Date of Award

5-2007

Document Type

Thesis

Degree Name

Master of Science (MS)

Legacy Department

Forest Resources

Advisor

Wang, Geoff G

Abstract

Southeastern coastal plain landscapes are recognized for sharp transitions between upland pine and bottomland hardwoods. The ecotone is characterized by distinct elevational and compositional changes and thought to be, in part, maintained by fire. The goal of this study was to investigate the role of fire in this ecotone by examining differences between burned and unburned ecotones as well as changes from pre- to post-burn conditions on the coastal plain of South Carolina.
Two locations were selected for this study, the Francis Marion National Forest (FMNF) and a nearby private plantation. Vegetation and environmental variables were collected in the summers of 2005 and 2006. Vegetative species presence absence data coupled with environmental variables were used in nonmetric multidimensional scaling (NMS) and revealed compositional differences between locations. These differences are hypothesized to be in part due to the period of prolonged fire absence at the FMNF in the mid 20th century, which may have successfully shifted the vegetative community composition and structure.
Analyses indicated that the ecotone was unpredictable, with some variables being more similar to pine, others more similar to hardwoods, while still others are unique from both adjacent ecosystems. Contrary to prior hypothesis, unique species were not found in the ecotone. Instead NMS ordination indicated the existence of unique plant assemblages and vegetative structure found in the ecotone community type. The dissimilarity of the ecotone to the surrounding communities are likely influenced by several factors including: long-term land history events, recent management practices (including plowed fire lines), and uneven fire behavior occurring within the ecotone.
Short-term burn response was confounded by the time of measurement. When comparing pre- and post-burn years, many significant reductions in cover occurred for both burned and unburned sites, across all the community types at both locations. Most notably, functional group cover (graminoids, forbs, vines, woody) had significant reductions across all treatments. The findings of this study suggest that historical events have persistent effects on current and future vegetation composition and structure.

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