James Amon (Committee Member), Thomas Rooney (Committee Member), James Runkle (Advisor)
Master of Science (MS)
My study was conducted to understand tree community structure and how soil moisture and fire frequency influence them. Eighteen plots were placed in the Edge of Appalachia Nature Preserve of unglaciated southern Ohio: nine within a prescribed burn site and nine control sites outside the burn. Sites were stratified in triplicate across GIS-derived integrated soil moisture index (IMI) classes. Burning was done in 1996. Overstory species dbh and sapling species were sampled 1997, 2001, and 2008. Overstory stems were located in 2009 using range finders. Stem locations were loaded into GIS using novel techniques to quantify individual stem IMI values.
Nonmetric multi-dimensional scaling identified greater heterogeneity among intermediate and mesic sites than xeric sites. Multi-response permutation procedures did not detect community differences between burned and unburned sites, but did detect strong (A=0.3 to 0.2, T=-3.6 to -4.1) distinct community differences that were statistically significant (P < 0.05) among xeric, intermediate, and mesic IMI classes. Analysis of variance identified significant initial effects of burning on Carya saplings and overstory Sassafras albidum stems, as well as lasting effects significant on Carpinus caroliniana.
ANOVA detected significant differences across all sampling years in sapling relative number for Acer rubrum, Sassafras albidum, and Carpinus caroliniana saplings, as well as Quercus prinus, and Liriodendron tulipifera overstory stems between IMI classes. Bonferroni adjusted Kolmogorov-Smirnov tests were used to identify and quantify IMI habitat restrictions of species. Quercus prinus dominated xeric sites (IMI quartiles 18-24), Carya occupied intermediate sites (IMI quartiles 22-44), Acer saccharum occupied intermediate to mesic sites (IMI quartiles 33-44), Sassafras albidum (IMI quartiles 20-40, IMI median 43) and Liriodendron tulipifera (IMI quartiles 39-45) were restricted to mesic sites. My results suggest that greater than one prescribed burn is needed to influence tree community structure; however, some species can be affected by a single burn. Tree communities within a continuous forest region appear to segregate along an IMI gradient. Xeric regions present greater homogeneity than intermediate or mesic regions. However, my results also suggest that specialization does not occur just at the extremes of the gradient, but also in intermediate sites. This finding presents interesting avenues for future research of potential species-specific landscape genetic structures that would be reflective of moisture regimes within a continuous forest. One other possible future application is the use of these novel techniques to resolve and quantify environmental and spatial variables for individual stem with a high degree of accuracy in other study systems.
Department or Program
Department of Biological Sciences
Year Degree Awarded
Copyright 2011, some rights reserved. My ETD may be copied and distributed only for non-commercial purposes and may not be modified. All use must give me credit as the original author.
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