Gulf Coast Wet Prairie and Savanna

This ecological system of western Florida and adjacent Alabama and Mississippi has been called "lush grassland," "grass-sedge savannah," wet prairie, or wet savanna. As implied by these names, this system consists of primarily herbaceous vegetation with relatively thick cover of grasses and sedge species. Examples occupy low, flat plains on poorly drained soils, often saturated for 50-100 days per year. Frequent fires, including growing-season burns, are essential for maintenance of this system. Some examples have a sparse tree component of Pinus elliottii or Pinus palustris and scattered shrubs, such as Morella caroliniensis.

Collins et al. (2001) documented less than 10 trees per acre (Pinus elliottii and Pinus palustris) in examples of this system on the Apalachicola National Forest. Magnolia virginiana, Acer rubrum, and Morella cerifera are often present in sometimes locally dense patches, especially when managed with infrequent fires (Collins et al. 2001, FNAI 2010a). Aristida beyrichiana, Ctenium aromaticum, Rhexia alifanus, Rhynchospora spp., and Eriocaulon spp. are typical species. This ecological system may be considered a "lush grassland" (Kindell et al. 1997), "grass-sedge savannah" (Clewell 1981), wet prairie (FNAI 2010a), or wet savanna (Collins et al. 2001).

This system occupies low, flat plains on poorly drained Ultisols. Sites are saturated for 50-100 days per year (FNAI 2010a). Other soil orders may include Ultisols, Spodosols, Inceptisols, and Entisols (Collins et al. 2001); some of these soils have an argillic horizon which impedes drainage and contributes to high water tables. On Eglin Air Force Base, this system is found on the Rutledge series (Kindell et al. 1997).

Wet prairies are seasonally inundated or saturated for 50 to 100 days a year (FNAI 2010a). Fire-return intervals have been estimated to be 2-3 years (FNAI 2010a). Wet prairies can be large areas which would have been naturally prone to frequent fire. Today prescribed fire is needed to maintain high-quality examples of wet prairies. Without frequent fire, shrubs and trees can dominate the site, and this leads to a decline in the herbaceous plant diversity.

Prescribed fires, including some growing-season fires, are essential for the maintenance of wet prairies. In the absence of fire, woody plants, including evergreen shrubs and pines, will invade the prairie and competition will reduce the layer of herbaceous vegetation. Wet prairies are also vulnerable to hydrologic changes and soil disturbance. The alteration of hydrology (such as drainage) is a threat because these wetlands depend on natural hydrology. Many wet prairies have been degraded due to disturbances from silviculture, ditching, ORV use, and feral hog (Sus scrofa) foraging activities (Kindell et al. 1997). Roads with significant traffic and, to a lesser extent, powerlines and gaslines reduce the ability to manage savannas and wet prairies with prescribed fire, due to smoke safety concerns. Conversion of nearby areas to suburban development makes the use of prescribed fire in remaining wet prairies and savannas more difficult. Areas drained in the past have been converted to pine plantations, then converted to suburban development such as housing and commercial. Overgrazing by livestock of natural savannas can be a threat. Hogs are especially destructive to these habitats, due to their rooting activities. Conversion to improved pasture with exotic forage grasses is a threat. Prior to the 1900s, cattle breeds such as Florida Cracker and Pineywoods grazed on the native grasses and shrubs in the frequently burned open range, including these savanna and wet prairie habitats. These now rare cattle breeds were descended from cattle brought by the Spanish in the 1500s. The past grazing by these breeds may have been more compatible with the natural wet prairies and savannas than modern cattle grazing. Invasive exotic plants are a threat, including Imperata cylindrica and Triadica sebifera. Poaching of orchids and carnivorous plants is a threat.

Western Florida and adjacent Alabama and Mississippi.