Defining extremes in extreme environments

Organisms in drylands experience some of the most extreme climatic conditions on the planet including drought, heat, and precipitation variability. While dryland organisms have adaptions for such extremes, a predicted increase in the frequency and intensity of extreme events may push them beyond their adaptive capacity, leading to state changes and loss in ecosystem services. A key question is: how do you define extreme events in such an extreme environment? Here I will examine extremes in drylands from both climatological and ecological perspectives. Defining extremes is a critical step for forecasting the vulnerability of drylands to a changing climate.