Allegheny River from Eagle Rock to Rockmere

This meandering section of the Allegheny River flows along a primarily forested shoreline, with some agriculture and residential housing on the south bank of Walnut Bend. These meanders create some highly diverse aquatic and terrestrial habitats that house a number of species of concern. The river itself contains populations of wavy-rayed lampmussel (Lampsilis fasciola), long-solid (Fusconaia subrotunda), elktoe (Alasmidonta marginata), round pigtoe (Pleurobema sintoxia), red-head pondweed (Potamogeton richardsonii), and three other species of concern, not named at the request of the agency overseeing their protection. Additionally, blue false-indigo (Baptisia australis) was recently documented along the shoreline of the Allegheny in this stretch. All of these species rely on the water quality of the Allegheny River, and in the case of the blue false-indigo, the periodic scouring that occurs from the natural flooding regimes.

Threats & Stresses: Threats to the populations of rare species at this site include a decrease in water quality, invasive aquatic species such as the zebra and quagga mussels (Dreissena spp.), and invasive plant species along the shoreline. Japanese knotweed (Fallopia japonica) is a difficult invasive to control, and it poses a major threat to riparian plant communities by displacing them with monocultures of Japanese knotweed. The natural scouring process in the portion of the shoreline inhabited by blue false-indigo can be easily colonized by Japanese knotweed. If the periodic floods of the Upper Allegheny River are limited by dams, scouring is reduced, leading to conditions in which Japanese knotweed can thrive and displace blue false- indigo. Native freshwater mussel diversity is Charlie Eichelberger (PNHP) highest where the flow of the river varies, The flowers of blue false-indigo (Baptisia creating a diversity of shallow and deeper australis) are quite showy, and the blooms are visible from May through August. habitats, frequently with a unique mix of substrates dictated by the varied flow. Disruptions to the natural flow, including dams and dredging, decrease the quality of the habitat used by freshwater mussels.

Conservation Recommendations: The upper Allegheny River stands out because of its free flowing nature. Apart from the significant dam which impounds Tionesta Creek, the upper Allegheny River drainage is free of significant dams. This unimpeded flow is representative of how much of the Allegheny River appeared before the dams now found southward created the slackwater pools, which homogenized the aquatic and riparian habitats. Before the construction of these dams, the southern stretches of the Allegheny River appeared similar to the sections flowing through Venango County (Zimmerman & Podniesinski 2008). Not only is it one of the most picturesque waterways in Pennsylvania, the upper Allegheny River contains a wide array of aquatic and riparian habitats. Damming of the river to move the navigational slackwater portions further upstream would seriously degrade the remaining free flowing habitats found in the upper Allegheny River inhabited by both common and rare species.