The Inner Bluegrass Region of Kentucky that the 18th century pioneers described was a highly productive and diverse habitat. While being part of the Mixed Mesophytic Forest, parts of this area were surprisingly described as Blue Ash-Oak Savanna with extensive open mixes of trees and grasses. Savannas are usually associated with distinct dry periods so it is unexpected to find this habitat in Kentucky’s temperate climate. Disturbance is thought to play an important role in this system so what could have maintained this system was topography, fire, extended drought, or grazing by bison, elk, and deer. Since the Bluegrass Region was the first area in Kentucky settled by Europeans, followed by a rapid conversion to agriculture, little evidence of this original landscape remains. Most research done on the Blue Ash-Oak Savanna is focused on the tree species, while little is known of the species diversity or community assembly of the grasses. This study focuses on the ecology of four native bunchgrasses that were likely a part of this system.
We measured the effect of simulated herbivory at two clipping heights (8 cm and 4 cm) clipped once a week, on two C3 grasses (Andropogon virginicus and Chasmanthium latifolium), and two C4 grasses (Tridens flavus and Panicum anceps).
Results/Conclusions
Total biomass (above and below ground) of all four species was negatively affected by clipping compared to the controls with the two C3 species generally more affected than the C4 species. All four species shifted to increase shoot allocation and reduce root allocation in response to clipping. The two clipping heights had similar regrowth. The number of mature leaves or photosynthetic capacity was also negatively affected by all four species.
