Establishment of permanent plots and analysis of woody vegetation in the Tennessee River Gorge, Marion and Hamilton Counties, Tennessee

The Tennessee River Gorge (TRG) is a large river canyon 8 km west of Chattanooga, Tennessee, on the Cumberland Plateau. In 1984, the Tennessee Natural Heritage Program (TNHP) described 21 vegetation communities within the TRG. Permanent vegetation plots for the long-term study of 13 of these communities were established in summer 2009 in order to fulfill three goals. The first goal was to provide baseline data for long-term monitoring through establishing and surveying 100 plots. The second goal was to perform a temporal comparison of each community to its original description from 1984. The third goal was performing a comparison of the communities within the current study area. One-hundred 100 m2 circular plots were distributed within the communities based on their relative size in the TRG. All woody species more than 5 cm in diameter at breast height (dbh) within each plot were field identified and recorded. Importance values for the taxa of each community, Sorensen’s similarity index, the Marczewski-Steinhaus (MS) dissimilarity index, as well as a Hutcheson’s t test on the Shannon diversity, were used to compare each community to its original 1984 description. The Sorensen’s, MS, and Sorensen’s Quantitative (SQ) indices were used to compare similarity between the communities of the current study. In addition, cluster analysis and principle coordinates analysis (PCO) were used to compare the distinctiveness of communities of the current study from each other. Plot surveys were completed at the end of summer 2009. Results of the temporal comparison indicated moderate to strong similarity for all but one community to their original descriptions. Comparing the communities of the study area indicated none of the communities had an identical composition with any other community, though different communities tended to be most similar to communities in similar locations in the TRG. Quantitative data gathered in this study provide a baseline for future studies long-term monitoring. These possibilities are beneficial by adding to information gained from previous qualitative studies in the TRG and enabling comparison of future change within the communities of the TRG due to ecological succession or climate change