2004: Hurricane Impacts on the Herbaceous Ground Layer Vegetation

Jennifer Toy (Biology) Whitman College

On September 18, 2003, Hurricane Isabel caused severe damage in the College Woods at the College of William and Mary. In this study completed during the summer of 2004, we investigated what happened to the composition of the ground layer vegetation (herbaceous and woody) in a mature coastal plain forest after a hurricane created openings in the canopy. We also studied how different any changes in composition of vegetation were in areas highly damaged by hurricane microburst winds versus vegetation in areas only slightly damaged by the hurricane. Twenty sites were established in the highly damaged microburst area and the other twenty were set-up in the less disturbed area. For each species, we recorded the number of individuals, percent cover, examples of regrowth, and examples of deer damage.
We discovered there were sixteen species that appeared in the microburst plots, but which did not appear in the less disturbed plots. Erechtites hieracifolia, Phytolacca americana, and especially Liriodendron tulipifera showed large and rapid growth responses and high fidelity to the microburst plots. We also discovered that certain species previously established in the microburst, specifically Quercus alba, experienced regrowth while the Q. alba in the less disturbed plots did not experience regrowth. We did not observe any signs of mortality. From the data, we can conclude that certain species responded rapidly and dramatically to the increased levels of sunlight after a hurricane creates openings in the canopy. Future studies, using these data as a baseline, will determine how changes in composition affect rates and patterns of succession, and ultimately forest structure.

For additional documentation Jennifer Toy provided a PowerPoint Presentation entitled "Hurricane Impacts on the Herbaceous Ground Layer Vegetation"  provided here in PDF form.