Gehring, J. L. , Alexander, N.J. .
Population genetic diversity of Gentiana puberulenta in tallgrass prairie fragments.
The North American tallgrass prairie is one of the most endangered ecosystems in North America. Most tallgrass prairie in the American Midwest was destroyed in the 1800s and what little remains occurs primarily as small patches surrounded by agricultural or urban landscapes. Two possible effects of this intense fragmentation are a decrease in population size, potentially leading to genetic drift and inbreeding, and population isolation, causing the decrease or elimination of gene flow and thus exacerbating loss of genetic variation via genetic drift. Fragmentation of the tallgrass prairie was accompanied by a sharp decrease in fire frequency in most remnants for at least 50 to 100 years. Lack of fire in tallgrass prairie causes a myriad of ecological effects, which may further exacerbate loss of genetic diversity. Understanding the consequences of the changes brought about by fragmentation, at least within representative species that embody a broad spectrum of life history, phenology and dispersal, is necessary for the preservation of genetic diversity in remaining tallgrass prairie remnants. We studied a widespread tallgrass prairie species, Gentiana puberulenta, which may have been adversely affected by the absence of wildfire because of its short stature. We determined genetic diversity of two large (>1500 individuals) remnant populations of G. puberulenta in central Illinois using isozymes and RAPDs. The results from both types of genetic markers reveal low levels of polymorphism, indicating that current large population size is not necessarily a good predictor of high genetic diversity in this fragmented system. Possible causes of low genetic diversity in this species include low levels of genetic diversity in the evolutionary lineage, low outcrossing rates, pre-settlement population bottlenecks or a population bottleneck during the period of fire suppression.
1 - Bradley University, Department of Biology, Peoria, Illinois, 61625, USA
2 - National Center for Agricultural Utilization Research, USDA/ARS, MTX Research Unit, Peoria, Illinois, 61604, USA
Presentation Type: Poster
Location: Special Event Center (Cliff Lodge)
Date: Tuesday, August 3rd, 2004
Time: 12:30 PM