1. Introduction . An increase in drought events driven by anthropogenic climate change has been observed globally [ 1 ] and is likely to have profound ecosystem impacts in semiarid lands. For example, a state of megadrought persisting in the western United States over the past 20 years has been attributed to climate change [ 2 ], and drought events in the region are anticipated to increase in frequency and severity over the next century [ 2 , 3 ]. A drought event in New Mexico during...