Effects of elevated CO2 and defoliation on grasses: A comparative ecosystem approach
Wilsey BJ, Coleman JS, McNaughton SJ. 1997. Effects of elevated CO2 and defoliation on grasses: A comparative ecosystem approach. Ecological Applications. 7(3):844-853
Three plant species from each of three grassland ecosystems were grown under elevated (700 mL/m(3)) and ambient (350 mL/m(3)) CO2 and were defoliated or left undefoliated to test whether species response to elevated CO2 and grazing is related to evolutionary grazing history or to mode of photosynthesis. Elevated CO2 caused an increase in total biomass and total productivity (biomass + clippings) only in Yellowstone species, and increases in growth occurred primarily in crowns and roots (storage organs).. There was no interaction between CO2 and defoliation for any species; thus, it appears that herbivores will not affect how grasses respond to elevated CO2 (at least under average nutrient conditions). Elevated CO2 caused a reduction in leaf percentage of N in species from Yellowstone . Because the quantity of food was unaffected by the CO2 treatments and forage N was reduced, grazing mammals may be negatively affected. We suggest that the lower intensity and increased temporal variance in grazing pressure in Yellowstone vs. the Serengeti selected for plants that shift allocation away from roots and crowns in order to compensate for aboveground herbivory.
- Type
- Journal Article
- Authors
- Wilsey, Brian; Coleman, J; McNaughton, Samuel
- Units
- YELL
- Keywords
- Carbon Dioxide, Ecology, Grassland, Grazing, Nitrogen, Plant Studies