rare plant communities in canaan valley, west virginia

More documents

Recommendations

Info

The plant community type may be common, but it typically supports one or more rare plantspecies. Because of the overall limited area of wetlands in the unglaciated Plateau, one of theprincipal factors used to assess rarity was the occurrence in wetlands.In most instances, the name for a plant community is based on the occurrence ofdominant species in the uppermost plant stratum. Exceptions to this are communities withextensive bryophyte ground cover that are associated with organic soils. To be listed as adominant species, the species had to be: a) cited as a component of a community based onempirically derived data, b) included in a study where stratified sampling occurred using linetransects, intercepts, or quadrats, or c) considered a dominant based on a calculation of someindex of importance, dominance, or occurrence. Although the determination of rarity for plantcommunities is somewhat subjective, we base it on firsthand knowledge of the vegetation of thevalley and adjacent high elevation areas, and a comparison to plant communities reported forother wetlands in the region. Species nomenclature follows Harmon et al. #(2004).Results and DiscussionFortney (1975) described 42 plant communities in Canaan Valley, 32 of which were classified aswetland, and 10 as upland types. All wetland plant community types except for those dominatedby spiraea, glade St. Johnswort, and broad-leaved cattail (Typha latifolia) meet at least one of thethree criteria for rare plant communities, and therefore are considered rare. Two additionalcommunities (Salix Tall Shrub Thicket and Mixed Conifer-Black Ash Swamp Forest) wereadded to the list of rare communities based on recent fieldwork. Four upland communities weredesignated as rare: grass bald communities composed of mixed grass-forb meadows and lowshrub thickets on mountain summits, big-tooth aspen groves, and black cherry groves (See Table1).The relatively high number of wetland versus upland communities is likely related to the highvariation in soil types and hydrologic regimes in wetland areas (Fortney 1997; Fortney andRentch 2003). The vegetation map developed by Fortney (1997) and the soils map for CanaanValley (USDA 1960) support this, showing that upland areas tend to have soil and vegetationunits that are generally larger than those in wetland areas. Further, the juxtaposition of wetlandunits, soil series, and vegetation types, tends to be more complex in terms of variability per unitarea and boundary conditions. The occurrence of rare and otherwise unusual plant communitiesis consistent with this pattern.Upland Plant CommunitiesMixed Grass-Forb Balds and Low Shrub Balds (Fig. 1). Open grassy habitats on mountainsummits were described by early explorers who visited the Canaan Valley region, includingareas within Dolly Sods to the east. It is likely, according to Fortney (1975) that the area coveredby these habitats expanded following the logging era of the late 1800s and early 1900s and thesubsequent fires (Allard and Leonard 1951). Core (1966) and Fortney (1975) described balds asopen, grassy communities often dominated by mountain oat grass. However, Rentch andFortney (1997) concluded that vegetation of these areas had changed since 1975, acquiring morevariability, including an increase in importance of shrubs, forbs, and wrinkled hairgrass. Theyidentified wrinkled-leaf goldenrod, New York fern (Thelypteris noveboracensis), blackberry(Rubus canadensis), upland low blueberry (Vaccinium pallidum), and lowbush blueberry (V.angustifolium) as other common codominant species of these habitats. Rentch and Fortney(1997) further concluded that these areas are maintained in their open state because of climaticfactors, including extreme temperatures, and damage of vegetation by wind, ice, and snow.4
Because of these factors, balds are likely to remain in combinations of grass, forb, and shrubstages for the foreseeable future. These habitats and associated vegetation types are rare on aregional scale, being restricted to only a few areas in the central Appalachian Mountain region.Populus grandidentata Grove Forests. Big tooth aspen groves are chiefly restricted to welldrainedCalvin and Dekalb soils at the bases of surrounding mountain slopes. These aretemporal and early successional communities, and have largely been replaced by encroachingnorthern hardwood forest. The herbaceous stratum is commonly composed of old-fieldgraminoids and forbs, such as wrinkled leaf goldenrod, hay-scented fern, bracken fern, andmountain oat grass. The shrub strata is generally poorly developed or absent.Prunus serotina Grove Forests (Fig. 2). Black cherry was the first species to be commerciallyexploited in the Valley, and several black cherry groves remain near Camp 72 and Big Cove.These communities occur on well-drained areas immediately adjacent to wetlands along thebases of the surrounding mountains. They often occur as pure stands, or with a small componentof red maple. The shrub stratum is often lacking, and herbs are commonly large colonies of NewYork fern and hay-scented fern (Dennstaedtia puntilobula).Wetland Plant CommunitiesFour conifer-dominated or mixed conifer-deciduous communities in Canaan Valley areregionally rare. They can develop on mineral or organic soils and on soils with histic-epipedons(Blago Series). On organic soils, a bryophyte layer of Sphagnum spp. mosses typically will bepresent.Picea-Tsuga-Abies Swamp Forest. Compared to presettlement estimates of total area of thiscommunity type, today mixed conifer swamp forests of spruce, hemlock and balsam fir representa relatively small portion of the current vegetative cover in the valley. Over the past fourdecades, a major portion of this type [as well as subtypes in which red maple and yellow birch(Betula alleghaniensis) are components] has been innundated or degraded by beaver activities.This is particularly apparent within Canaan Valley State Park and Big Cove. Associated canopyspecies include black cherry and mountain holly (Ilex montana).Picea-Tsuga-Abies-Acer-Betula (Fraxinus) Swamp Forest (Fig. 3). We consider this a subtypeof the spruce-fir-hemlock community described above because of its hardwood component,which consists of red maple and yellow birch. It generally occurs in association with otherconifer-dominated communities. Black cherry and mountain holly are occasional components ofthe canopy. An unusual variation of this type has black ash as a principal component of theoverstory. This type, identified along Abe’s Run (Rentch et al. this volume) and the NorthBranch, appears to be associated with limestone. Several rare plants have been located in thiscommunity type, including glade spurge, alder-leaved buckthorn (Rhamnus alnifolia), Jacob’sladder, and showy lady’s slipper (Cypripedium reginae).Picea rubens Swamp Forest. Although not frequent, red spruce can occur as a single dominantcanopy species in a forest community. This type is also often associated with Spruce-Hemlock-Fir Swamp Forest.Abies balsamea Swamp Forest. This forest type is occasional throughout the Valley, where it isassociated with the three previously described forested communities. It usually occurs in smallstands [< 1 ha(2.5 ac)]. Infestations of the balsam woolly adelgid (Adelges piceae) have reducedthe balsam fir overstory component in most coniferous stands, particularly in the central andsouthern portions of the Valley. Between 1983 and 2002, balsam fir was completely extirpatedfrom three stands in which it had been a dominant or codominant component of the overstory(Fortney, unpublished data). In addition, because of deer herbivory of seedlings, there is5
Page 3: (Photinia melanocarpa), and herbs s
Page 7 and 8: species such as small and large cra
Page 9 and 10: streams. Common rush is also a freq
Page 11 and 12: Vogelmann, H. W. 1978. Evaluation o
Page 13 and 14: Table 2. Plant communities cited in
Page 15: Figure 1. Map of Canaan Valley West

rare plant communities in canaan valley, west virginia

Create successful ePaper yourself

Delete template?

Save as template?