Pennsylvania Wetlands: Bogs
Overview
Bog environments are typically found in kettle ponds left behind by the last ice age or in low-lying peatlands across the state. These nutrient-deficient saturated wetland oases hold many natural treasures and make you feel as if you're stepping back in time. Plant life is dwarfed and seemingly misplaced in comparison to surrounding habitats. Magical places with a carpet of moss-covered tussocks, grass-like sedges, heath shrubs, and coniferous trees that are typically found in the Northern Territories of Canada. Upon a closer look, you'll be drawn in by the beauty of various species of orchids and carnivorous plants.
Hydrology
Bogs are typically closed systems and recharge through precipitation; however, there are some that have minimal groundwater discharge and some that take on flowing surface water. If the groundwater or surface water flow is greater and contributes enough minerals to change the soil chemistry, it would be considered a fen, which will be outlined in a future article. The wetland area is comprised of saturated peat, which is partially decayed plant matter. The still water and cation exchange generated through the decomposition process makes for a very acidic and nutrient-deficient wetland environment.
Ecology
Plant communities found in bogs have adapted to live in acidic and nutrient-poor conditions.
Just above the layer of saturated peat, bogs are typically covered in carpets of moss. The primary moss family is sphagnum, a peat moss, but haircap, fern, pocket, and various other moss families can also be found, depending on conditions. Growing from the moss tussocks are various species of sedges, a notable species being bog cotton, and heath shrubs like leatherleaf, blueberry, laurels, azaleas, and cranberry.
Perched on the peat and rising above the bog to create a sparse canopy are shallow-rooted conifers, common species like black spruce, white pine, larch, and the rarer balsam fir. The larch is unique in the sense that it is a deciduous conifer, its needles fade to gold and drop for the winter, and regenerate in the spring.
The most fascinating plants found in bogs are orchids and carnivorous plants. Orchids thrive in acidic conditions; common species are lady tresses, rose pogonia, grass-pink, white-fringed, and yellow lady slippers. Carnivorous plants are not dependent on soil nutrients, as they generate their own by capturing and digesting insects. The two terrestrial carnivorous plants found in the state are the purple pitcher plant and the sundew. Pitcher plants capture and digest their prey in their tubular leaves, while sundews produce a sweet, sticky digestive nectar at the end of their leaves to consume their prey.
Many animals can be found inhabiting and passing through bogs. Passing mammals are most common and include bears, beavers, bobcats, coyotes, deer, foxes, otters, and porcupines. They utilize the seasonal cover and food resources. Many bird species pass through and are dependent on the individual bog plant diversity. Reptile and amphibian species like frogs, toads, and salamanders will pass through but have difficulty tolerating the acidic environment.
Visit
If you'd like to explore the wonder of a bog yourself, consider visiting one of the following. Note that these are sensitive areas and permission or private tours may need to be arranged.
- Western Pennsylvania: Forbes State Forest - Spruce Flats Bog & Wildlife Area Guide (PDF)
- Central Pennsylvania: Black Moshannon State Park - Black Moshannon State Park Guide (PDF)
- Eastern Pennsylvania: Tannersville Cranberry Bog - Visit Tannersville Cranberry Bog
Reference
United States, Congress, Fish and Wildlife Service, et al. The Ecology of Peat Bogs of the Glaciated Northeastern United States: A Community Profile, USFWS, 1987, pp. 1-100.
