Provenance level differentiation in thermal tolerance
At the common garden experimental site, mean Tcrit was 46.0 °C and ranged from 42.0 to 51.1 °C (Figure 3a). For C. australe , we found moderate evidence of a provenance effect on Tcrit (t (10) = −2.46, p = 0.0336), with the lowland provenance having a lower T­crit than the upland provenance, averaging 46.6 °C ± 2.81 and 49.6 °C ± 1.05 respectively (Figure 3a). For T. microcarpa , we found weak evidence for a provenance effect (t (10) = 1.85, p = 0.0947), with Tcrit averaging 47.7 °C ± 2.07 and 45.8 °C ± 1.41, for the lowland and upland provenance respectively (Figure 3a). We found no evidence for a provenance effect on Tcrit for H. novo-guineensis or M. elleryana (p > 0.05).
The mean thermal tolerance metric T50 was 49.7 °C overall and ranged from 46.6 to 54.7 °C (Figure 3b). We found no evidence for provenance-differentiation in T50 in any of the species (p > 0.05; Figure 3b).