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

granite Granite () is a coarse-grained (phaneritic) 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 cools and solidifies undergro ...

outcropping An outcrop or rocky outcrop is a visible exposure of bedrock or ancient superficial deposits on the surface of the Earth. Features Outcrops do not cover the majority of the Earth's land surface because in most places the bedrock or superficial ...

. 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 wetlands along with marshes, swamps, and bogs. Bogs and fens, both peat-forming ecosystems, are also known as mires. T ...

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 muskeg; a ...

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, peat moss, also bog moss and quacker moss (although that term is also sometimes used for peat). Accumulations of ''Sphagnum'' can store wa ...

; 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. Description Like other species of ''Sarracenia'', ''S. purpurea'' obtains most ...

'' and '' S. jonesii''), and horned bladderwort ('' Utricularia cornuta''); several orchid species such as common grass pink (''

Calopogon tuberosus ''Calopogon tuberosus'', the tuberous grass pink, is an orchid native to eastern North America. Distribution In the United States, it occurs from as far southwest as Texas and Oklahoma and southeast to the Florida Everglades to as far northeast ...

''), small green wood-orchid (''

Platanthera clavellata ''Platanthera clavellata'', commonly known as the club-spur orchid or small green wood orchid, is a terrestrial orchid of North America. Description ''Platanthera clavellata'' plants are 4-16" tall. It is one of the smallest species out of the ...

''), rose pogonia (''

Pogonia ophioglossoides ''Pogonia ophioglossoides'', the snakemouth orchid or rose pogonia, is a species of orchid occurring from central Canada to the east-central and eastern United States. It is the type species of the genus '' Pogonia''. It is pollinated by bees. Th ...

''), 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 The genus ''Parnassia'', also known as grass of Parnassus or bog-stars, are plants now placed in the family Celastraceae, formerly classified in Parnassiaceae or Saxifragaceae. The plants occur in arctic and alpine habitats, as well as in dune ...

grandifolia''), Indian paint brush ('' Castilleja coccinea''), stiff cowbane (''

Oxypolis rigidior ''Oxypolis rigidior'', known as cowbane, common water dropwort, stiff cowbane, or pig-potato, is a species of flowering plant in the carrot family native to eastern North America. It is a perennial wildflower found in wet habitats. ''Oxypolis r ...

''), Appalachian bluet (''

Houstonia serpyllifolia ''Houstonia serpyllifolia'', commonly called thymeleaf bluet, creeping bluet, mountain bluet, Appalachian bluet or Michaux's bluets is a species of plant in the coffee family (Rubiaceae). It is native to the eastern United States, where it is fou ...

'') 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, (french: Appalaches), are a system of mountains in eastern to northeastern North America. The Appalachians first formed roughly 480 million years ago during the Ordovician Period. They ...

of the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

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

South Carolina )''Animis opibusque parati'' ( for, , Latin, Prepared in mind and resources, links=no) , anthem = " Carolina";" South Carolina On My Mind" , Former = Province of South Carolina , seat = Columbia , LargestCity = Charleston , LargestMetro = ...

and a small area of

North Carolina North Carolina () is a state in the Southeastern region of the United States. The state is the 28th largest and 9th-most populous of the United States. It is bordered by Virginia to the north, the Atlantic Ocean to the east, Georgia and So ...

, a region with exceptionally high rainfall.

References

{{Wetlands Appalachian bogs Landforms Wetlands