The Coastal Prairie Region
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The coastal prairie region refers to the habitats that occur within the western gulf coast area and includes the coastal prairie grasslands as well as adjacent and included coastal wetlands and gallery forests . Ecological conditions within the coastal prairie region vary from the coast inland and from east to west with major gradients in hydric, saline, and climatic features. Additional references on the features of this region can be found in the general bibliography.
Natural prairie is dominated by long-lived perennials which form a dense mat of intertwined roots. With the exception of partridge pea (Cassia fasciculata), false foxglove (Agalinis sp.) and a few others, annuals are rare in undisturbed prairie sod. In Midwestern tallgrass prairie, disturbances are rapidly recolonized vegetatively by surrounding plants. Seed is thought to be only of occasional importance in the recruitment of species to new areas of prairie. It is not yet clear what role seed recruitment plays in the coastal prairie.
Despite the small size of the Cajun (Louisiana) prairie remnants, they contain a high diversity of native tallgrass prairie flora. Big bluestem, Indiangrass, and switchgrass (Panicum virgatum) dominate these remnants just as they dominate the prairie of the Midwest. Because coastal prairie grades into coastal marsh the southern most prairies often have shallow standing water and are often dominated by switchgrass and eastern gammagrass.
Many wildflowers common on prairies of Iowa and Illinois are also found on the Cajun prairie. An obligate prairie species in our area, Eryngium yuccifolium (see picture at right), is a noted indicator of moist prairie from Minnesota to Texas. Eryngium yuccifolium is very common in Cajun prairie as are such northern prairie species as Kansas gayfeather (Liatris pycnostachya) and blackeyed susan (Rudbeckia hirta).
Traveling west into the coastal prairie of Texas, western species appear such as sideoats gramma (Bouteloua curtipendula), prairie coneflower (Ratibida columnaris), and small patches of prairie cordgrass (Spartina pectinata). Near the Texas coast prairie grades into high salt marsh, producing a unique prairie type called salty prairie, dominated by gulf cordgrass (Spartina spartinae). These Texas remnants face the same problems as those in Louisiana: many of the unique areas of prairie are being destroyed by development.
While the coastal prairie contains a great deal of vegetation common with the central and northern "true prairie," there are some plants in the coastal prairie community that are only found in this system. One such endemic is the prairienymph (Herbertia lahue var. cerulea). The prairienymph is a member of the iris family and is fairly common in the prairies of Texas though rare in the adjoining Cajun prairie. Its rarity may be due to the severe loss of habitat in Louisiana and possibly also from a reduction of native pollinators.
Other southern prairie natives ashy sunflower (Helianthus mollis) and slender bluestem (Schizachyrium tenerum) also occur in long-leaf pine understory of Southern states. Brown-seed paspalum (Paspalum plicatulum), restricted to coastal states can be a dominant in wet prairies of Texas and Louisiana, possibly because it is an increaser on sites with heavy grazing.
Among the most serious problem facing prairie remnants and restorations is invasion by exotic plants. Two of the most problematic invaders are Macartney rose (Rosa bracteata) and Chinese tallow tree (Triadica sebiferum). Both species rapidly invade abandoned farm land and also easily colonize overgrazed fields. While their ability to colonize intact prairie is apparently slow, it does occur over time. These invading species are root sprouters, giving them the ability to readily management by early spring fire. Annual growing season burns appear can be effective if sufficient fuel and burn conditions exist.
There has also been a proliferation of native woody plants such as eastern baccharis (Baccharis halimifolia) and wax myrtle (Myrica cerifera) in the absence of fire. Where fire has been reinstated as a management tool, Baccharis infested prairies recover with little loss of diversity. However, in prairies reclaimed from Chinese tallow infestations, herbaceous communities do not recover. When fire management is applied to native prairies with a history of heavy grazing, herbaceous ground cover lack the plant diversity typical of remnant prairies. These reclaimed prairies, chiefly in Texas, are composed primarily of little bluestem (Schizachyrium scoparium) and very few other grasses or wildflowers. Methods for reintroducing grasses and forbs to depauporate remnants and restorations are needed.
Prairie restoration is gaining interest in parts of Texas and Louisiana as well as in parts of the Midwest. Methods vary between geographical areas and individual restorationists, and success varies from year to year. Planting a restoration involves (1) preparation by herbicide, solarization, or tillage; (2) planting by haying, seeding, sodding, or transplanting; and (3) management by mowing, irrigation, grazing, and fire. The best time for planting varies based on location and method.
There are no simple answers to the question of how we may best preserve a diverse and functioning coastal prairie. Restoration on public land and by concerned citizens on private land and continued research on restoration technology, ecosystem health and control of invasive exotics are crucial if this most endangered community type is to be preserved.
Prairie restoration is gaining interest in parts of Texas and Louisiana as well as in parts of the Midwest. Methods vary between geographical areas and individual restorationists, and success varies from year to year. Planting a restoration involves (1) preparation by herbicide, solarization, or tillage; (2) planting by haying, seeding, sodding, or reintroduction; and (3) management by mowing, irrigation, grazing, and fire. The best time for planting varies based on location and method.