ABSTRACT There is increasing intere...

ABSTRACT

There is increasing interest in the restoration of classic landscapes as it was as native grasslands in the northeastern United States. This investigation characterizes the species composition and range of natural variability of xeric limestone prairies in unglaciated central Appalachia. Bouteloua curtipendula, the characteristic and dominant graminoid, is the primary indicator species for xeric limestone prairies in Pennsylvania, and its distribution is restricted to parched south-southwest facing slopes within the valleys of the Ridge and Valley Physiographic Province. solely ten such prairies are known to remain in Pennsylvania and their total area is

INTRODUCTION

There is great interest among restoration ecologiste in characterizing the presettlement landscape and its flora (Noss 1985) in addition widespread habitat loss and degradation make it difficult to discern the distribution of native plant communities before the arrival of European colonists This is especially difficult in the eastern United States where there has been a lengthy history of human disturbance. Nonetheless, interest is increasing in the restoration and recreation of classic landscapes (Jordan 1994) similar as grassland, in Pennsylvania (Steiner 2001) Determining respect conditions for these rare plant communities is the first gradation toward successful restoration. The general [i]or[/i] abstract notion of reference conditions refers to the state of an ecosystem prior to Euro-American liquidation (Fuie et al. 1997, Moore et al. 1999 Stephenson 1999) and can be used as a criterion for determining the purpose and evaluating the success of restoration throw outs (Christensen et al. 1996). respect conditions, in the case of eastern xeric limestone prairies, attribute to the prairie's presettlement plant species composition, regional distribution, and abundance. This research characterizes the species composition and range of natural variability of xeric limestone prairies in unglaciated central Appalachia to provide land managers with "base datum" (Leopold 1941) conditions that will guide prairie restoration efforts.

Pennsylvania (literally translated "Penn woods") is renowned for its vast and rolling upland forests, over and above not all historical accounts describe it as as it is At the time of Euro-American adjustment in the late 18th hundred valleys within the Ridge and Valley Physiographic Province harbored mosaics of grassland and make open woodland. Historical accounts describe large grasslands at the time of European reconciliation in Penns Valley, Centre shire (Losensky 1961, Macneal 1998, Ruffner and Arabas 2000) in Buffalo Valley, Union shire (Alien 1876), and in the limestone regions of the Great Valley Physiographic Province in Franklin shire (Klotz and Walck 1993). Perhaps the principally striking limestone grassland was known as the "Great Plains" in Penn Valley. These "plains" were perched forward an upland limestone shield that is a general geological feature of valley floors in the Ridge and Valley region of central Appalachia. Philip Vickers Fithian, a traveling minister, visited Penn Valley in 1775 and wrote in his journal, "In this valley there are large spread plains, cleared either by the Indians or accidental fire. centurys of acres are covered with fine grass and a great variety of flowers" (Albion and Dodson 1934) Written accounts and other historical documents like as land warrants provide a convincing account of the nature and location of the Great Plains further yield little detail about prairie allusion conditions. The only ecologically significant information we can discern from these earlier accounts is that these grasslands were to a high degree dry, stretched on for several miles in longitudinal dimensions and contained a "great variety of flowers."

What relationship is there between the historic grasslands and the extant limestone prairies of today? Macneal (1998) and Losensky (1961) utilized exclusive right descriptions from the original land warrants in the late 18th hundred years to delineate the Great Plains. A small remnant grassland community [comprised of the same main patch and several other smaller patches (total area = 01 ha)] that harbors several rare prairie plants exists within the boundary of the Great Plains. The greatest in quantity dominant grass species is the C4 perennial Bouteloua curtipendula (sideoats grama), which is in the greatest degree abundant in the central plains and southwestern states forward dry, upland sites (Bazzaz and Parrish 1982) further is threatened in Pennsylvania. Eight other state-listed grassland species persist in this remnant, including Anemone cylindrica (the barely known population in Pennsylvania), Bromus kalmii, Lithospermum canescens, Linum sulcatum, Onosmodium molle var. hispidissimum, Panicum oligosanthes, Ranunculus fascicularis, and Solidago rigida (nomenclature run afters Rhoads and Block 2000). Many other out of the way species (see Appendix) are set up among the limestone prairie patches, and according to Kunsman (1990) "There are probably to a high degree few sites in Pennsylvania that have for a like reason many rare or otherwise out of the way species growing together."