Woody encroachment threatens the loss of remaining grasslands. Clonal shrubs are of particular concern because of their ability to resprout after disturbance, spread vegetatively, and share resources among interconnected stems. These traits contribute to the encroachment of deep-rooted clonal shrubs in tallgrass prairie. In this study, we investigated how leaf physiological traits differ among interconnected stems within a dominant encroaching shrub in tallgrass prairie, Cornus drummondii.

Woody plants are increasing prevalence and dominance in many rangelands around the world. The reason for their increase is various but two common drivers that have changed are an increase in CO2 concentrations and alteration to precipitation dynamics. We asked what the physiological growth dynamics of four juvenile woody plant species (Cornus drummondii, Rhus glabra, Gleditsia triacanthos and Juniperus osteosperma) when grown in elevated CO2 and chronically water stressed.

ShRaMPs (Shrub Rainout Manipulation Plots) is a drought x fire experiment aimed at understanding the interactive effects of drought and fire frequency on tallgrass prairie communities experiencing varying degrees of shrub encroachment. Passive rainout shelters were constructed over existing, mature shrub islands and co-existing herbaceous communities on neighboring 1-year and 4-year burn watersheds (K1B and K4A). Shelters were either 'control' (ambient precipitation) or 'drought' (~50% precipitation reduction).

Plant xylem water samples were collected from Cornus drummondii (rough-leaf dogwood), Andropogon gerardii (big bluestem), Quercus macrocarpa (bur oak), and Quercus muehlenbergii (chinquapin oak) during the summer of 2016. Soil cores were also collected during the summer of 2016 to collect soil water from the surface to 200 cm depth. Isotope values (δ18O and δ2H) were analyzed for each water sample to determine depth of plant water uptake.