With ~40% coverage of the terrestrial biosphere, grasses represent one the major plant types on Earth; this percentage excludes additional coverage by all major grain crops, which are also grasses. Despite the global importance of grasses, significant gaps in understanding remain in how grasses respond to drought. The evolution and expansion of grassland biomes came at the expense of forests and was precipitated by an increase in aridity; therefore, grass evolution, physiology, and ecology are inextricably linked to the acquisition, use, and movement of water. The aim of this proposal is to provide a better understanding of grass physiological responses to drought from the cellular to ecosystem scales. The current understanding of plant responses to drought is dominated by data on woody plants, particularly trees, and this understanding does not translate readily to grasses. Elucidation of these drought response will enhance our understanding of wild grasses to drought, as well as discover relevant physiological responses for crop improvement. Additionally, the PIs will conduct the immersive data-collection and instrument training ecophysiology workshop for graduate students (Phys-Fest). This Phys-Fest will occur in the urban environment of Philadelphia. Urban environments can provide key ecosystem services, and when explicitly managed, these environments enhance overall human well-being. Participants are trained in four primary ecophysiological research areas and are provide