In this Maryland study to simulate deer browsing, Whigham quantified the temporal effects of annual experimental defoliation on the growth rate of leaves and belowground corms, on senescence of corms, and on asexual reproduction. Plants that were 100% defoliated had significantly smaller leaves the following growing season, than did plants in the other two groups. The year effect was not significant for the 50% defoliation and control groups. Biomass of new corms at both defoliation levels decreased significantly after one defoliation. By the end of the third growing season, the mean biomass of new corms in the 50% defoliation group was 48% less than that in the control group. The mean biomass of new corms in the 100% defoliation group was only 16% compared to the control in the third year of the experiment. The study demonstrates that belowground corms are the first biomass component to be negatively impacted by complete and partial defoliation. Reductions in corm biomass, resulting from leaf herbivory, would eventually reduce leaf biomass and sexual reproduction.
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