Smith, Marian , Wells, Genneth .
Life History of Astragalus crassicarpus var. trichocalyx in Illinois.
ASTRAGALUS crassicarpus var. trichocalyx is listed as endangered in Illinois, where it is restricted to small glacial drift prairies, which are rare in the state. Little is known about the life history requirements of the species or the ecological factors that limits its distribution in IL. The objective of our study was to provide basic biological and ecological information that can be used to formulate conservation plans for the species. In May 2004, data were collected at Beaver Dam State Park (BDSP) and Humphries Prairie (HP), in Macoupin County, IL, to quantify the following characters: population size; soil seed bank; stem number and length; number of fully developed and aborted inflorescences per plant; number of flowers and aborted flowers per inflorescence; and number and size of fruits and seeds per plant. Soil seed bank at both sites was negligible (2 viable seeds from 126, 1.75 X 8 cm cores). Data analysis indicated that although the number of stems per plant was equal at the two sites, and plant stems at BDSP were longer, there were significantly more inflorescences per plant, more flowers per inflorescence, higher fruit set and fewer aborted flowers and inflorescences at HP than at BDSP. Results of this study suggest that although the population at BDSP may be in greater danger of imminent extinction, both populations have extremely limited resources for regeneration from seed. If populations are to persist at these sites, management, including the introduction of seeds and plants, may be necessary.
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1 - Southern Illinois University, Department of Biological Sciences, Box 1651, Edwardsville, Illinois, 62026-1651, USA
Presentation Type: Oral Paper:Papers for Topics
Date: Tuesday, August 1st, 2006
Time: 1:45 PM