02/27/2008 Env Bd Packet - Laserfiche WebLink

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The soils in Mesic Prairie are predominantly mollisols with thick, dark mineral surface layers that have high base saturation and dominantly bivalent cations. They range in texture and drainage from silty and somewhat poorly drained to sandy and somewhat excessively drained, with moderately well - drained to well - drained, loamy soils being most common. Mesic Prairie grades into Wet Prairie on moister sites and into the Hill and Sand- Gravel subtypes of Dry Prairie on drier sites. Separation of Mesic Prairie from other prairie types is based primarily on landform or substrate characteristics rather than on species composition, as floristic boundaries between Mesic Prairie and other prairie types are not well defined. A comprehensive plant species list for Foxborough's Mesic Prairie restoration areas is provided in Appendix B of this report. Dry Prairie Dry Prairies are upland grasslands dominated by prairie species, with <10% tree cover and <50% shrub cover, where the substrate is composed of sand or gravel (sometimes with a thin organic surface layer), or any texture on steep slopes. (Some examples may occur on sandy soils in temporarily flooded areas). Dry Prairie is a type of Upland Prairie, which occurs primarily in the prairie zone, with scattered occurrences in the deciduous forest - woodland zone. These communities are dominated by grasses. The tall grasses, big bluestem (Andropogon gerardii) and Indiangrass (Sorghastrum nutans), are the major dominants on moist sites. Prairie dropseed (Sporobolus heterolepis) is common on both dry and moist sites. Forbs typically are abundant (but subdominant to the grasses) and may have high local diversity. Forb species composition varies with site moisture, although some forb species occur on almost all sites, moist or dry. Several low shrub or sub -shrub species are common on Upland Prairie; the most characteristic is leadplant (Amorpha canescens). Taller brush and trees are absent or scattered, however brush or woodland areas may be interspersed with prairie, usually in association with topographic and aquatic features that provide protection from fire. The most important cause of variation in species composition in prairie communities is variation in soil moisture. The local soil moisture regime is determined by slope, aspect, proximity to the water table, and soil texture. On a regional scale, variation in species composition is primarily caused by climatic variation (i.e., the westward decline in precipitation and northward decline in temperature in Minnesota). Upland Prairies occur on a range of landforms in the prairie zone, from nearly flat glacial lakeplains to steep morainic slopes. In the deciduous forest - woodland zone, prairies occur on droughty, level outwash areas and steep south - and west - facing slopes. The pre - European settlement distribution of prairie was related to the interaction of local fire frequency with growth rates of woody species: where conditions were favorable for rapid growth, more frequent fires were necessary to maintain prairie over savanna, woodland, or forest. Fragmentation of Upland Prairie since European settlement has reduced fire frequency throughout the prairie and deciduous forest - woodland zones, and most prairie remnants have more brush and trees than were present in the past. Dry Prairie is a dry to dry-mesic herbaceous community dominated by grasses and sedges. It occurs throughout the prairie zone and sporadically in the deciduous forest - woodland zone. Dry Prairie has considerable variation in species composition, reflecting interactions among Foxborough Conservation Development Restoration and Management Plan 21