Management of a Population of the Federally Endangered Xyris tennesseensis (Tennessee Yellow-Eyed Grass)


James Mincy Moffett, Jr.

Additional Authors:

Robert S. Boyd,


Sept 2013


ABSTRACT A 3-yr study was conducted to determine effects from cutting shrubs that were shading a population of Xyris tennesseensis Kral inhabiting a calcareous seepage fen of the Ridge and Valley Ecoregion. Shrubs were cut to ground level on small plots and Xyris flowering, ramet numbers (a ramet is defined as a leaf-producing stem) and seedling numbers were monitored during three post-treatment seasons. Floral visitation was also documented to determine if shrub cutting increased the likelihood of floral visits by insects that might pollinate flowers. In addition, the seed bank of the site was described and quantified. Shrub cutting significantly increased flowering of Xyris on the site, but only for the first two seasons: by the third season flowering declined, likely caused by competition from other herbaceous species responding to the increased light levels. Shrub cutting also significantly increased seedling production, but no significant increase in the number of Xyris ramets was found. Floral visits were significantly more frequent to Xyris flowers located on cut plots. There was no Xyris seed bank. We conclude that cutting shrubs can stimulate Xyris reproduction for a short period but that long term management must balance this benefit with the resulting increased competition from other non-Xyris graminoids. Management of the fen should strive for a mosaic of microhabitats with varying degrees of woody vegetative cover and exposed mineral soil.