Figure 1.

Interaction plots for T_crit-hot,T_crit-cold and TTB across biomes and treatments. (a) Interactions between biome, hot days and cold nights demonstrating that each treatment increased T_crit-hot, with the strongest effect from the hot days treatment while that, overall, the responses across biomes followed the same pattern. (b) Interaction plots for T_crit-cold indicate that desert and temperate plants showed little change after treatments, whereas alpine plants followed a different pattern and decreased cold tolerance after exposure to any combination of hot days or cold nights. (c) Interaction plots for TTB show hot days increased TTB for all biomes but to a much lesser extent for the alpine group, in which TTB narrowed in response to exposure to cold nights. No plants showed capacity for bi-directional expansion of TTB. Values are linear mixed effects model means ± SE.