Did tallgrass prairie extend into Pennsylvania?

<p>Researchers, who have suggested that xeric limestone prairies of central Pennsylvania are remnants of the Prairie Peninsula, the extension of prairie vegetation into the eastern forest, did not take into account the considerable differences between limestone prairies and the tallgrass prairies of the Midwest. Mesic tallgrass prairies dominated by <em>Andropogon gerardii</em> found in the Central Lowlands of the Midwest on deep , rich, glaciated soils definitively constitute relicts of the Prairie Peninsula. If the Prairie Peninsula did extend into Pennsylvania, then one would expect to find remnants of mesic tallgrass vegetation. Three prairie-types do exist in Pennsylvania; however, mesic tallgrass prairies are not present. Xeric limestone prairies of central Pennsylvania are very different from tallgrass prairie. They are restricted to the Ridge and Valley Physiographic Province, are found on unglaciated, shallow, rocky, limestone-derived soils, and are dominated by <em>Bouteloua curtipendula</em>. Limestone prairies in the northeastern United States also are found in the Ridge and Valley in West Virginia and in the Interior Low Plateau in Ohio. Though xeric prairies might have been augmented by the post-Wisconsin prairie migration during the Hypsitherrnal Interval, they probably already were present in the Ridge and Valley of Appalachia before the eastward extension of the prairie flora. Furthermore, the calciphile species of xeric limestone prairies probably could not inhabit the mountains of the Appalachian Plateau, a region depauperate of limestone soils. Therefore, according to extant vegetation, the tallgrass prairies of the Prairie Peninsula probably did not extend into Pennsylvania.</p>