Get reliable rangeland science

North American mesic grasslands occupy a unique ecosystem space where frequent disturbance and climate variability intersect. Mesic tallgrass prairie is typically characterized by few highly productive C4 grass species, but includes diverse assemblages of other forbs, grasses, sedges, and woody plants. Species persistence in this ecosystem requires tradeoffs that balance competitive efficiency for resources, and an ability to tolerate (or avoid) frequent disturbance. Over the past 30 years, woody shrubs have increased dramatically in grasslands, shifting the ecosystem state from grassland to shrubland across landscapes. These alternative stable states have resulted from reductions in fire frequency, habitat fragmentation, and climate change. What unique attributes of woody shrubs have shifted the balance of power from C4 grasses to shrubs in grasslands? In this presentation, I will discuss the significance of physiological and morphological characteristics among C4 grasses and C3 woody shrubs within the context of frequent disturbance and drought. The physiological traits employed by these dominant growth forms influence water stress, uptake, and overall water flux. Ultimately, distinct traits and ecohydrological strategies among grasses and shrubs are key regulators of the rates and trajectories of woody encroachment in the tallgrass prairie.