Recent Topics Posters
Alerding, Anne B. .
Impact of garlic mustard invasion on plant community structure in coniferous and hardwood forests of Virginia .
The biennial herbaceous plant, garlic mustard (Alliaria petiolata) is quickly spreading through understory communities of northeastern temperate forests. Garlic mustard is known to decrease tree seedling growth and survival in hardwood forests by disrupting belowground mycorrhizal mutualisms but less is known about such processes in softwood forests. We sampled plant communities in adjacent forests dominated by either conifers (Pinus strobus) or hardwoods (Quercus rubra and Liriodendron tulipifera) to determine how common understory species were responding to garlic mustard invasion. We were unable to locate any seedlings or saplings of the dominant overstory tree species, indicating that succession is imminent in both forests. Since Ulmus americana seedlings were present in both understory environments, this tree species may exhibit some degree of resistance to garlic mustard allelochemicals. Overall, both forests exhibited similar levels of species diversity but the relative abundance of shared species differed. Of the nine understory species found in both forests, two are noted invasive plants (Duchesnea indica and Lonicera japonica) and both of these were more abundant in the pine forest understory. This is consistent with the greater abundance of garlic mustard plants found in our plots. Thus, the conifer forest in our study exhibited higher levels of understory invasion compared to the hardwood forest. Correlated with increased invasion we observed 90% fewer individuals of the native species Arisaema triphyllum and Asarum canadense. Surprisingly, abundance of the native species Lindera benzoin, Osmorhiza longistylis, and Stellaria pubera was two to six times greater in the pine forest understory. Results will be discussed in terms of the roles of these species and the structure and function of pine and hardwood forests.
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1 - Virginia Military Institute, Biology, 203 Science Building, Lexington, VA, 24450, USA
Presentation Type: Recent Topics Poster
Location: Event Tent/Cliff Lodge
Date: Tuesday, July 28th, 2009
Time: 5:30 PM