Macall Teague

1 Introduction In desert ecosystems, perennial vegetation is often composed of plants that extract water from the phreatic zone (groundwater and capillary fringe). Groundwater access helps vegetation maintain transpiration, carbon uptake and cooling capacity, particularly during long spells of hot-dry conditions (Mu et al. 2021). Indeed, evapotranspiration (ET) is often the primary driver of groundwater discharge in desert environments (Robinson and Waananen 1970; Nichols 1993, 1994).

1 Introduction Drylands and deserts have low average rates of primary production, yet vegetation function and productivity in these systems can influence inter-annual variation in the global land surface C sink (Poulter et al. 2014; Ahlström et al. 2015). Water inputs and water availability are key drivers of plant function and growth in drylands and deserts (Biederman et al. 2018).