A ten-year monitoring record of the western prairie fringed orchid at Pipestone National Monument Gary D. Willson, Craig C. Young, and F. Adnan Akyuz

Pipestone National Monument Location: SW Minnesota Size: 282 acres

Pipestone National Monument Protect quarries of pipestone used by native Americans from prehistoric times to the present Preserve remnants of tallgrass prairie and Sioux quartzite prairie

Pipestone National Monument Fire history in unit 2 Apr 23, 1973 ?, 1976 May 5, 1983 May 2, 1986 May 2, 1988 May 5, 1990 May 8, 1992 May 4, 1994 May 30, 1997 May 2, 2002

Western Prairie Fringed Orchid Monitoring Objectives –Track changes in number and distribution of flowering plants through time –Track changes in plant height as an indicator of plant vigor and number of flowers per plant as an indicator of reproductive potential

Western Prairie Fringed Orchid Monitoring History –1985 Orchid discovered in unit 2 –1993Monitoring initiated in units 2 and 3 (2 person, random search) –1995Monitoring method revised (4-7 person, systematic search) –2000Monitoring protocol written (4-7 person, systematic search)

Western Prairie Fringed Orchid Monitoring dates 19 July, July, July, July, July, July, July, July, July, July, 2004

Western Prairie Fringed Orchid Monitoring Methods –Systematic search and count –Map locations Laser theodolite (Nikon Total Station) GPS

Western Prairie Fringed Orchid Monitoring Methods –Plant data Measure plant height (stem plus inflorescence) Count no. of flowers including flower buds

No. of Flowering Orchids Burn 5/30 Burn 5/2

Mean Plant Height and Mean No. of Flowers per Plant

Western Prairie Fringed Orchid Monitoring Summary –Large range in no. of flowering plants, 0 (1998) – 221 (2003); possible upward trend in nos. –Population clustered in 2 (low and wet) locations with outliers –Significant difference in mean ht. of plants; no significant difference in no. of flowers per plant –Inconsistent response following Rx fire (burn 30 May, 1997, followed by 3 flowering plants that year and 0 in 1998; in contrast burn 2 May, 2002, followed by 124 flowering plants that year and 221 in 2003) –Inconsistent precipitation response (1997, driest year , followed by 3 flowering plants that year; in contrast 1995 wettest year ) followed by 37 flowering plants that year)