Date of Award
Master of Environmental Studies (MES)
The Tolleston Strandplain at the southern end of Lake Michigan offers a unique “dune and swale” topography supporting oak savannas on the dunes and a mosaic of wetland communities in the swales. Following years of human degradation, the sites in this area are now being restored. In this effort, assessments of vegetative quality in these sites have been necessary for proper management decisions. However, it is poorly understood what indices best reflect the vegetative quality of these oak savannas and wetlands. A potential method for determining the best indices for these community types is to use benchmarks that employ expert best professional judgment (BPJ). In order to confirm the viability of BPJ for creating benchmarks, Kappa analysis was used to determine the level of agreement among seven experts. They placed each of 63 transects from this unique landscape into one of four quality categories: 1) “good to very good,” 2) “medium,” 3) “poor,” and 4) “very poor.” Discriminant analysis was used to determine the means and weights of the assessment metrics used by each expert. The experts had poor agreement when assessing the oak savannas and fair agreement when assessing the swales. The use of BPJ for creating benchmarks may be in question, but the means and weights of their metrics indicated important parameters that must be considered when creating benchmarks for this ecoregion. Using discriminant analysis, follow-up questions, and a comparison of each expert’s quality categories with remnant oak savanna metrics, biases also were discovered which may have influenced the experts’ assessments of the sites.
Gordon, Brad, "Using Best Professional Judgment to Create Biological Benchmarks for Habitat Assessment of Wetlands and Oak Savannas in Northwestern Indiana" (2013). Master of Environmental Science Theses. 9.