Drivers of nocturnal water flux in a tallgrass prairie

1. Nocturnal transpiration can impact water balance from the local community to earth-atmosphere fluxes. However, the dynamics and drivers of nocturnal transpiration among coexisting plant functional groups in herbaceous ecosystems are unknown.
2. Here, we addressed the following questions: (1) How do nocturnal (Enight) and diurnal (Eday) transpiration vary among coexisting grasses, forbs, and shrubs in a tallgrass prairie? (2) What environmental variables drive Enight and do these differ from the drivers of Eday? (3) Is Enight associated with daytime physiological processes?
3. We measured diurnal and nocturnal leaf gas exchange on perennial grass, forb, and woody species in a North American tallgrass prairie. Measurements were made periodically across two growing seasons (May-August 2014-2015) on three C4 grasses (Andropogon gerardii, Sorghastrum nutans, and Panicum virgatum), two C3 forbs (Vernonia baldwinii and Solidago canadensis), one C3 sub-shrub (Amorpha canescens) and two C3 ...