The Vascular Flora and Phytogeographical Analysis of the Tennessee River Gorge, Hamilton and Marion Counties, Tennessee

Abstract

An inventory of the vascular flora of the Tennessee River Gorge (TRG) was conducted between April 2009 and July 2011. The TRG is a 41-km-long river canyon located on the Cumberland Plateau physiographic province within Hamilton and Marion counties, TN. According to prior ecological surveys, the 4970-ha study area contains 12 natural communities. This survey documented 123 families, 392 genera, and 700 species and sub-specific taxa, including 138 county range extensions. Approximately 13% of the flora (92 species) is considered non-native. Fifteen imperiled species were reported, including 3 that are undescribed and 9 not documented in any previous Cumberland Plateau flora. In addition to the floristic component of this work, a phytogeographical analysis was conducted for the TRG and 12 other Cumberland Plateau floras in Tennessee and Kentucky. An important finding of this research was the identification of a biogeographical transition zone, from a higher northern to a higher southern species richness. This biogeographic break was identified in the vicinity of Fentress, Scott, and Morgan counties, TN.