Don Cipollini (Committee Member), David Goldstein (Other), Thomas Rooney (Committee Member), James Runkle (Advisor)
Master of Science (MS)
Invasive species have the capability to alter landscapes and change the composition of a forest in a very short time. The recent invasive pest, Agrilus planipennis, emerald ash borer, was unintentionally introduced to the United States via ship route to Michigan. The pest attacks and kills all five native ash species in Ohio. This study focused on an area in west central Ohio not yet affected by the borer. Ash centered plots were used to record all species and sizes (diameter at breast height) within a 5m radius of a central ash tree. Plots ranged in topography and all five ash species were sampled. Moisture contents were calculated for each plot based on topographical variables in ArcGIS. My objectives were to answer the following questions: What species will replace ash and how do replacement species vary among different ashes and with topography? Also, how does the understory composition vary among ash species as related to topography? Results suggest that sugar maple will be the likely successor of ash species. Sugar maple was the most important species in all plots and under all ash species except for the black and pumpkin ash which were associated with hydric species. American elm was highly associated with both white and blue ash. A moisture index (IMI) showed a significant separation of black and pumpkin ash, found in swampy regions, from the other three ashes. Black and pumpkin ashes were found in the wettest sites followed by blue, green, and white ash. Detrended correspondence analysis found the five ash species to segregate in a two-dimensional space based on a moisture gradient. Significant correlations were found between the ordination scores and both the size of the central tree and the nearest neighbor indicating a possible succession gradient as well. Post emerald ash borer trends appear to be toward a forest dominated by maples and possibly elms.
Department or Program
Department of Biological Sciences
Year Degree Awarded
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