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Conejohela Flats COLUMBIA AVE West Hempfield Township 462 Columbia Boro

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Conejohela Flats COLUMBIA AVE West Hempfield Township 462 Columbia Boro 30 Conejohela Flats COLUMBIA AVE West Hempfield Township 462 Columbia Boro Wrightsville Boro 441 FRANKLIN RD Hellam Township Lower Windsor Township Manor Township PENN ST (LimitAerialof imagery) RIVER RD Susquehanna River East Prospect Lancaster County Natural Heritage Inventory Update 2008 Legend LOWER WINDSOR Species of concern core habitat Natural Heritage Area Roads Supporting Landscape PA Turnpike Streams All other roads 425 Riparian Buffer Municipal Boundary Chanceford Township LANCASTER Miles YORK COUNTY 0 0.25 0.5 1 1.5 2 COUNTY Conejohela Flats Conejohela Flats – Exceptional significance PNHP Rank1 State Last Observed Species of Concern: Quality2 Global State Status1 (y-m-d) Plants: Scarlet ammannia (Ammannia coccinea) G5 S2 PE 2003-08-15 B Tooth-cup (Rotala ramosior) G5 S3 PR 2003-08-15 B Animals: Great Egret (Casmerodius albus) G5 S1B PE 1986 F Prothonotary Warbler (Protonotaria citrea) G5 S2S3B - 1989-06-02 B Sensitive species of concern-(A)3 - - - 1991-05-18 E Sensitive species of concern-(B)3 - - - 2003 E Sensitive species of concern-(C)3 - - - 1989-06-02 E Sensitive species of concern-(D)3 - - - 1987 E 1 Please refer to Appendix IV for an explanation of PNHP ranks and legal status 2 Please refer to Appendix V for an explanation of quality ranks 3 This species is not named at the request of the agency overseeing its protection Location: This Natural Heritage Area describes the section of the Susquehanna River and the adjacent banks between the Columbia – Wrightsville Bridge down river to Turkey Hill, south of Washington Borough. The water level of this section of the river is impacted by Safe harbor Dam, which forms this slow water area referred to as Lake Clarke, a popular area for recreational boating. o Municipalities: o Manor Township, (Lancaster County) o West Hempfield Township, (Lancaster County) o Columbia Borough, (Lancaster County) o Washington Borough, (Lancaster County) o Chanceford Township, (York County) o Hellam Township, (York County) o Lower Windsor Township, (York County) o Wrightsville Borough, (York County) o USGS Quadrangles: o Columbia East Quadrangle o Columbia West Quadrangle o Red Lion Quadrangle o Safe Harbor Quadrangle o 1990 Lancaster County Natural Areas Inventory reference: o “Rookery Islands (Conejohela Flats)” – (Columbia East Quadrangle) o “Rookery Islands (Conejohela Flats)” – (Safe Harbor Quadrangle) Description: Conejohela Flats is a combination of small brushy islands and mud flats located in the Susquehanna River just west of Washington Borough. The series of islands and the shoreline are periodically 189 Conejohela Flats disturbed by seasonal flooding and scouring by ice. The mud flats are also exposed when the water level is lowered by the Safe Harbor Dam to generate electricity. This area has been designated an Important Bird Area by the Pennsylvania Audubon Society primarily because the mud flats provide an important habitat for shore birds that is found in few other locations in Pennsylvania. A rookery, (a concentrated breeding area for birds), exists within the island habitat. Many other species of wetland birds and waterfowl also use this area during migration. During one survey, 73 species of wadding birds, ducks and shorebirds were observed. Grassy flats and gravel bars are important for feeding and resting during both spring and fall migration. The adjacent uplands and forested slopes are an important aspect of this Natural Heritage Area, as these terrestrial habitats provide essential nesting and breeding locations for several of the species of concern. Species of Concern Considerations: Plants: o Scarlet ammannia is a globally secure (G5) though state imperiled (S2) plant that inhabits various damp to wet habitats, especially on the shorelines of rivers, streams, and ponds, and may also be found in human-created disturbances that simulate natural habitats. The core habitat for this species is primarily along the damp edges of the islands, mudflats and shallow water areas. The higher elevations of the islands are not considered part of the primary habitat for this species. Conservation of this habitat type will help this species persist at this location. o Tooth cup is a globally secure (G5), state rare (S3) annual plant that occupies exposed shorelines, stream margins, streambed outcrops, and other damp, open places. The populations of toothcup that occur along streams and rivers can be enhanced by maintaining the natural seasonal fluctuations in the water level of the stream and the natural conditions of its shoreline. The core habitat for this species is primarily along the damp edges of the islands, mudflats and shallow water areas. The higher elevations of the islands are not considered part of the primary habitat for this species. Animals: o Prothonotary Warblers were documented successfully nesting for much of the 1980s. Recent records for this bird’s success at this location are lacking. The islands and the adjacent floodplain forests are the primary habitats for this species at this location. Because this bird nests in tree cavities, dead trees along the river shore and adjacent wetlands should be left standing to provide nesting habitat. Recreational boaters can have a significant negative impact on the breeding success of this species. Harassment of nesting locations can cause adults to abandon the site. A buffer from boating activities needs to be established around nesting locations during breeding season to help prevent inadvertent conflict. o Great Egret was observed successfully nesting at this location in 1986, but has not been documented recently. This area was considered a failed breeding location for this species in 1988 and 1989. Though the species has been regularly observed in the area, only breeding occurrences are considered as core habitat for bird species of concern. Regular breeding season surveys of the area should be conducted with consideration of the potential to disrupt nesting behavior. Recreational boaters can have a significant negative impact on the breeding success of this species. Harassment of nesting locations can cause adults to abandon the site. A buffer from boating activities needs to be established around nesting locations during breeding season to help prevent inadvertent conflict. o A sensitive species of concern (A) utilizes the steep, dry, southwest-facing wooded slopes along the Susquehanna River. The suitable habitat for this species is mapped as occurring from Turkey Hill all the way down to the mouth of the Conestoga River. The core habitat for this species overlaps with the Fry’s Run Slopes Natural Heritage Area. A dead specimen was found between the two rails of the train tracks along the river. The railroad can be a substantial barrier for small animal movement between upland and lowland habitats. Periodic under-track culverts, or other means of mitigating the barrier effect of the tracks, should be integrated into future railroad maintenance plans. 190 Conejohela Flats o Several populations of three additional sensitive species of concern (B, C & D) were documented along this stretch of the river. The core habitat for these sensitive species of concern is both the river and the adjacent upland forest. These sensitive species of concern require abundant food source in the river and its tributaries as well as breeding areas in the adjacent upland forest. This can be achieved by preserving and improving the water quality of the Susquehanna River and by protecting and expanding the natural vegetation buffer along the river and all its tributaries. Recreational boaters can have a significant negative impact on the breeding success of these species. Harassment of nesting locations can cause adults to abandon the site. A buffer from boating activities needs to be established around nesting locations during breeding season to help prevent inadvertent conflict. Forest Cover / Natural Communities: The plant community types depicted are only approximations delineated from 2005 aerial photography interpretation and were followed up with minimal selective ground-truthing. Community types follow “Terrestrial & Palustrine Plant Communities of Pennsylvania” (Fike 1999) where appropriate, and describe general land cover types where they are not (*). o This Natural Heritage Area is drawn tightly along the banks of the Susquehanna River, with most of the area in the river itself. The natural communities are primarily associated with the river floodplain, which is dominated by silver maple floodplain forest and river birch-sycamore floodplain scrub. Lower islands have expanses of grassy flats and sand/gravel bars. o The western shore of the river and the adjacent uplands have significant patches of forest cover including several interior forest blocks. o The Lancaster County side of the river is dominated by agriculture, urban and suburban land uses with only a few small parcels of forest cover remaining. The floodplain between the railroad tracks and the river is seasonally flooded and contains remnants of a silver maple floodplain forest. o Terrestrial (upland) communities: o Red oak-mixed hardwood forest o Hemlock-tuliptree-birch forest o Dry oak-heath forest o modified successional forest* o Palustrine (wetland) communities: o River birch-sycamore floodplain scrub o Silver maple floodplain forest Ownership: o Much of the species of concern core habitat occurs in floodplain habitat that is subject to such intense flooding that it should be considered part of the river. o Most of the islands in the river are owned by
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