Predicting how plant communities will respond to environmental change has been described as the ‘holy grail’ of ecology. Understanding which factors determine whether a species responds positively or negatively to a particular environmental change allows us to anticipate future shifts in community composition. Nowhere is this understanding more urgent than in tundra ecosystems, where temperatures are rising faster than anywhere else on the planet, and shifts in plant community composition can have global consequences due to vegetation-climate feedbacks4.
A species is more likely to be able to endure environmental change in situ if the degree of plasticity is large enough to withstand the magnitude of environmental change. Thus, the temperature sensitivity of traits may be particularly critical to coping with rapidly warming environments. A study of (non-tundra) phenological responses to experimental warming found that species with more temperature-sensitive phenology had improved growth and reproductive success. However, this theory has never been tested on traits in tundra ecosystems, where slow growth and long lifespans suggest that the ability of a plant to respond plastically to change is particularly important. Furthermore, it is unknown if the temperature sensitivity of traits is important in determining species’ responses to environmental change. By conducting in situ field experiments on experimentally warmed and control plots we will be able to determine to what degree an individual’s traits vary in concert with temperature.