Common (Translated Scientific) Name: Switchgrass - Eastern Gamagrass - (Maidencane) Grassland

Colloquial Name: Wet Coastal Prairie

Hierarchy Level:  Association

Type Concept: This association describes wet coastal prairie, now virtually extirpated, that historically was found in a natural mosaic with upland, mesic (non-wetland) coastal prairie to form the once extensive coastal prairies of the Pleistocene Prairie Terraces of southwestern Louisiana and southeastern Texas. This type occupied the broad low flats, drainage swales (locally called "coulees" in Louisiana), and small shallow seasonally flooded areas (often called "marais" and "platins") that interdigitated with the slightly higher broad, convex flats of upland coastal prairie. It also occupied low, wet areas between pimple mounds, the mounds supporting upland coastal prairie. This landscape was bisected by "gallery forests" along small permanent streams that divided the prairie into "coves." The prairies unquestionably sustained a rich variety of wetland grasses, sedges, rushes and forbs. Extremely few examples of wet coastal prairie remain, and practically no historical literature records of the vegetation were made. Further estimations of the characteristic vegetation of this type, primarily in relation to Louisiana examples, have been developed from a review of heliophytic herbaceous wetland vegetation thought to be native to the region, combined with the few floristic studies made of remnant native "prairie" patches in the area. Grasses and grass-like plants (graminoids) most likely dominated. It must be noted that the coastal prairie vegetation of this type in Louisiana is very much like that of the adjacent longleaf pine flatwood savannas. The coastal prairie grades gradually on its northern edge into the longleaf pine flatwoods section in Louisiana, the two types sharing most herbaceous species in common in the transitional area. The soils of wet coastal prairie are hydric, strongly acidic to slightly alkaline, and are mainly silt loams and silty clay loams. The coastal prairie zone of southwestern Louisiana and southeastern Texas has become very seriously infested with Triadica sebifera, which in many places has formed dense thickets and forests. It will quickly dominate fallow pastures and fields. Historically, upland coastal prairie was maintained by frequent burning and soil conditions generally inhospitable to the growth of trees and shrubs.

Diagnostic Characteristics: No Data Available

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: Essentially all of the prairie has long been completely altered from its native condition, mainly for agriculture, but early accounts state that these areas were essentially treeless and supported luxuriant prairie. Much of the wet prairie has gone into rice cultivation. Marais and platins deserve special mention as unique, small, often rain-flooded wetlands of the coastal prairies. Once quite numerous, particularly in the eastern prairie (Kniffen 1968), they typically ranged in size from less than an acre, up to several acres. Newton (1987) has described marais as a boggy, swampy tract of land up to 10 acres in size that becomes an irregular pond after rains, and described platins as roundish ponds about 30 m (100 feet) in diameter. Taylor (1956) stated that such depressions ranged from 1 to 2 feet deep, had quite steep sides, and were essentially level-bottomed. The origin of platins (in the sense of Newton) remains a mystery (some believe old buffalo or cattle wallows), while marais ponds may represent incompletely filled relict stream channels. A few examples of these small seasonal ponds dominated by herbaceous plants still remain, although the floristic complement is no doubt highly altered. This type was modified to incorporate slightly different examples in southeastern Texas, where Panicum hemitomon is replaced by Panicum virgatum on intermound areas and old meander scars on Vertisols and Alfisols. Further classification work is needed to refine this concept. See also ~Tripsacum dactyloides - Panicum virgatum - Sorghastrum nutans - Helianthus maximiliani Grassland (CEGL002217)$$.

Similar NVC Types: No Data Available

note: No Data Available