Prairie Bushclover (Lespedeza leptostachya)

Currently at Chicago Botanic Garden, genetic analysis using ISSRs (intersimple sequence repeats) is being performed to determine the genetic diversity of the population at Nachusa.

Endemic to the tallgrass prairie region of the upper Mississippi Valley and rare throughout its 4-state range. There are about 32 extant populations, and many of these are small (<150 stems). Populations are restricted to remnants of the prairie that have persisted amid widespread conversion to cropland. Some of the limited amount of remaining habitat is threatened by agricultural expansion, herbicides, urbanization, and the lack of natural disturbances, especially fire.

Herbivory by both small mammals and insects negatively affects seed reproduction (Bowles and Bell 1999). Agricultural activities, residential development, quarry mining, and vegetation management of right-of-ways are also threats. An apparent lack of

Presently known from 36 sites in 24 counties in 4 states-- northern IL, southern and western WI, and southern MN and IA. (Smith et al. 1988) The thirteen populations in IL contain only 249 plants.

Genetic analysis (using allozymes) of populations in Illinois, Iowa, Minnesota and Wisconsin revealed that there is little genetic difference between and among populations (Cole and Biesboer 1992). Currently at Chicago Botanic Garden, genetic analysis using ISSRs (intersimple sequence repeats) is being performed to determine the genetic diversity of the population at Nachusa. Chicago Botanic Garden has seeds of this plant in storage. A joint research effort between the Illinois Department of Natural Resources, Chicago Botanic Garden and The Nature Conservancy of Illinois is attempting to quantify the effects of light periodic grazing on the long-term survival and reproductive recruitment of this species. It is thought that, because this species evolved in the presence of grazing by bison, slight grazing may be necessary to maintain healthy, viable populations.

Light to moderate periodic grazing is believed to favor Lespedeza leptostachya by decreasing the competitive ability of neighboring plants. Prescribed fire without periodic grazing is believed to increase plant competition, an outcome that can be detrimental to Lespedeza leptostachya.

Further research assessing the response of Lespedeza leptostachya to a combination management scheme of fire with light periodic grazing is needed. Understanding the population dynamics that affect seed production and seedling recruitment would be useful for managing populations. Determine whether or not hybrids are forming between Lespedeza capitata and L. leptostachya.

Continued research investigating the genetic diversity of existing populations is needed. Protocols for seed germination and growth need to be established.