Southeastern Naturalist J.S. Rentch, R.H. Fortney, J.T. Anderson, and W.N. Grafton 2015 Vol. 14, Special Issue 7 136 Canaan Valley & Environs 2015 Southeastern Naturalist 14(Special Issue 7):136–157 Plant Communities of Abes Run Wetland, Canaan Valley State Park, West Virginia James S. Rentch1,*, Ronald H. Fortney2, 3, James T. Anderson1, and William N. Grafton1,3 Abstract - Abes Run wetland is a biologically diverse, 82-ac (33-ha) complex of wet meadow, marsh, scrub-shrub, and forested-swamp communities in Canaan Valley, WV. In 2002, we sampled the vegetation in six 65-ft (20-m)-wide transects and identified a total of 179 vascular plant species. We classified 23 species as introduced; 38 occurred at or near the southernmost known limit of their range. Two graminoid-dominated (e.g., Carex spp. [sedges], Leersia spp. [cutgrass], and Scirpus spp. [bulrush]) and forb-dominated (Euthamia spp. [goldenrods]) transects occurred in an area that had been forested and later inundated by Castor canadensis (North American Beaver) in the 1970s. Four transects were mixed-deciduous and coniferous forested-swamp communities. With the exception of transect 5, these sites had an organic horizon that was 32–40-in (80–100-cm) deep in the center, and the water table tended to persist at the wetland surface through the first half of the growing season. The tree stratum was well-developed, although discontinuous, and was dominated by mixtures of Fraxinus nigra (Black Ash), Abies balsamea (Balsam Fir), Picea rubens (Red Spruce), and Betula alleghaniensis (Yellow Birch). A rich shrub layer of Rhamnus alnifolia (Alder-leaved Buckthorn), Ilex verticillata (Winterberry), and Alnus incana ssp. rugosa (Speckled Alder) was also present. The broken overstory created a variable light regime on the wetland floor and as a consequence, there was high diversity of herbaceous plants. Although a rank comparison of 1945 vs. 1997 vegetative-cover classes did not yield any significant differences, we noted 3 trends: 1) North American Beaver activities reduced the area of coniferous swamp forests, 2) wet-graminoid areas increased as beaver dams were abandoned and their impoundments dried, and 3) the extent of scrub-shrub communities increased, particularly in the upper portions of the wetland’s drainage. Introduction Canaan Valley (hereafter, the Valley), in northeastern West Virginia, contains one of the largest inland freshwater wetland complexes in the eastern US. Because of a unique combination of human and natural disturbances, surficial geomorphology, cool climate, frost-pocket effect, and the juxtaposition of upland and wetland habitats, the Valley’s diverse wetlands provide habitats for a large number of rare plant species and rare plant communities (Allard and Leonard 1952, Fortney 1993, Fortney and Rentch 2003, Fortney et al. 2015 [this issue]). Notable among them is the wetland associated with Abes Run in Canaan Valley State Park. This is an 82-ac (33-ha) complex that includes marsh, wet meadow, 1Division of Forestry and Natural Resources, West Virginia University, PO Box 6125 Morgantown, WV 26506-6125. 2Department of Civil and Environmental Engineering, West Virginia University, PO Box 6103, Morgantown, WV 26506-6103. 3Deceased. *Corresponding author - jrentch2@wvu.edu. Southeastern Naturalist J.S. Rentch, R.H. Fortney, J.T. Anderson, and W.N. Grafton 2015 Vol. 14, Special Issue 7 137 scrub-shrub, and forested-swamp communities. Among the rare plants that have been previously found there are Euphorbia purpurea (Glade Spurge), Polemonium van-bruntiae (Jacob’s Ladder), Cypredium reginae (Showy Lady’s Slipper), Rhamnus alnifolia (Alder-leaved Buckthorn), Viburnum opulus var. americanum (Highbush Cranberry), and Abies balsamea (Balsam Fir) (Harmon et al. 2006). In December 2001, we initiated a comprehensive study of the soils, hydrology, and vegetation of Abes Run wetland. This site offered advantages for our study. The wetland and its surrounding watershed are relatively small and well-defined, and comprehensive sampling and monitoring activities were feasible and not hampered by problems of scale. In addition, the wetland lies in a state park, so the site is protected and relatively accessible. The objectives of this paper were to (1) report on the results of hydrology, soils, and vegetation sampling in Abes Run, and (2) identify trends in the development of vegetation in the post-loggingera in the watershed. Study Area Abes Run wetland is part of a small, 370-ac (150-ha) watershed in the southern end of Canaan Valley State Park (Fig. 1). In 1997, the total wetland area, defined by aerial imagery of vegetation (Fortney and Rentch 2003), was ~82 ac (33 ha). The general aspect of the watershed is north-facing, and its total relief is approximately 1228 ft (374 m) from the crest of Cabin Mountain (4528 ft [1372 m]) on the south, to the confluence of Abes Run and Mill Run (3300 ft [1006 m]). Relief of the wetland portion of the watershed is ~16 ft (5 m) over 2625 ft (800 m) of distance. Abes Run is bordered primarily by open fields, mowed meadows, and upland mixed-deciduous–conifer forests. An access road to the state park forms the downstream (northern) boundary of the study area. The Valley’s climate is moderate to extreme, with long, cold, snowy winters, cool to moderate summers, and a short growing season. The average freeze-free period is 90 days (Loche and Beverage 1967), and frost may occur during any month of the year. Mean January and July temperatures are 25.7 ºF (–3.5 ºC) and 65.6 ºF (18.7 ºC), respectively. Annual precipitation averages 55 in (127.2 cm), with much of this falling as snow (123 in [312 cm]) (NCDC 2003). A distinguishing climatic feature is the frost-pocket effect, which depresses nighttime temperatures on the Valley’s floor. Methods Groundwater sampling During the winter of 2001, we installed twenty-one 2-in (5-cm) PVC groundwater-monitoring wells along 6 transects in Abes Run. Transects extended perpendicular to the direction of stream flow from the edge of the upland forested community across the wetland to the upland forest edge. The number of wells installed in each transect varied with transect length, ranging from 2 to 5, in transects 5 and 4, respectively. We placed the bases of the wells at the top Southeastern Naturalist J.S. Rentch, R.H. Fortney, J.T. Anderson, and W.N. Grafton 2015 Vol. 14, Special Issue 7 138 of the low-conductivity clay layer that lay beneath the wetland; average well depth was 34 in (86 cm), and the average screen interval was 22 in (55 cm). Between 21 December 2001 and 12 August 2002, we measured depth to the water table twice monthly using a Solinst Mini 101® (Solinst Canada Ltd., Georgetown, ON, Canada) water-level meter. In this paper, we present the results from the center well of each transect for only one growing season (1 May–September). We also report percent days of continuous standing water and saturation within 12 in (30 cm) of the surface. Soil sampling J. Gorman of the Department of Plant and Soil Sciences at West Virginia University, Morgantown, WV, sampled soils during July 2002. He extracted samples with a Dutch auger to a depth of 39 in (100 cm) at the center of each transect and at the two forest–wetland boundaries. Using his samples, we described soil horizons by texture, depth, matrix color, and redox concentrations. We determined texture by the feel method and color by Munsell soil color charts. For the transect-center sampling points, we report only depth of organic and mineral horizons. Vegetation sampling In July 2002, we conducted vegetation sampling along 6 belt transects (Fig. 1). Transects were 66 ft (20 m) wide and ranged from 213 to 427 ft (65 to 130 m) long. We permanently marked all transect centers with a steel pin. Within each transect, we determined composition and structure of the vegetation using the following methods. For trees (diameter breast height [dbh] > 3.9 in [10 cm]), small trees (1 in [2.5 cm] < dbh < 3.9 in [10 cm]), and saplings (dbh < 1 in, [2.5 cm], height > 3.3 ft (1 m]), we conducted a 100% tally by species and size class. For shrubs and tall tree seedlings (height > 3.3 ft [1 m]), we tallied stems by species every 33 ft (10 m) along the centerline in 16.4 ft x 16.4 ft (5 m x 5 m) subplots. For herbaceous plant species, we estimated percent cover in 3.3 ft. x 3.3 ft (1 m x 1 m) subplots sited at 16.4-ft (5-m) intervals along the centerline. We estimated cover value using a cover-class rating scale (Daubenmire 1968). We also compiled a list of additional species observed during a walk-around within the belt transect but outside the sample subplots. We conducted an additional walk-through on 30 August 2002 to identify plants that we had not tallied during the July sampling. We used field data to calculate basal area and density values separately for the tree and small tree categories. We calculated only density values for saplings, seedlings, and shrubs and determined average cover and frequency for herbaceous plants. We calculated species importance-value (IV) indices for trees and small trees as one-half the sum of relative basal area and relative density, and for herbaceous plants as one-half the sum of relative cover and relative frequency. Species diversity (H') and evenness (E) indices were computed using PC-ORD software (Ver. 4.0, McCune and Mefford 1999). Southeastern Naturalist J.S. Rentch, R.H. Fortney, J.T. Anderson, and W.N. Grafton 2015 Vol. 14, Special Issue 7 139 We classified all species of vascular plants as either native or introduced, using a checklist by Harmon et al. (2006). From all plants identified and collected, we determined those at the northern or southern extent of their ranges using Core (1966), Fortney (1975), Strausbaugh and Core (1977), Gleason and Cronquist (1991), and Pitillo (1994). Nomenclature for vascular plant species followed Harmon et al. (2006). We collected bryophyte specimens during a walkthrough of each belt transect in the winter of 2001, and S.M. Studlar of the Department of Biology, West Virginia University, Morgantown, WV, identified them. Nomenclature of bryophytes followed Studlar et al. (2002). Species scientific names and authorities, as well as common names, are provided in Tables 1–5. We assessed the conservation value of each transect using a floristic qualityindex (FQI) technique adapted for West Virginia’s wetlands (Rentch and Anderson 2006). This method assigns each species a coefficient of conservatism value (C) Figure 1. Vegetation-cover classes and approximate locations of 6 belt-transects in Abes Run wetland, Canaan Valley State Park, WV. Cover classifications follow Cowardin et al. (1979). PSS1 = palustrine, scrub-shrub, broad-leaf deciduous; PEM = palustrine, emergent, persistant; and PFO = palustrine, forested. Southeastern Naturalist J.S. Rentch, R.H. Fortney, J.T. Anderson, and W.N. Grafton 2015 Vol. 14, Special Issue 7 140 ranging from 0 to 10 based on the species’ tolerance to disturbance and habitat degradation, as well as fidelity to specific habitats. Default values for exotic species were 0; species with high C values were generally less tolerant of habitat degradation and found in fewer higher-quality sites. We calculated mean C as: Mean C = Σ (C1 + C2 + C3 +….. Cn) / N, where C is the coefficient of conservatism for each native taxon and N is the total number of native species inventoried. We then calculated FQI as follows: FQI = Mean C / N0.5. In this equation, we included all of the species we tallied in the sample plots, but not species recorded in the walk-arounds. In order to determine year of establishment, we extracted increment cores from several dominant or co-dominant trees within each belt transect. Age determinations of shrubs, such as Alnus incana ssp. rugosa (Speckled Alder), and smaller saplings, e.g., Picea rubens (Red Spruce), were made using stem cross-sections. We sampled at least 2 individuals of each co-dominant species, which yielded a total of 42 sample chronologies. We prepared sample cores and cross-sections using standard dendrochronological techniques as outlined by Stokes and Smiley (1968) and cross-dated samples by matching unique patterns of narrow and wide rings. Annual rings were counted using a Leica (Buffalo Grove, IL) binocular microscope. Historic vegetation changes We identified 52-year successional trends by preparing two geographic information system (GIS) maps showing whole-watershed vegetation cover classes based on interpretation of 1945 and 1997 aerial photographic coverages. Sources and specifications for the aerial imagery were: (1) August 1945, US Department of Agriculture black and white panchromatic prints, scale = 1:20,000; and (2) November 1997, US Geologic Survey, National Aerial Photography Program (NAPP), color-infrared, scale = 1:40,000. We produced raster-image files by digitally scanning the 1945 aerial photographs and importing the files into ArcView 3.2 for use as tracing layers in a heads-up digitization. We used digital elevation-quadrangle (DEQQ) files of Blackwater Falls 7.5-minute quadrangle maps, which covered the Valley, to register the 1945 photograph and identified common landmarks on 1992 EPA Environmental Photographic Interpretation Center (EPIC) land-cover, road, and stream GIS maps (USEPA 1992). The NAPP imagery had already been registered and ortho-rectified. In general, we used the central portions of the photographs for mapping. To compensate for photographic distortions, we used a GIS warping function. We based our 1997 map on an updated EPIC (USEPA 1992) cover-class map of the Valley. Using ArcView 3.2, we projected the EPIC cover-class map over the NAPP images and modified it based on both the vegetation signature of 1997 images and on our ground-truthing. The 1945 map is an original GIS vector file based on an interpretation of the USDA 1945 photography. Additional Southeastern Naturalist J.S. Rentch, R.H. Fortney, J.T. Anderson, and W.N. Grafton 2015 Vol. 14, Special Issue 7 141 details about the preparation of GIS maps and analyses of changes in vegetative cover classes may be found in Fortney and Rentch (2003). We classified upland vegetation in the watershed using the EPIC classification system (USEPA 1992); wetland vegetation was classified using Cowardin et al. (1979). Cowardin classifications were used for analyses and discussion. We evaluated changes in land-cover classification between 1945 and 1997 by comparing cover-type ranks using the Kruskall-Wallis test (α = 0.05). Results We identified a total of 179 vascular plant and 27 bryophyte species along the 6 belt transects. Of the vascular plant species, 145 were herbaceous, i.e., grasses, sedges, forbs, and ferns (Tables 1, 2), and 34 were woody, i.e, trees, small trees, shrubs, and woody vines (Tables 3, 4). Grasses and sedges comprised the most abundant group, with 46 species, and Carex was the most diverse genus with 18 species. In the herbaceous stratum, 5 species occurred in all six transects: Carex gynandra (Nodding Sedge), Dryopteris intermedia (Intermediate Fern), Glyceria striata (Fowl Mannagrass), Polygonum sagittatum (Tearthumb), and Packera aurea (Golden Ragwort). Thirty-five species occurred in only one transect. We identified 24 moss and 4 liverwort species in our bryophyte collection (Table 5). Harmon et al. (2006) classified 21 of the plant species we collected as exotic. Of the exotics that occurred in sample subplots, most occurred only once; their average herbaceous cover value was 1.0% and average importance value was 2.1. Anthoxanthum odoratum (Sweet Vernal Grass) was the most common herbaceous exotic, occurring in 5 transects with a maximum IV of 6.3. Rosa multiflora (Multiflora Rose) occurred in 2 transects, and Elaeagnus umbellata (Autumn Olive) was noted once. Although the potential for replacement of native species by exotics appeared greater in the shrub stratum, one exception to this trend was a large population of Iris pseudoacorus (Yellow Iris) in the lower portion of Abes Run slightly out of the study area and north of the park access road. No introduced species were noted in the tree, small tree, or sapling strata. Of the total 179 species recorded, 38 occurred at or near the southernmost known limit of their natural range. Notable examples were Balsam Fir, Dryopteris cristata (Crested Shield Fern), Equisetum sylvaticum (Woodland Horsetail), Eriophorum virginicum (Cotton-grass), Jacob’s Ladder, Saxifraga pensylvanica (Swamp Saxifrage), and Glyceria canadensis (Rattlesnake Manna Grass). The study area is also the northernmost known location for Glade Spurge. Transect 1 The vegetation on transect 1 had a Cowardin classification of palustrine emergent persistent (PEM1) and was a graminoid-dominated community in an area that had been an active beaver pond in the 1970s. Soils in the center of this transect showed no measurable organic horizon (O); depth to the top of a Southeastern Naturalist J.S. Rentch, R.H. Fortney, J.T. Anderson, and W.N. Grafton 2015 Vol. 14, Special Issue 7 142 Table 1. Importance values (IV, max = 100) for herbaceous species in 6 transects, Abes Run, Canaan Valley State Park, WV, 2002. * = species at or near the southernmost limit of their range, ** = introduced species. Species Common name T1 T2 T3 T4 T5 T6 Achillea millifolium L. var. occidentalis DC** Yarrow 0.2 Agrostis gigantea Roth** Redtop 5.2 4.3 0.8 3.4 1.4 Agrostis hyemalis (Walt.) B.S.P. Hairgrass 0.5 0.3 Anthoxanthum odoratum L. ssp. odoratum** Sweet Vernal Grass 5.8 6.3 0.9 0.5 1.6 Arisaema triphyllum (L.) Schott ssp. stewardsonii (Britt.) Huttleston Bog Jack-in-the-Pulpit 2.7 1.6 0.5 0.9 Asclepia incarnata L. ssp. pulchra (Ehrh. Ex Willd.) Woods Swamp Milkweed 0.9 Asclepias syriaca L. Common Milkweed 1.8 Athyrium felix-femina (L.) Mertens var. angustum (Willd.) G. Lawson* Northeastern Lady Fern 0.7 Brachyelytrum erectum (Schreb. ex Spreng.) Beauv. Northern Shorthusk 0.0 0.5 0.7 Bromus kalmii Gray Canada Bromegrass 0.5 Caltha palustris L. var. palustris* Swamp Marigold 10.1 13.2 5.7 7.4 Cardamine diphylla (Michx.) Wood* Two-leaved Toothwort 0.9 Carex atlantica L. Bailey ssp. atlantica Prickly Bog Sedge 16.8 2.3 2.6 5.3 0.6 Carex baileyi Britt* Bailey’s Sedge 0.3 0.5 Carex bromoides Schkuhr ex Willd. ssp. bromoides* Brome-like Sedge 2.3 3.2 6.5 0.3 Carex cristatella Britton Crested Sedge 0.5 Carex debilis Michx. var. debilis White-edge Sedge 0.9 Carex gynandra Schwein. Nodding Sedge 3.2 3.3 0.4 1.9 6.2 3.5 Carex intumescens Rudge Great Bladder Sedge 1.4 0.3 Carex laxiculmis Schwein. var. laxiculmis Spreading Sedge 0.9 0.7 Carex leptalea Wahl. ssp. leptalea* Bristly-stalk Sedge 0.9 1.8 1.3 1.9 1.4 Carex lurida Wahl. Sallow Sedge 1.7 2.9 0.3 Carex prasina Wahl. Drooping Sedge 2.7 1.0 3.9 3.7 Carex scoparia Schkuhr ex Willd. var. scoparia Pointed Broom Sedge 4.1 1.0 Carex stipata Muhl. Ex Willd. var. stipata Stalk-grain Sedge 1.4 0.4 0.5 0.5 Carex trisperma Dewey var. trisperma* Three-seeded Sedge 1.0 0.4 Carex vulpinoidea Michx. Foxtail Sedge 0.6 0.5 Chelone glabra L. Turtlehead 1.3 0.5 1.6 Chrysoplenium americanum Schwein. ex Hook.* Golden Saxifrage 2.2 0.5 1.4 Cirsium muticum Michx.* Swamp Thistle 0.5 Clematis virginiana L. Virgin’s Bower 0.9 0.5 1.9 2.6 Dennstaedtia punctilobula (Michx.) Moore Hay-scented Fern 10.8 0.5 Southeastern Naturalist J.S. Rentch, R.H. Fortney, J.T. Anderson, and W.N. Grafton 2015 Vol. 14, Special Issue 7 143 Table 1, continued. Species Common name T1 T2 T3 T4 T5 T6 Doellingeria umbellata (P. Mill.) Nees* Flat-top Aster 0.6 0.3 0.5 0.9 Dryopteris carthusiana (Vill.) H.P. Fuchs Log Fern 2.3 0.9 0.4 Dryopteris cristata (L.) Gray* Crested Shield Fern 3.2 0.7 Dryopteris intermedia (Michx. ex Willd.) Gray Intermediate Shield Fern 2.9 2.2 1.4 0.5 0.5 0.5 Equisetum sylvaticum L.* Woodland Horsetail 0.7 Eupatorium fistulosum Barratt Joe-pye Weed 0.3 Euphorbia purpurea (Raf.) Fern. Glade Spurge 0.4 1.6 1.0 1.6 Euthamia graminifolia (L.) Nutt. var. graminiifolia Grass-leaved Goldenrod 1.7 17.4 1.5 1.4 Fragaria virginiana Duchesne ssp. virginiana Virginia Strawberry 0.9 0.2 Galium asprellum Michx. Rough Bedstraw 0.5 1.8 4.0 1.9 4.0 Galium tinctorium (L.) Scop. Clayton’s Bedstraw 2.4 4.8 1.1 1.0 Galium triflorum Michx. Sweet-scented Bedstraw 0.9 Geranium maculatum L. Wild Geranium 0.9 Geum rivale L.* Purple Avens 0.5 1.0 0.2 Glechoma hederacea L.** Ground-ivy 0.4 Glyceria canadensis (Michx.) Trin.* Rattlesnake Mannagrass 0.9 2.7 1.3 3.2 Glyceria melicaria (Michx.) F.T. Hubb. Mannagrass 1.2 3.6 3.5 0.2 Glyceria striata (Lam.) Hitchc. Fowl Mannagrass 2.9 3.0 9.2 8.8 9.5 5.6 Holcus lanatus L.** Velvet Grass 1.0 Hypericum mutilum L. Small-flowered St. Johnswort 0.6 Impatiens capensis Meerb. Jewelweed 6.9 4.8 5.9 5.9 8.7 5.6 Juncus effusus L. Common Rush 1.1 2.9 0.5 Leersia oryzoides (L.) Sweet Rice Cutgrass 11.2 1.4 2.7 4.7 1.4 Listera smallii Weig. Kidney-leaf Twayblade 0.2 Lycopus uniflorus Michx. Northern Bugleweed 1.0 2.2 0.8 0.5 0.9 Lysimachia ciliata L. Fringed Loosestrife 3.2 4.0 4.8 5.5 Maianthimum canadense Desf..* Canada Mayflower 0.4 0.3 0.5 0.5 Mentha spicata L.** Spearmint 3.5 0.5 Mimulus ringens L. Common Monkey-flower 0.5 Onoclea sensibilis L. Sensitive Fern 4.6 2.4 1.0 8.8 Osmunda cinnamomea L. Cinnamon Fern 4.1 3.4 0.9 Osmunda regalis L. var. spectabilis (Willd.) Gray Royal Fern 1.8 0.5 Oxalis montana Raf. White Wood Sorrel 0.6 1.9 1.8 0.5 1.4 Southeastern Naturalist J.S. Rentch, R.H. Fortney, J.T. Anderson, and W.N. Grafton 2015 Vol. 14, Special Issue 7 144 Table 1, continued. Species Common name T1 T2 T3 T4 T5 T6 Oxalis stricta L. Yellow Wood Sorrel 1.8 Oxypolis rigidior (L.) Coult. & Rose Cowbane 0.2 Packera aurea (L.) A. & D. Love Golden Ragwort 2.3 0.9 9.6 9.1 7.3 7.7 Phalaris arundinacea L. Reed Canary Grass 1.2 0.9 0.8 0.5 Phleum pratense L.** Timothy Grass 3.0 Poa trivialis L.** Rough Bluegrass 0.6 0.5 0.3 0.5 Polemonium van-bruntiae Britt.* Jacob’s Ladder 0.9 4.8 1.0 1.8 Polygonum hydropiperoides Michx. Mild Water-pepper 1.0 0.2 Polygonum sagittatum L. Arrow-leaved Tearthumb 1.8 2.0 1.8 1.3 4.4 0.7 Potentilla simplex Michx. Common Cinquefoil 0.5 Ranunculus acris L. var. acris** Meadow Buttercup 0.5 Ranunculus hispidus Michx. var. hispidus Hispid Buttercup 0.3 0.2 Ranunculus repens L.** Creeping Buttercup 0.9 Rubus hispidus L. Hispid Dewberry 2.2 Rubus pubescens Raf. var. pubescens Dwarf Red Raspberry 1.5 Rumex crispus L.ssp. crispus** Curly Dock 0.5 Schoenoplectus tabernaemontani (K.C. Gmel.) Palla Great Bulrush 9.6 0.5 Scirpus polyphyllus Vahl Bulrush 0.9 Scutellaria lateriflora L. var. lateriflora Mad-dog Skullcap 0.9 Solidago rugosa P. Mill. ssp. rugosa var. rugosa Wrinkle-leaf Goldenrod 0.6 1.9 1.3 1.0 1.6 Sparganium americanaum Nutt. American Bur-reed 0.9 Sphenopholis intermedia (Rydb.) Rydb. Slender Wedgegrass 0.5 Sphenopholis nitida (Biehler) Scribn. Shining Wedgegrass 1.2 0.5 Symphotrichum prenanthoides (Muhl. ex. Willd.) Nesom Crooked-stem Aster 0.3 0.5 0.2 Symphotrichum puniceum (L.) Nesom var. puniceum Purple-stem Aster 0.9 1.1 2.4 0.5 Taraxacum officinale Weber ex Wigger ssp. officinale** Common Dandelion 0.2 Thalictrum pubescens Pursh Tall Meadow-rue 3.1 1.9 0.2 Tiarella cordifolia L.* Foamflower 0.6 1.8 1.0 1.4 Triadenum virginicum (L.) Raf. Marsh St. Johnswort 1.8 Typha latifolia L. Broad-leaved Cattail 0.4 1.6 0.5 Veratrum viride Ait. False Hellebore 2.7 2.4 1.9 Viola cucullata Ait. Marsh Blue Violet 0.6 2.2 3.0 3.9 4.7 Southeastern Naturalist J.S. Rentch, R.H. Fortney, J.T. Anderson, and W.N. Grafton 2015 Vol. 14, Special Issue 7 145 Table 2. List of additional species observed in walk-arounds on belt transects, but not observed in the subplots for 6 transects in Abes Run wetland, Canaan Valley State Park, WV, 2002. * = species at or near the southernmost limit of their range, ** = exotic species. Species Common name Agrostis perennans (Walt.) Tuckerman Autumn Bent Grass Aralia nudicaulis L. Wild Sarsaparila Bidens vulgata Greene Common Beggartick Carex projecta Mack.* Necklace Sedge Carex scabrata Schwein. Rough Sedge Carex tribuloides Wahl. Blunt Broom Sedge Cerastium fontanum Baumg. ssp. vulgare (Hartman) Greuter Common Mouse-ear & Burdet Chickweed Cinna latifolia (Trev.) Griseb. Drooping Wood Reedgrass Cinna arundinacea L.* Wood Reedgrass Circaea lutetiana L. spp. canadensis (L.) Aschers. & Magnus Intermediate Enchanter’snightshade Cirsium pumilum (Nutt.) Spreng. Bull Thistle Cirsium vulgare (Savi) Ten.** Common Thistle Cornus amomum Mill. Silky Dogwood Dactylis glomerata L. ssp. glomerata** Orchard Grass Dalibardia repens L.* Star-violet Danthonia compressa Aust. Mountain Oatgrass Dichanthelium clandestinium (L.) Gould Deer-tongue Grass Dipsacus fullonum L.** Common Teasel Eleocharis tenuis (Willd.) J.A. Schultes var. tenuis Kill Cow Elaeagnus umbellata Thunb. var parviflora (Royale) Schneid.** Autumn-olive Epilobium coloratum Biehler Purple-leaved Willow-herb Epilobium ciliatum Raf. ssp. ciliatum American Willow-herb Epilobium leptophyllum Raf.* Linear-leaved Willow-herb Eriophorum virginicum L.* Cotton-grass Gratiola neglecta Torr. Clammy Hedge-hyssop Hypericum densiflorum Pursh Glade St. Johnswort Hypericum ellipticum Hook. Elliptic-leaf St. Johnswort Hypericum punctatum Lam. Dotted St. Johnswort Lotus corniculatus L.** Birds-foot Trefoil Ludwigia palustris (L.) Ell. Marsh Purslane Oenothera perennis L. Sundrops Phegopteris connectilis (Michx.) Watt Long Beech Fern Platanthera grandiflora (Bigelow) Lindl. Large Purple Fringed Orchid Polygonum hydropiper L. Common Smartweed Polygonum pensylvanicum L. Pennsylvania Smartweed Polystichum acrostichoides (Michx.) Schott. Christmas Fern Portulaca oleracea L.** Common Purslane Potentilla norvegica L. ssp. monspeliensis (L.) Aschers.& Graebn.** Norwegian Cinquefoil Ribes rotundifolium Michx. Smooth Gooseberry Rumex obtusifolius L.** Bitter Dock Saxifraga pensylvanica L.* Swamp Saxifrage Scirpus atrocinctus Fern.* Woolgrass Smilax taminoides L. Hispid Greenbrier Stellaria graminea L. Lesser Stichwort Thalictrum pubescens Pursh Tall Meadow-rue Thelypteris noveborancensis (L.) Nieuwl. New York Fern Thelypteris palustris Schott var. pubescens (Lawson) Fern. Marsh Fern Tragopogon pratensis L.ssp. pratensis** Yellow Goat’s Beard Trifolium aureum Pollich** Yellow Hop Clover Trifolium repens L.** White Clover Tusalago farfara L.** Coltsfoot Viburnum nudum L. var. nudum Wild-raisin Southeastern Naturalist J.S. Rentch, R.H. Fortney, J.T. Anderson, and W.N. Grafton 2015 Vol. 14, Special Issue 7 146 Table 3. Shrub, woody vinees, and tall seedling (10 cm < height < 1 m) density (stems/ha) for 6 transects in Abes Run wetland, Canaan Valley State Park, WV, 2002. 1 cm = 0.4 in. 1 ha = 2.49 ac. Species Common name T1 T2 T3 T4 T5 T6 Abies balsamea (L.) P. Mill Balsam Fir 40 Acer rubrum L. Red Maple 67 571 333 840 1480 Alnus incana (L.) Moench ssp. rugosa (Du Roi) Clausen Speckled Alder 57 667 5000 4480 1480 Amelanchier laevis Weigand Smooth Serviceberry 133 Betula alleghaniensis Britt. Yellow Birch 171 200 40 80 Crataegus punctata Jacq. Dotted Hawthorn 40 120 Fraxinus nigra Marsh. Black Ash 40 160 Hamamelis virginiana L. Witch-hazel 160 Ilex verticillata (L.) Gray Winterberry 67 10,333 9760 5120 2440 Picea rubens Sarg. Red Spruce 133 57 160 560 Prunus serotina Ehrh. Black Cherry 57 Quercus rubra L. Northern Red Oak 40 Rhamnus alnifolia L’Hér. Alder-leaved Buckthorn 28,733 39,920 960 21,960 Rhododendron maximum L. Great Laurel 133 67 200 520 Rosa multiflora Thunb. ex Murr. Multiflora Rose 560 80 Rosa palustris Marsh. Swamp Rose 133 280 320 Rubus allegheniensis Porter var. allegheniensis Allegheny Blackberry 457 Salix discolor Muhl. Pussy Willow 960 Sambucus nigra L. ssp. canadensis (L.) Bolli Black Elderberry 280 Smilax rotundifolia L. Common Greenbrier 67 Spiraea alba Du Roi Meadowsweet 520 Tsuga canadensis (L.) Carr. Eastern Hemlock 267 160 Viburnum dentatum L. var. dentatum Rough Arrowwood 200 4600 1440 Viburnum lentago L. Nannyberry 480 5040 Totals 800 1371 40,733 61,480 12,880 35,960 Southeastern Naturalist J.S. Rentch, R.H. Fortney, J.T. Anderson, and W.N. Grafton 2015 Vol. 14, Special Issue 7 147 Table 4. Importance values (IV, max = 100) for large tree (LT, >10 cm dbh) and small tree (ST, 2.5 cm < dbh < 10 cm) strata on 6 transects in Abes Run wetland, Canaan Valley State Park, WV, 2002. 1 cm = 0.4 in. T1 T2 T3 T4 T5 T6 Species Common name ST LT ST LT ST LT ST LT ST LT ST LT Abies balsamea Balsam Fir 10 7 6 9 36 20 22 20 Acer rubrum Red Maple 4 3 5 4 8 6 5 4 Acer pensylvanicum L. Striped Maple 1 Acer spicatum Lam. Mountain Maple 3 Amelanchier laevis Smooth Serviceberry 2 16 Betula alleghaniensis Yellow Birch 14 62 43 57 37 19 29 34 9 18 15 Crataegus punctata Dotted Hawthorn 2 Fraxinus nigra. Black Ash 16 23 44 33 14 53 13 Picea rubens Red Spruce 67 2 100 3 15 3 9 14 Prunus serotina Black Cherry 2 1 0 Sorbus americana Marsh. Mountain-ash 2 Salix discolor Pussy Willow 2 Tsuga canadensis Eastern Hemlock 19 31 57 12 30 11 22 9 12 23 32 Southeastern Naturalist J.S. Rentch, R.H. Fortney, J.T. Anderson, and W.N. Grafton 2015 Vol. 14, Special Issue 7 148 silty loam-silty clay loam layer that had been deposited upstream of the beaver dam was 8 inches (20 cm) (Fig. 2). Red parent material, classified as Mauch Chunk, underlay the A and B horizons (Fig. 2). Average depth to groundwater during the 2002 growing season was 5.5 in (14 cm). Soils were saturated for approximately 86% of the growing season. In contrast to upstream transects, we observed no standing water along this transect during this time period (Fig. 3). Transect 1 had the lowest bryophyte coverage (8.6%) and the most bare ground (25.7%) of the 6 transects. We recorded 43 plant species in the sample subplots, and an additional 45 species outside the plots. In total, 29 species were grasses or sedges. Shrub richness and total density were the lowest we recorded for the six transects. Ilex verticillata (Winterberry) and Rhododendron maximum (Great Laurel) were the only true shrubs present; of the large tree seedlings, only Tsuga canadensis (Eastern Hemlock) was present in appreciable numbers. Mean C and FQI values were 5.1 and 31.7, respectively, the lowest of the six transects. Table 5. Bryophyte species recorded on 6 transects at Abes Run wetland, Canaan Valley State Park, WV, 2001. Species Common name Mosses Aulacomnium palustre (Hedw.) Schwaegr. Swamp Ribbed Moss Brotherella recurvans (Michx.) Felish. Shiny Fern Moss Callicladium haldanianum (Grev.) Crum Pretty Branch Moss Climacium americanum Brid. American Tree Moss Dicranodontium denudatum (Brid.) Britt. in Williams Naked Windblown Moss Dicranum fuscescens Turner Dusky Fork Moss Dicranum montanum Hedw. Mountain Fork Moss Dicranum scoparium Hedw. Broom Fork Moss Hypnum imponens Hedw. Flat Fern Moss Hypnum linbergii Mitt. Seepy Fern Moss Leucobryum albidum (Brid. ex. P. Beauv.) Lindb. Small White Cushion Moss Leucobryum glaucum Hedw. Common White Cushion Moss Loeskeobryum (Hylocomium) brevirostre (Brid.) Fleish. in Broth. Pinched Mountain Moss Plagiomnium cuspidatum (Hedw.) T.J. Kop. Common Woodsy Mnium Polytrichum commune Hedw. Common Hair Cap Moss Polytrichum juniperinum Hedw. Juniper Hair Cap Moss Polytrichum pallidisetum Funck Mountain Hair Cap Moss Pylaisiadelpha tenuirostris (Bruch & Schimp. ex. Sull) W.R. Buck Slender Fern Moss Rhytidiadelphys triquestros (Hedw.) Warnst. Common Shaggy Moss Sphagnum fallax (H. Klinggr.) H. Klinggr. Sharp Longleaf Peatmoss Sphagnum palustre L. Common Spoon Peatmoss Tetraphis pellucida Hedw. Four Tooth Moss Thuidium delicatulum (Hedw.) Schimp. in B.S.G. Delicate Fern Moss Liverworts Bazzania trilobata (L.) Gray Common Bazzania Cephalozia lunulifolia (Dumort.) Dumort. Slim Crescent Liverwort Lophocolea heterophylla (Schrad.) Dumort. Variable Mailpouch Liverwort Nowellia curvifolia (Dicks.) Mitt. Wood-rust Liverwort Southeastern Naturalist J.S. Rentch, R.H. Fortney, J.T. Anderson, and W.N. Grafton 2015 Vol. 14, Special Issue 7 149 Tree stumps were scattered throughout the transect, but live trees were mostly limited to the edge of the study area. Betula alleghaniensis (Yellow Birch) and Eastern Hemlock were the most common large-tree species. Red Spruce, the most abundant species in the small tree and sapling strata, first became established in the Figure 2. Soil-horizon depth for center-sampling location of 6 transects, Abes Run wetland, Canaan Valley State Park. Figure 3. Average growing-season depth (cm) to water table for the center well of 6 transects (T1–T6) at Abes Run wetland, Canaan Valley State Park. A negative value indicates water table is below the surface. Southeastern Naturalist J.S. Rentch, R.H. Fortney, J.T. Anderson, and W.N. Grafton 2015 Vol. 14, Special Issue 7 150 1980s. The most abundant herbs were Carex atlantica (Prickly Bog Sedge), Leersia oryzoides (Rice Cutgrass), and Scheonoplectus tabernaemontani (Great Bulrush). Transect 2 Vegetation within transect 2 had a Cowardin classification of PEM1 and was similar in structure to transect 1, although forbs such as Euthamia graminifolia (Grass-leaved Goldenrod) and ferns, including Dennstaedtia punctilobula (Hayscented Fern), Intermediate Fern, and Osmunda cinnamomea (Cinnamon Fern), were more abundant than grasses and sedges. Mean C and FQI of 5.1 and 33.5, respectively, were also comparable to the values for transect 1. Approximately 7.9 in (20 cm) of soil organic matter had accumulated along the forested edges of this transect, but there was none in the center (Fig. 2). A gleyed layer of silty clay loam occurred at a depth of ~9 in (22 cm; Fig. 2) . During the 2002 growing season, the water table remained an average of 8 in (20 cm) below the surface; soils were saturated for roughly half that time period (Fig 3). As with Transect 1, this area was inundated by Castor canadensis Kuhl. (North American Beaver) in the 1970s and Red Spruce stumps were still present. Live Red Spruces were concentrated along this transect’s upland margins. Ringwidth analyses showed these stems to average 20 y old. The shrub stratum was relatively depauperate, but Rubus allegheniensis (Allegheny Blackberry) and Acer rubrum (Red Maple) seedlings were present. Transect 3 The vegetation of transect 3, which was upstream of the 1970s-era beaver pond, had a Cowardin classification of palustrine forested mixed (PFO8). This transect, as well as transects 4, 5, and 6, were compositionally and structurally more diverse than transects 1 and 2. The main differences can be attributed to: (1) a well-developed shrub stratum; (2) broken, low-density cover in the tree and small-tree strata; (3) a 39-in (100-cm)-thick organic layer (Fig. 2); and (4) a high degree of hydrologic variation along a gradient of soil type and depth from the upland boundaries to the transect center. Structural diversity was reflected in the wetland-quality assessment. Mean C and FQI values were 5.8 and 43.3, respectively. Standing water was present for 43% of the growing season, and average depth to groundwater was only 2.4 in (6 cm) (Fig. 3). Surface-water movement took the form of overland sheet flow with few defined stream chan nels. In the herbaceous stratum, only the following 3 species exceeded an average cover-value of 10%: Caltha palustris (Marsh Marigold), Golden Ragwort, and Fowl Mannagrass. We also observed 3 rare and calcium-tolerant species on this transect—Jacob’s ladder, Glade Spurge, and Black Ash. Shrub density was approximately 16,500 stems/ac (41,000 stems/ha), of which Alder-leaved Buckthorn (11,540/ac [28,733/ha]) and Winterberry (10,333/ha [4,150/ac]) were the primary components. The high stem-density of the latter species may have been partially due to sprouting associated with intensive browsing by Odocoileus virginianus Zimmerman (White-tailed Deer). The large- and small-tree strata also showed relatively high stem densities of 150 and 112 trees/ac (396 and Southeastern Naturalist J.S. Rentch, R.H. Fortney, J.T. Anderson, and W.N. Grafton 2015 Vol. 14, Special Issue 7 151 279 trees/ha), respectively, yet most individuals were small in both diameter and crown size. Thus, these strata provided only partial shade to the understory. Despite high tree densities, basal area totaled only 52.6 ft2/ac (12.1 m2/ha). Although the large- and small-tree strata were dominated by deciduous species, such as Yellow Birch and Black Ash, coniferous species such as Eastern Hemlock, Balsam Fir, and Red Spruce were also present. Establishment dates varied by species. We determined that one Eastern Hemlock tree became established in 1849, before the start of turn-of-the-century logging on the site. Balsam Fir became established in the 1940s and 1950s. The Speckled Alders on this transect were the oldest detected in the Abes Run study area, having become established in 1968. Transect 4 Also classified as PFO8, the vegetation within transect 4 was compositionally and structurally similar to what we documented in transect 3. Mean C and FQI values were 5.7 and 45.2, respectively. Groundwater remained within 1.6 in (4 cm) of the wetland surface through early July; soils were saturated for the entire growing season. Total bryophyte cover, primarily Sphagnum spp., averaged 22%, the highest recorded on the 6 transects. Depth of organic soil at the center of this transect was 37 in (95 cm). The overstory was characterized by a broken large-tree canopy above a very dense shrub-layer composed primarily of Speckled Alder, Winterberry, Alder-leaved Buckthorn, and Viburnum dentatum (Rough Arrowwood). Although total shrub density (24,500 stems/ac [61,400 stems/ha]) was the highest of the 6 transects, heavy browse of Winterberry resulted in a broken shrub canopy and alternating patches of shade and sunlight on the wetland floor. Thus, both shade-tolerant Glyceria melicaria (Mannagrass) and shade-intolerant Fowl Mannagrass and Glyceria canadensis (Rattlesnake Mannagrass) occurred here. As a result of this habitat variation, diversity in the herbaceous stratum was high. Species diversity and evenness indices were 3.33 and 0.88, respectively, and total herb-cover was 96%. We recorded a total of 86 herbaceous species on this transect; the herbaceous stratum was dominated by Marsh Marigold, Fowl Mannagrass, and Golden Ragwort. The overstory in transect 4 resembled that of transect 3, with Black Ash, Yellow Birch, and Eastern Hemlock as the dominant tree species, and Balsam Fir and Red Maple as lesser components. Red Spruce was important in the small-tree and sapling stratum (112 saplings/ac [280 saplings/ha]). The trees we sampled on transect 4 were the oldest we documented in the wetland, with 3 trees predating the turn-of-the-century logging. Two Black Ash trees became established in 1811 and 1893, respectively, and the earliest ring for one Eastern Hemlock (dbh = 7.1 in [17.8 cm]) was inferred as dating from 1759. Other Balsam Fir and Red Spruce individuals were recruited in the 1930s and 1950s, respectively. The oldest Speckled Alders dated to the 1970s and 1980s. Transect 5 The vegetation of transect 5 was also classified as PFO8. Soils were saturated during the entire growing season, with an overall mean depth of the water table of Southeastern Naturalist J.S. Rentch, R.H. Fortney, J.T. Anderson, and W.N. Grafton 2015 Vol. 14, Special Issue 7 152 4 in (10.2 cm), though it fell to 9.8 in (25 cm) in early August. Shrub density (4819 stems/ac [12,000 stems/ha]) was lower than on transects 3 and 4, principally due to higher tree-density and lower density of Alder-leaved Buckthorn. The lower density may be associated with the absence of an organic horizon in the transect’s center. As a result of lower shrub density, the understory was highly illuminated. Thus, shade-tolerant Mannagrass was an important component of transects 3 and 4, but it was replaced on transect 5 by shade-intolerant Rice Cutgrass. Similar to conditions on transect 4, the overstory on transect 5 was broken and low-density with Balsam Fir, Black Ash, and Eastern Hemlock as the dominant species. Both Black Ash and Balsam Fir became established during 1940–1970. However, Red Spruce was present only as sapling- and tall seedling-sized individuals. Impatiens capensis (Jewelweed), Carex bromoides (Brome-like Sedge), Carex gynandra (Nodding Sedge), and Fowl Mannagrass were the most abundant herbaceous species. Transect 6 Transect 6 supported two types of vegetation—PFO4 (palustrine forested evergreen) and PFO8—and closely resembled transects 3 and 4. However, this was the most diverse transect sampled (H' = 3.35). The organic horizon was ~30 in (77 cm) deep in the middle of this transect; depth to groundwater averaged 4 in (10 cm) during the growing season. Eight and 10 species occurred in the large and small-tree strata, respectively, although total large and small-tree density and basal-area values were not appreciably different from those of transects 3, 4, and 5. We recorded 12 shrub species on transect 6; 4 of these—Salix discolor (Pussy Willow), Spiraea alba (Meadowsweet), Sambucus nigra ssp. canadensis (Black Elderberry), and Viburnum lentago (Nannyberry)—occurred only on this transect. We found 61 herbaceous species in the subplots, and noted an additional 35 species in the walk-around. Onoclea sensibilis (Sensitive Fern), Marsh Marigold, Golden Ragwort, and Lysimachia ciliata (Fringed Loosestrife) were the most abundant herbs. Geum rivale (Purple Avens), Jacob’s Ladder, Swamp Saxifrage, Listera smallii (Kidney-leaf Twayblade), Alder-leaved Buckthorn, and Black Ash occurred here, all of which had C-values of 9. Thus, this transect’s FQI value was 48.2, highest of all transects. The species diversity index was 3.56, also highest of the 6 transects, and the maximum herbaceous cover-value for any single species was 8.8%, the lowest of the transects. The oldest trees were a Red Spruce and an Eastern Hemlock, established in 1830 and 1909, respectively; however, most trees established during 1930–1960. Changes in vegetation cover type, 1945–1997. A rank-comparison of 1945 and 1997 vegetative-cover classes revealed no significant differences (Kruskall-Wallis test, χ2 = 1.06, P = 0.180; Table 6). Prior to the logging era of the early 1900s, spruce–Eastern Hemlock was the predominant vegetative cover on the Valley’s floor, with Red Spruce and northern hardwood forests more important on the side slopes (Fortney 1975). Southeastern Naturalist J.S. Rentch, R.H. Fortney, J.T. Anderson, and W.N. Grafton 2015 Vol. 14, Special Issue 7 153 However, by 1945, Red Spruce was limited to mountain ridgetops and swamp forests such as those along Abes Run (Fortney and Rentch 2003). In the Abes Run watershed, upland mixed (UFO8) and deciduous (UFO1) forests showed an increase between 1945 and 1997, however, the coniferous component of the mixed-deciduous forest consisted of more Eastern Hemlock than Red Spruce in 1997. Upland coniferous forests (UFO4) were not observed in the 1945 photograph, and were noted only in 1997 (0.49 ac [0.2 ha]). Over the 52-year period, there was also a 30% (83 ac [33.4 ha]) decline in upland herbaceous cover (UHU), and a comparable increase of both upland scrub-shrub (USS1) and upland forested-cover types in the watershed. These results conform to the overall successional trends in Canaan Valley noted by Fortney and Rentch (2003). These findings reflect the secondary succession of abandoned fields to shrub thickets, principally Hypericum densiflorum (St. Johnswort) in more poorly drained areas, and Vaccinium angustifolium (Lowbush Blueberry) and Crataegus punctata (Dotted Hawthorn) in better-drained areas. In the Abes Run watershed, coniferous swamp forests (PFO4) declined by more than 50% (17.7 ac [7.1 ha]) between 1945 and 1997 (Table 6). During this period, there were also increases in wet-graminoid (PEM1), scrub-shrub (PSS1), and wet mixed forest (PFO8) cover types. The wet-graminoid increase was concentrated in old beaver-impacted areas in the lower end of the study area (transects 1 and 2), and the scrub-shrub increase occurred primarily in the uppermost reaches of the wetland (transects 5 and 6), where relatively young colonies of Pussy Willow and Speckled Alder became established in late 1980s. Discussion Although extirpated in the 1850s, the North American Beaver was re-introduced into the Valley around 1936 (Swank 1949) and had noticeable impacts on the area’s hydrology and vegetation. Beaver ponds create high-quality wetland Table 6. Changes in vegetative cover-class for Abes Run watershed, 1945–1997. PEM1, PFO4, PFO8, and PSS1 are all palustrine habitats; PEM1 vegetation is emergent and persistent; PSS1 vegetation is deciduous. 1945 1997 Code Vegetative Cover Class Area (ac) % Area (ac) % PEM1 Wet-herbaceous 3.2 0.9 15.4 4.2 PFO4 Wet-coniferous forest 32.6 8.9 14.9 4.1 PFO8 Wet-mixed forest 26.9 7.3 37.9 10.2 PSS1 Wet-scrub-shrub - - 14.4 3.9 UHU Upland-herbaceous 230.6 62.6 14.4 39.9 UFO1 Upland-deciduous forest 57.5 15.6 75.7 20.5 UFO4 Upland-coniferous forest - - 0.5 0.1 UFO8 Upland-mixed forest 17.4 4.8 27.9 7.5 USS1 Upland-deciduous shrub - - 30.4 8.2 UUV Unvegetated - - 4.5 1.2 Totals (wetland) 62.8 17.0 82.7 22.0 Totals (watershed) 368.3 100.0 369.1 100.0 Southeastern Naturalist J.S. Rentch, R.H. Fortney, J.T. Anderson, and W.N. Grafton 2015 Vol. 14, Special Issue 7 154 habitats that differ in species composition and structure from areas immediately outside the impoundments. For example, Bonner et al. (2009) found that although the oldest ponds supported twice as many rare plant species as younger ones, younger ponds were more species diverse than older ones. In Abes Run, changes in vegetative-cover class from 1945 to 1997 were associated with (1) cutting and damming activities by Beaver, particularly in the coniferous swamp forests in the lower end of the study area, and (2) gradual conversion of inundated areas to wet graminoid meadows as dams were abandoned or breached and their ponds dried. With persistent inundation, tree mortality may be rapid. Swank (1949) reported that the length of time required to water-kill trees is 1–2 years for Eastern Hemlock, Red Spruce, and Yellow Birch, and 1–3 years for Balsam Fir. Two additional stressors have contributed to the decline of swamp forests, particularly those with a Balsam Fir component. Adelges piceae Ratzeburg (Balsam Woolly Adelgid) is an invasive species introduced from Europe around 1900 (Ragenovich and Mitchell 2006). It constitutes a serious threat to both Abies fraseri (Pursh) Poir. (Fraser Fir) and Balsam Fir in the eastern US. The insect attacks trees of all sizes, although seed-bearing and mature overstory trees appear to be most susceptible (Ragenovich and Mitchell 2006). Although we did not document the degree of infestation, we observed that many firs showed evidence of being attacked or killed by Balsam Woolly Adelgid. The second stressor is the Valley’s White-tailed Deer population, which has been among the highest in the state from the 1950s to the present (Michael 1992), with ostensible impacts such as sharp browse-lines. Michael (1992) noted that prior to 1950, White-tailed Deer apparently had little impact on Balsam Fir regeneration. However, as hunting became restricted or prohibited on large tracts of private and public land, the deer population increased substantially, reaching 111–148 deer/mi2 (287–384 deer/km2) in 2005 (Cherefko et al. 2014). In view of observed high browse-pressure, Michael (1992) predicted that Balsam Fir would eventually be replaced by Red Spruce in the Valley. White-tailed Deer herbivory constitutes an intermediate-level disturbance that can both increase and decrease species diversity (see Russell et al. 2001). For example, the low levels of Balsam Fir seedlings (e.g., 16 seedlings/acre [40 seedlings/ha] observed on transect 6 may be attributable to heavy White-tailed Deer pressure because Balsam Fir is a desirable browse species. White-tailed Deer also browse rare species (Gregg 2004) such as Showy Lady’s Slipper and Highbush Cranberry. Populations of both have been severely reduced (Gregg 2004). Conversely, heavy browse of Winterberry, which was common in transects 3–6, appears to have maintained or even increased species diversity by reducing height and crown size and allowing more light to penetrate to the forest floor where several herbaceous species have now established. The distinctiveness of the Valley’s wetland habitats has been well documented (e.g., Allard and Leonard 1952; Fortney 1975, 1993; and numerous papers in this Special Issue). Among the principal features noted are a complex juxtaposition of upland and wetland habitats, the presence of plant communities at different Southeastern Naturalist J.S. Rentch, R.H. Fortney, J.T. Anderson, and W.N. Grafton 2015 Vol. 14, Special Issue 7 155 successional stages, the presence of a distinctly boreal flora, the mountain-valley frost-pocket effect on microclimate, and the impacts of anthropogenic activities on habitats and biota, including logging, fires, and farming (Fortney and Rentch 2003). All of these Valley-wide features are evident along Abes Run, and contribute to a remarkably rich flora that exhibits a high degree of naturalness in species composition and structure, as measured by mean C and FQI. Additional features that may contribute to the high species and community diversity along Abes Run include: (1) a species-rich yet non-continuous tree and shrub structure that results in a variable light regime on the wetland floor, which provides habitat to both shade-tolerant and shade-intolerant species; (2) a variable hydrologic regime where the depth to the water table varies considerably both temporally and over short distances from the wetland edge to the center; (3) the influence of a limestone substrate (Chambers et al. 2015 [this issue], Fortney et al. 2015 [this issue], Matchen 2015 [this issue], Sencindiver et al. 2015 [this issue]) that provides sufficient nutrients for both acidophilic and calciophilic plants; and (4) the apparent absence of destructive slash fires that affected the rest of the Valley (Adams and Kochenderfer 2015 [this issue], Carvell 2015 [this issue]), as evidenced by the presence of cohorts of trees that predate turnof- the-century logging. Our comparison of 1945 and 1997 aerial photography yielded an estimate of the vegetation changes that occurred in Abes Run over those 52 years. In the uplands, successional patterns generally followed conventional autoecological models (e.g., Smith 1996) in which herbaceous-dominated communities are replaced by shrubs that are, in turn, replaced by forests. In the Abes Run wetland, vegetative changes were less linear or predictable. Environmental factors such as hydrology (the extent and duration of saturation and/or flooding) and disturbances (logging, Beaver, White-tailed Deer, pathogens) have, at times, overshadowed biotic factors, and diverted the expected successional course. Conclusions This study provides baseline data for a small, botanically unique wetland complex that supports many rare plant species and several rare wetland plant communities. Small, isolated, and patchy headwater wetlands such as Abes Run are a significant resource because they serve as refugia for a host of wetland- obligate plants (Byers et al. 2007). Results from our aerial photographic assessment of vegetation changes over 52 years suggest that this wetland has shown a high degree of resiliency despite several episodes of natural and anthropogenic disturbance. At present, principal stress-factors include plant pests, herbivory by White-tailed Deer, and alteration of the hydrology by North American Beaver. Some stressors, like Mprth American Beaver, White-tailed Deer, and changes in land-use and land-cover may be relatively manageable at the local level, while others, such as climate change, acid deposition, and introductions of exotic pests and pathogens are less amenable to local control. Efforts by park managers to minimize disturbances to the hydrology of Abes Run are critical for maintaining the integrity of this special resource. Southeastern Naturalist J.S. Rentch, R.H. Fortney, J.T. Anderson, and W.N. Grafton 2015 Vol. 14, Special Issue 7 156 Acknowledgments The authors thank James Gorman, Sam Lamont, and Susan Studlar for soils, hydrologic, and bryophyte data, respectively, and the Division of Forestry and Natural Resources at West Virginia University. We also thank John Northeimer of Canaan Valley State Park for providing water-table data. Partial funding was provided by a McIntire-Stennis grant and by a grant from the Canaan Valley Institute and the US Department of Agriculture. Literature Cited Adams, M.B., and J.N. Kochenderfer. 2015. The Fernow Experimental Forest and the Canaan Valley: A history of research. Southeastern Naturalist 14(Special Issue 7):433–440. Allard, H.A., and E.C. Leonard. 1952. The Canaan and Stony River valleys of West Virginia, their former magnificent spruce forests, their vegetation, and floristics today. Castanea 17:1–60. Bonner, J.L., J.T. Anderson, J.S. Rentch, and W.N. 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