Belowground Water-use Traits of Savanna Trees and Grasses

Water is a key limiting resource for plants in savannas. Therefore, the belowground functional traits responsible for water transport are likely essential to understanding the tree-grass dynamics of savannas. We found that tree and grass species from a Lowveld savanna ecosystem differ in their root conductive anatomy and that grasses had a greater capacity to transport water than trees. We also found a significant relationship between the growth rate and the vascular traits of the trees and grasses we studied. When examining the conductivity of whole root systems of trees, we found that axial conductivity values were significantly related to whole root conductivity. These results demonstrate the critical importance of root water transport capacity to the form and function of savanna plants. Understanding the water-use strategies of trees and grasses will prove vital in predicting how future changes in climate and precipitation patterns will affect savanna plant communities.