Vascular flora and gradient analysis of the Natchez Trace Parkway

Vascular plant collections were made on the Natchez Trace Parkway over a 15 month period beginning in August 2004. These collections along with previous work done by the National Park Service (NPS) produced a flora of 750 genera and 2196 species in 167 families. Five collection trips were made so as to include as much of the growing season as possible (August 2004, March, May, July and October 2005). Specimens were collected from 500 sites along the Parkway as well as at 50 quadrat locations. The largest families, by species numbers, are Asteraceae (298 species), Poaceae (236 species), Cyperaceae (148 species), Fabaceae (133 species) and Rosaceae (73 species), which accounted for 40.4% of the flora. A Detrended Correspondence Analysis (DCA) and TWINSPAN analysis were performed on data collected from 49 sites along the length of the Natchez Trace Parkway (NATR). It was found that the major environmental gradient (Axis 1) affecting the species composition of the site was to be the level of disturbance. The sites with high levels of disturbance were characterized as grassland field sites, while those areas with low levels of disturbance were characterized as forested sites. The TWINSPAN analysis produced 29 groupings, of which eight were found to be valid groupings. Through the course of the study, almost 450 new species were added to the current knowledge of the Natchez Trace Parkway by the NPS. In addition, one prospective endangered species was located, which will aid the NPS in future management practices within the park.