Ecophysiology, Global Change, and Ecosystem Function
How do we scale physiological processes up to ecosystems?
I combine plant ecophysiological experiments with satellite data to understand the constraints of climate on plant functional types (C3 or C4 grasses) and how climate dictates the sensitivity of grasslands to drought.
C4 grasses typically exist in hotter, more arid ecosystems than C3 grasses. Furthermore, C3 grass physiology is extremely drought sensitive due to their photosynthetic pathway. However, the paradox is that C4 grasslands, especially arid grasslands, are extremely drought sensitive compared to C3 grasslands. Physiology experiments have demonstrated that C4 grasses do tolerate drought better. However, placing C4 grass physiology into environmental context using satellite estimates of soil moisture demonstrate that C4 grasses often exist closer to their physiological threshold than C3 grasses. As a result, C4 grasslands typically experience more severe declines in production due to drought than do C3 grasslands.