Date of Award

January 2011

Degree Type

Open Access Thesis

Degree Name

Master of Science (MS)

Department

Biological Sciences

First Advisor

Charles L. Elliott

Department Affiliation

Biological Sciences

Abstract

Soil, microtopographic, and light parameters associated with federally endangered running buffalo clover (Trifolium stoloniferum) plants on the Blue Grass Army Depot, Richmond, KY, were examined during the 2004 and 2005 growing season. Study samples or measurements were determined at 27 "long-term" sites (plots which have had clover present since 1992-1994), 23 "disappeared" sites (plots which had clover in 1992-1994, but did not have plants present at the time of this study) and 25 random/control sites (randomly selected 1 m2 plots in areas in which running buffalo clover has never been reported).

Average precipitation on the Blue Grass Army Depot was significantly higher in May 2004 and May 2005, as well as June 2004 than in June 2005 (T-calculated= 3.37 and 2.38, respectively). Ambient temperatures at ground level were significantly lower in March 2005 than 2004 (T-calculated= 41.76) and significantly higher in June and July 2005 than 2004, respectively (T-calculated= 22.22 and 15.86, respectively). The average number of running buffalo clover rooted crowns and inflorescences per plot did not differ significantly between years.

Overall, there was no difference between long-term clover sites, disappeared clover sites, or random/control sites in terms of average soil nutrient values for NH4, NO3, Zn ,K, Mg, P, and pH. However, there were significant difference between years for some nutrients, i.e., average Mg (F= 8.77), pH (F= 14.04), and NO3 levels (F= 115.06) were higher in 2004; while mean Ca (F= 11.22), NH4 (F= 116.09), and P (F= 11.21) levels were higher in 2005. Only potassium showed a significant site-by-year interaction (F =3.33), with clover sites having the most potassium for both years, random/control sites were intermediate, and disappeared clover sites had the lowest values.

Plots examined in this study occurred within eight soil texture types and 14 soil series. There were significantly more plots in the silt loam texture type (X2 = 279.27). There was no significant difference in mean bulk density (F= 0.57), percent soil moisture (F= 0.22), soil water content (F= 0.07), volumetric water content (F= 0.09), or porosity (F= 0.56) between long-term clover sites, disappeared clover sites, or random/control sites. Between years, only bulk density (F=4.96) and porosity (F= 4.95) showed a significant difference. Bulk density readings were higher in 2005 than 2004; while porosity was higher in 2004 versus 2005.

There was significantly greater topographic variation of elevation within plots between long-term plots and disappeared clover plots when compared to random plots (F=11.13). When the overall shape of each running buffalo clover study plot was examined across the topographic spectrum, a trend was noted. Long-term clover plots occurred twice as often, compared to random, in a depression; long-term clover plots on mounds occurred three times more frequently than random. In plots in which running buffalo clover has been present since 1992-1994 (long-term sites), clover plants were not randomly distributed with regard to where they were encountered along a microtopographic transect (χ20.05,6 = 12.592) ; indicating microtopographic variation may be important for the establishment and maintenance of running buffalo clover plants. Although not statistically significant, sites with clover (long-term plots), on average, had lower maximum light values than their counterparts.

The information provided in this study can serve as base-line values with which future assessments of running buffalo clover sites on the Blue Grass Army Depot can be made; as well as provide data for comparative purposes at sites across the geographic range of Trifolium stoloniferum.

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