CHAPTER 9 Skippack Creek Conservation Landscape Evansburg State Park makes up the major portion of the Skippack Creek Conservation Land- scape. The landscape contains extensive, mostly forested, fl oodplains along the creek that serve an important ecological role in reducing fl ood damage throughout the region. Forested slopes along the creek also provide habitat for a diversity of plant and animal species including riparian specialists. Description Location The landscape extends along both sides of Skippack Creek for almost 7 miles from its confl uence with the Perkiomen Creek to just below Sumneytown Pike. It covers 10,221.3 acres and includes parts of Lower Providence, Skippack, Worcester, Towamencin, and Lower Salford Townships (Figure 9.1). The landscape includes Evansburg State Park, the largest protected parcel of open space in Montgomery County. At its southern end, the Skippack Creek Conservation Landscape connects with the Middle Schuylkill River Conservation Landscape. Hydrology The entire landscape is within the Skippack Creek watershed, a sub-basin of the Perkiomen Creek Watershed. In addition to the main stem of the Skippack Creek, the landscape also includes the lower portions of several tributaries including Zacharias Creek, Towamencin Creek, and the West Branch of the Skippack Creek. The Skippack Creek and its tributaries are classifi ed as TSF (trout stocked fi shery). The landscape contains 880.7 acres of fl oodplains along Skippack Creek and its tributaries of which 606.5 (69 percent) are forested. In addition to supporting fi ve distinct plant associations and a variety of plant and animal species, fl oodplains perform vital ecosystem functions including fl ood control, fi ltration, and ground water recharge. Geology Reddish-brown shales, siltstones, and sandstones of the Brunswick Formation underlie the northern two-thirds of the landscape. To the south, several bands of Locka- Skippack Creek in Evansburg State Park, Photo by tong Formation shales and argillites are present. A Nancy Khan Natural Areas Inventory Update 2007 151 small diabase dike along the east side of the creek just south of Stump Hall Road undoubtedly is responsible for the steep northwest-facing slope at this location (Figure 9.2). Forest Cover Forests cover 3,779.8 acres of this landscape, 37 percent of the land surface; 1,823.2 acres meet the criteria for interior forest (Figure 9.3). Critical Features Two small populations of early buttercup (Pennsylvania endangered) persist at sites in Evansburg State Park. Although one population appears to be fairly stable, the smaller one is being out- competed by invasive species. Canada yew, a watchlist species, was also present in the park at a site referred to as “Green Hill Woods” in the 1995 Natural Areas Inventory, but its future is in doubt due to severe browsing by deer. Redbelly turtle, a threatened species in Pennsylvania, was found in Skippack Creek in 2006. The 1995 Montgomery County Natural Areas Inventory also identifi ed Eagleville Woods as a locally signifi cant site dominated by beech and various oak species. Unfortunately this site, which is located on a tributary of Skippack Creek, has been subdivided and construction of new homes is imminent. Birds – Data from the 2004-2008 Breeding Bird Atlas for the Skippack Creek Conservation Landscape, as defi ned in this re- port, include a total of 54 species (Table 9.1). Several, including Belted Kingfi sher, Wood Duck, and Louisiana Waterthrush are riparian specialists. Forest interior species, another group of in- terest, are represented by Scarlet Tanager, Barred Owl, Blue-gray Baltimore Oriole, Photo by Gnatcatcher, and Wood Thrush. Howard Eskin Table 9.1 — Bird Occurrence in the Skippack Creek Conservation Landscape ( 2004-2008 data for the Skippack Creek Conservation Landscape from the Breeding Bird Atlas) Acadian Flycatcher Downy Woodpecker Northern Parula American Crow Eastern Bluebird Northern Rough-winged Swallow American Goldfi nch Eastern Kingbird Osprey American Robin Eastern Phoebe Red-bellied Woodpecker American Woodcock Eastern Towhee Red-tailed Hawk Baltimore Oriole European Starling Rose-breasted Grosbeak Barn Swallow Field Sparrow Scarlet Tanager Barred Owl Gray Catbird Tree Swallow Belted Kingfi sher Great Blue Heron Tufted Titmouse Blue-gray Gnatcatcher Great Crested Flycatcher Turkey Vulture Blue-winged Warbler Hairy Woodpecker Warbling Vireo Brown Thrasher Indigo Bunting White-breasted Nuthatch Brown-headed Cowbird Killdeer Wild Turkey Canada Goose Louisiana Waterthrush Wood Duck Carolina Wren Mallard Wood Thrush Cedar Waxwing Mourning Dove Yellow Warbler Common Yellowthroat Northern Cardinal Yellow-billed Cuckoo Cooper’s Hawk Northern Flicker Yellow-throated Vireo 152 Natural Areas Inventory Update 2007 Natural Areas Inventory Update 2007 153 154 Natural Areas Inventory Update 2007 Natural Areas Inventory Update 2007 155 156 Natural Areas Inventory Update 2007 Past Uses European immigrants arrived in the Skippack Creek landscape beginning in 1702. The land was cleared for farming with the re- sult that by 1756 one-third of the land was under cultivation. By the late 1800s, remnant forests persisted only on steep slopes and fl oodplains. Of the seven mills that once operated along the banks of Skippack Creek, only one remains today. The Skippack Creek Landscape Bird’s-eye-view of Collegeville in 1894 by T. M. Fowler. was still mainly agrarian in the Source: http://lcweb2.loc.gov/ammem/pmhtml/panhome.html 1960s when the Commonwealth of Pennsylvania purchased land with the goal of creating a 1,200-acre impoundment for water supply and recreation. Local opposition to the plan to fl ood the valley and demolish over 200 historic buildings stalled the dam project, but creation of a multiuse park proceeded. Many his- toric buildings remain in the park, some in badly deteriorated condition. Preservation Status and Other Designations Twenty-six (26) percent of the land in this landscape is already preserved, including the 3,349 acres in Evansburg State Park and township-owned parcels along the lower Skippack Creek and several of its tributaries (Figure 9.4). The Evansburg Historical District was placed on the National Register of Historic Places in 1972. Core Areas Evansburg State Park Covering 3,349 acres, Evansburg State Park accounts for most of the Skippack Creek Conservation Landscape. Furthermore, it is the largest parcel of protected open space in Montgomery County. Plant Diversity – A vegetation inventory of the park conducted by Morris Arboretum person- nel in 2004 resulted in a list of 545 species of vascular plants of which 45% were non-na- tive (Table 9.2; Appendix 9.A). This is a high percentage of non-native species and refl ects the Early buttercups such as this bloom in Evansburg State Park. presence in the park of many former farms and Photo by Tom Barnes University of Kentucky. Natural Areas Inventory Update 2007 157 homesteads. Two native plants were found that are of conservation concern, early buttercup (PA threatened) and Canada yew (watchlist). Table 9.2 — Plant Diversity at Evansburg State Park (from Khan 2005) Plant Type Native Introduced Total Species of Concern Aquatic plants 13 2 15 0 Ferns 17 0 17 0 Grasses, sedges and rushes 57 19 76 0 Wildfl owers 112 170 282 1 Trees, shrubs, and woody vines 97 58 155 1 totals 296 249 545 2 Plant Communities – Sixteen natural community types were identifi ed in Evansburg State Park (Table 9.3); seven types were sampled using the point quarter methodology to quantify canopy composition and nested plots for understory and shrub composition. Much of the park contains successional habitat, which has developed in the past 50 years on abandoned farmland; however, mature fl oodplain forest borders Skippack Creek. Steep slopes along the creek support mature red oak – mixed hardwood forests, or in one case a dry hemlock - oak association. Sugar maple was prominent in six of the 11 transects studied. Table 9.3 — Plant Communities of Evansburg State Park (from Khan 2005) Plant Community Type Total Acreage Dry oak – heath forest 5.8 Dry hemlock – oak forest 2.3 Red maple terrestrial forest 22.8 Red oak – mixed hardwood forest 281.0 Sugar maple – basswood forest 22.5 Tuliptree – beech – maple forest 40. Bottomland oak – mixed hardwood forest 146.1 Silver maple fl oodplain forest 19.4 Sycamore – box-elder fl oodplain forest 187.1 Virginia pine – mixed oak woodland 1.7 Red maple – mixed shrub palustrine woodland 2.9 Black willow scrub/shrub palustrine woodland 9.6 Calcareous opening/cliff 0.2 Herbaceous marsh/wet meadow 9.5 Skunk-cabbage forest seep 0.6 Emergent aquatics scattered Forest plantations 112.1 Successional forest and thicket 1468.1 Cultivated/managed fi elds 686.8 158 Natural Areas Inventory Update 2007 Reptiles and Amphibians – Ten species of reptiles and amphibians have been documented in Evansburg State Park as part of this study (Table 9.4). Most are common species. Only the red- belly turtle has conservation status. Table 9.4 — Reptiles and Amphibians of Evansburg State Park (Source: surveys by Marlin Corn 2006-07) Salamanders Northern redback salamander Northern two-lined salamander Spotted salamander Frogs and Toads Green frog Spring peeper American toad Turtles Eastern painted turtle Common snapping turtle Redbelly turtle Snakes Northern black racer Eastern garter snake Northern ringneck snake Northern water snake Birds – See bird data for the Skippack Creek Conservation Landscape as a whole above. Deer Status – Although much of the park is open for hunting, evidence of over browsing by deer was detected in studies of understory and herba- ceous layers throughout (Khan 2005). In general there was a paucity of tree saplings, which indicates a failure of canopy species to regenerate. Highly preferred species such as oaks and hemlock were noticeably absent from the understory. Oaks were present in the canopy in six tran- sects, and co-dominant in 3, but in only one transect was there oak in lower layers of the forest.