A cataract bog is a rare ecological community formed where a permanent stream flows over a

granite Granite ( ) is a coarse-grained (phanerite, phaneritic) intrusive rock, intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly coo ...

outcropping. The sheeting of water keeps the edges of the rock wet without eroding the soil; in this precarious location no tree or large shrub can maintain a roothold. The result is a narrow, permanently wet, sunny habitat. While a cataract bog is host to plants typical of a bog, it is technically a

fen A fen is a type of peat-accumulating wetland fed by mineral-rich ground or surface water. It is one of the main types of wetland along with marshes, swamps, and bogs. Bogs and fens, both peat-forming ecosystems, are also known as mires ...

Bog A bog or bogland is a wetland that accumulates peat as a deposit of dead plant materials often mosses, typically sphagnum moss. It is one of the four main types of wetlands. Other names for bogs include mire, mosses, quagmire, and musk ...

s get water from the atmosphere, while fens get their water from groundwater seepage. Cataract bogs inhabit a narrow, linear zone next to the stream and are partly shaded by trees and shrubs in the adjacent plant communities. Algae growing on the rocks can make the surface slippery and dangerous for those exploring a cataract bog.

Typical species

The rushing water carves out small depressions where soil accumulates, forming micro-islands that play host to plants that thrive with low levels of nutrients and shallow root structures. Typical species include

Sphagnum moss ''Sphagnum'' is a genus of approximately 380 accepted species of mosses, commonly known as sphagnum moss, also bog moss and quacker moss (although that term is also sometimes used for peat). Accumulations of ''Sphagnum'' can store water, since ...

; carnivorous plants such as round-leaf sundew (''

Drosera rotundifolia ''Drosera rotundifolia'', the round-leaved sundew, roundleaf sundew, or common sundew, is a carnivorous species of flowering plant that grows in bogs, marshes and fens. One of the most widespread sundew species, it has a circumboreal distribut ...

''), pitcher plants (''

Sarracenia purpurea ''Sarracenia purpurea'', the purple pitcher plant, northern pitcher plant, turtle socks, or side-saddle flower, is a carnivorous plant in the family Sarraceniaceae. Taxonomy The species is further divided into two subspecies, ''S. purpurea'' subsp. ...

'' and '' S. jonesii''), and horned bladderwort ('' Utricularia cornuta''); several orchid species such as common grass pink ('' Calopogon tuberosus''), small green wood-orchid ('' Platanthera clavellata''), rose pogonia ('' Pogonia ophioglossoides''), and nodding ladies'-tresses (''

Spiranthes cernua ''Spiranthes cernua'', commonly called nodding lady's tresses, or nodding ladies' tresses, is a species of orchid occurring from Maritime Canada to the eastern and southern United States. As the common name suggests ''cernua'' means "nodding", or ...

''). Other plants found in cataract bogs are limeseep grass-of-Parnassus ('' Parnassia grandifolia''), Indian paint brush (''

Castilleja coccinea ''Castilleja coccinea'', commonly known as scarlet Indian paintbrush or scarlet painted-cup, is a biennial plant, biennial flowering plant in the Orobanchaceae (broomrape) family. It is usually found in prairies, rocky glades, moist and open wood ...

''), stiff cowbane ('' Oxypolis rigidior''), Appalachian bluet ('' Houstonia serpyllifolia'') and northern sundrops ('' Oenothera tetragona''). The plant communities are fragile because of their tenuous attachment to thin soil above the rock substrate. During prolonged drought, the stream may dry up and the edges of the micro-islands curl up. Heavy rainfall can then wash away the micro-islands, so a cataract bog is in a continual state of change and renewal.

Location

Cataract bogs are found only in the southern

Appalachian Mountains The Appalachian Mountains, often called the Appalachians, are a mountain range in eastern to northeastern North America. The term "Appalachian" refers to several different regions associated with the mountain range, and its surrounding terrain ...

of the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

, at elevations of between . They are restricted to the Blue Ridge Escarpment region of

South Carolina South Carolina ( ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders North Carolina to the north and northeast, the Atlantic Ocean to the southeast, and Georgia (U.S. state), Georg ...

and a small area of

North Carolina North Carolina ( ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It is bordered by Virginia to the north, the Atlantic Ocean to the east, South Carolina to the south, Georgia (U.S. stat ...

, a region with exceptionally high rainfall.

References

{{Wetlands Appalachian bogs Landforms Wetlands