Wells Savannah, an Example of a Unique Fire-Dependent Ecosystem in the North Carolina Coastal Plain

savanna;wetland;flora

Shelingoski, Susan ; Thomas R Wentworth, Committee Co-Chair,Jon M Stucky, Committee Co-Chair,Shelingoski, Susan ; Thomas R Wentworth ; Committee Co-Chair ; Jon M Stucky ; Committee Co-Chair

University:North Carolina State University

关键词: savanna;    wetland;    flora;   

Others  :  https://repository.lib.ncsu.edu/bitstream/handle/1840.16/74/etd.pdf?sequence=1&isAllowed=y

美国|英语

来源: null

【 摘 要 】

Wells Savannah is a unique wet pine savanna located in the Lower Coastal Plain of North Carolina.The 47-hectare tract was discovered in 1997 during a North Carolina Natural Heritage Program Natural Areas Inventory of Pender County and subsequently purchased by the North Carolina Coastal Land Trust in April of 2002.It consists of two utility rights-of-way and a fire-suppressed pond pine woodland.Poorly drained, hydric soils with unusually high silt content occur throughout the site.The combination of soil characteristics and plant species composition have not been identified in previous studies of savannas in the region (LeGrand and Sorrie, 1997; Taggart, 1990).The purpose of this study consisted of two main objectives.The first objective was to characterize the soils and to conduct an inventory of the vascular flora at Wells Savannah.The second objective was to locate and gather vegetation and soil data on reference sites in order to perform an ordination of Wells Savannah among similar savanna communities in the Lower Coastal Plain.Reference savannas were located within Holly Shelter Game Land.In addition, one hundred twenty plots were extracted from the North Carolina Vegetation Survey (NCVS) database to be used in our ordinations.The reference savannas located within Holly Shelter Game Land were inventoried during this study in order to facilitate their use as a basis of comparison for the soil and flora inventory, as well as in the ordinations. Soil drainage, texture, and presence of redoximorphic indicators were examined at both Wells Savannah and Holly Shelter Game Land in order to accomplish our first objective.Weighted averaging was then used to formulate a wetland index for Wells Savannah and Holly Shelter Game Land.We identified 219 species in 112 genera and 50 families at Wells Savannah.Seven of the species are listed by the North Carolina Natural Heritage Program as endangered, rare, or of special concern. One is federally listed.Eight community types were identified within Wells Savannah.We found species composition, soil moisture, and soil texture at Wells Savannah to be unique relative to those features of other savannas in the region.Seventy-one percent of the species found at Wells Savannah were obligate or facultative wetland species.Wells Savannah lacked wiregrass (Aristida stricta), a common species found in most savannas in the region, but does support unusually high numbers of Rhynchospora species.As a means of conducting the second portion of our study, we compared plant cover classes with soil chemistry, particle size and geographic location in ten plots at Wells Savannah, six reference plots established in Holly Shelter Game Land, and one hundred twenty plots extracted from the North Carolina Vegetation Survey (NCVS) database.Multivariate analyses were used to evaluate the data.The resulting ordination has provided a visual interpretation of the proximity of Wells Savannah's plant community to the most similar savanna communities occurring within this geographic region.We determined the soil variables and plant species which acted as indicators at several points in the ordination and used the information to identify the savanna community type most like what we found at Wells Savannah.We identified only one NCVS plot that ordinated among our plots at Wells Savannah.The most important environmental variables correlated to plant species composition at Wells Savannah are high levels of iron, silt and clay in the surface layers of the soil.The species composition and soils at Wells Savannah may represent a savanna community thought to be extirpated in the region.