashed lines indicate significant and
non-significant correlations for lowland and non-lowland data,
respectively. Shaded areas indicate 95% confidence intervals of the
predictions. Boxplots illustrate lowland (open bars) vs non-lowland
(mid-elevation and pre-montane) sites (closed bars). * P<0.05, ** P <0.01).
Table 1 . Geographic and temperature data for the sample sites.
TMin is the mean minimum temperature of the coolest
month, MAT is mean annual temperature and TMax is the
mean maximum temperature of the warmest month.