PARENT SESSION
Oral Session #106: Plant Ecology: Global Climate Change.
Presiding: D. Breshears
Friday, August 9. 9:00 AM to 12:00 PM. Grand Ballroom East, Radisson.
Effects of warming and clipping on plant species composition in the tallgrass prairie.
Bowdish, Sarah*,1, Wallace, Linda1, Luo, Yiqi1, Wan, Shiqiang1, 1 University of Oklahoma, Norman, Oklahoma
ABSTRACT- The effects of a predicted global temperature increase of 1 to 3.5 degrees over the next century are likely to be complex and highly varied among different ecosystems. Predicting how a species will respond to warming is further complicated by changes in land use and disturbance regimes that are occurring simultaneously. In this study, we looked at how species responded to warming and clipping in the tallgrass prairie by heating plots with quartz heaters to 1.5 degrees C over ambient temperature for 2 years. Each 2 x 2 m warmed and control plot contained subplots, which were either clipped biannually to simulate mowing for hay, an important land use in the Central Great Plains, or left unclipped. Percent cover of individual plant species was estimated using the point count method. We found that warming generally caused significant increases in individual species in spring and fall, but caused species to decrease in summer. The greatest effects of warming on individual species are seen at the end of the growing season in November. Significant increases in the two most abundant C4 grasses (Schizachyrium scoparium, p=.0061 and Sorghastrum nutans, p=.0280) seem to be driving this response. Coverage of both species was positively correlated with soil temperature(S. scoparium, p=.0011 and S. nutans, p=.0280). Clipping had the greatest effect on the abundance of individual species at the end of the growing season. Significant interactions between clipping and warming were observed in both spring and fall, but not summer.
KEY WORDS: tallgrass prairie, temperature, Schizachyrium scoparium, clipping