Plants and Wildlife
This wooded stream valley of 1,800 acres within the city of Philadelphia provides a valuable natural refuge for wildlife and native plants.
There are at least 20 different species of aquatic creatures in the creek bed and a considerable variety of mammals: opossums, deer, raccoons, groundhogs, red foxes, and more. Hard to find but still present are salamanders, frogs and toads, turtles, and snakes. With the creek flowing through a thick, forested gorge, and many subsidiary streams providing wetland habitat, the valley has a great variety of wildlife.
Today, the canopy and understory of the Wissahickon are challenged by a number of factors: erosion of soil and trails; dramatic increase in the deer population; and increasing recreational use. These combined forces have decimated much of the native plants in the understory of the Wissahickon Valley, as well as young trees that could replace fallen canopy trees in the future. Invasive species, such as Japanese knotweed, multiflora rose, privet, honeysuckle, and mile-a-minute, immediately fill this ecological gap, along with aggressive native species like devil’s walking stick and poison ivy. As the ratio of native to invasive plant species becomes unbalanced, invasives claim a dominant position and alter the structure of the ecosystem. The forest understory loses many of the plant and insect species that support the Wissahickon’s biodiversity, while the land along the creek, or riparian zone, suffers from soil erosion.