Date of Award
Master of Science in Coastal Marine and Wetland Studies
Coastal and Marine Systems Science
College of Science
Kevin S. Godwin
James O. Luken
Sharon L. Gilman
The recognition of the importance of ecosystem services and the use of reference wetlands as a tool for functional assessment has been institutionalized through the hydrogeomorphic (HGM) approach (i.e., geomorphic setting, water source, and hydrodynamics). These criteria encompass the essential characteristics of the wetland through the use of functional indices and are purported to assess wetland performance, guide restoration, prioritize conservation, and serve as a mitigation tool. The HGM approach is a rigorous process to identify critical wetland functions and functional assessment indices and commonly involves numerous "experts," followed by extensive field study and refinement prior to implementation, often at extreme monetary and labor costs. The overall goal of this study was to assess the application and transfer of an existing HGM functional assessment model to pond cypress depressions of the SC coastal plain examining the general utility of the HGM process, the statistical comparison of the functional capacity indices and the field data between these wetland systems, and the subsequent refinement and calibration of the HGM model to serve as a regional guidebook for SC. Results indicate that the original HGM guidebook reference standard and impacted wetlands vary significantly by Functional Capacity Index (i.e., all eight functions differ) and sub-index variables (17 of 22 statistically different at p<0.05) affirming the HGM concept. Comparison of FCI level between the reference standard wetlands of both systems (i.e., low gradient blackwater riverine and pond cypress depression) indicated that five of eight functions were equivalent while three functions (i.e., provide habitat for wildlife, maintain characteristic plant community, and remove and sequester elements and compounds) required refinement prior to implementation. When assessed at the sub-index level, 16 (of 22) values were not significantly different between the reference standard conditions suggesting that HGM model transference was appropriate. Functional indices and specific sub-index variables were refined and calibrated resulting in a HGM functional assessment model for pond cypress depressions. With independent validation this research provides evidence that the efficient transference of HGM functional assessment is possible, potentially increasing wetland protection efforts.
Blakeney, Sean A., "Application of a Hydrogeomorphic (HGM) Functional Assessment Outside the Designated Regional Subclass: An Estimation of HGM Transference for Pond Cypress Depressions of South Carolina" (2010). Electronic Theses and Dissertations. 65.