title: Response of an allergenic species, Ambrosia psilostachya (Asteraceae), to experimental warming and clipping: implications for public health.
abstract: We examined the responses of an allergenic species, western ragweed (Ambrosia psilostachya DC.), to experimental warming and clipping. The experiment was conducted in a tallgrass prairie in Oklahoma, USA, between 1999 and 2001. Warming increased ragweed stems by 88% when not clipped and 46% when clipped. Clipping increased ragweed stems by 75% and 36% in the control and warmed plots, respectively. In 2001, warming resulted in a 105% increase in ragweed aboveground biomass (AGB), and the ratio of ragweed AGB to total AGB increased by 79%. Dry mass per ragweed stem in the warmed plots was 37% and 38% greater than that in the control plots in 2000 and 2001, respectively. Although warming caused no difference in pollen production per stem, total pollen production increased by 84% (P < 0.05) because there were more ragweed stems. Experimental warming significantly increased pollen diameter from 21.2 μm in the control plots to 23.9 μm in the warmed plots (a 13% increase). The results from our experiment suggest that global warming could aggravate allergic hazards and thereby jeopardize public health.
authors.affiliation: Department of Botany and Microbiology, University of Oklahoma, Norman, Oklahoma 73019-0245 USA.
authors.forename: Shiqiang
authors.initials: S
authors.lastname: Wan
authors.forename: Tong
authors.initials: T
authors.lastname: Yuan
authors.forename: Sarah
authors.initials: S
authors.lastname: Bowdish
authors.forename: Linda
authors.initials: L
authors.lastname: Wallace
authors.forename: Scott D
authors.initials: SD
authors.lastname: Russell
authors.forename: Yiqi
authors.initials: Y
authors.lastname: Luo