Plants and Animals
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Plants
In the Subcalcareous Cliff and Rock Outcrop natural community, plants cover less than half of the exposed bedrock of the cliffs. Wild hydrangea is a common shrub on these cliffs, and you’ll often see eastern poison-ivy growing less like a vine and more like a shurb. Smaller plants include ferns such as rock polypody and marginal woodfern. Another small plant well-suited to this habitat is woodland stonecrop, a member of the sedum family. Because of the lack of soil, trees are uncommon, although there may be young or stunted green ash or red maple trees growing at the base of the cliff or even on the cliff face. Sweet birch trees sometimes overhang the cliffs from above, providing shade.
Canopy Trees
The trees whose crowns intercept most of the sunlight in a forest stand. The uppermost layer of a forest.
Understory Trees
Small trees and young specimens of large trees growing beneath the canopy trees. Also called the subcanopy.
Shrubs, Saplings, and Vines
Shrubs, juvenile trees and vines at the right height to give birds and others a perch up off the ground but below the trees.
- common ninebark
- eastern poison-ivy
- northern spicebush
- sawtooth blackberry
- wild hydrangea
Low Plants (Field Layer)
Plants growing low to the ground. This includes small shrubs and tree seedlings.
rock polypody
marginal woodfern
woodland stonecrop
Canadian blacksnakeroot (occasional)
common blue wood aster (occasional)
eastern bottlebrush grass (occasional)
pale jewelweed (occasional)
red columbine (occasional)
zigzag goldenrod (occasional)
Non-Native Invasive Plant Species
Living on a cliff is pretty challenging, so there aren’t many non-native invasive plants in this natural community besides Japanese stiltgrass* and garlic mustard*. See Ecological Threats.
Animals
Peregrine falcons were absent from Harpers Ferry NHP for many years after their populations plummeted in the mid-1900s, but a pair began nesting on the Maryland Heights cliffs in 2015. The steep cliffs of the Subcalcareous Cliff and Rock Outcrop protect the birds from many potential predators, and from disruptions to their nesting. Park staff restrict access to parts of the cliffs to try to help the pair succeed in producing offspring.
Even though natural communities aren’t named after animals, animals do play a crucial role in maintaining natural communities. Plants and animals need each other. To name just a few examples, plants provide food and habitat for animals, and animals help plants reproduce by spreading pollen and seeds. To learn more, see The Role of Animals in Natural Communities in Ecology Basics.
Check out iNaturalist to see photos of animals (and plants!) that people have seen in Harpers Ferry National Historical Park.