Mississippi Sandhill Crane National Wildlife Refuge
Conserving the Nature of America
Unique Habitats

Cranes Flying through Savanna

The refuge's vegetation communities are a mosaic of pine savannas and pinelands interspersed with wooden swamps and drainages, along with a small tract of estuarine marsh. These plant communities have also been called "coastal prairies", "pine barrens", "wet prairies", "pitcher plant bogs", and "cypress flats".

The area is characterized by high rainfall, flat topography and poorly drained, acidic, nutrient-poor soils with a perched water table due to a subsurface clay hard pan. All the terrestrial plant communities have been shaped by frequent surface fires. Fire has suppressed the growth of woody vegetation and stimulated the germination and even flowering of plant species, such as bunch grasses. (Read more about how the refuge simulates natural fire cycles)

All those features make the Mississippi Sandhill Crane NWR a wonderland of species diversity.

Pine Savanna

Pine savannas are open, nearly treeless, fire-dependent plant communities dominated by well-developed ground cover and some low-growing shrubs with only scattered trees. The refuge is approx. 5216 acres pine savanna.

The original presettlement vegetation on what is now the refuge consisted mostly of pine savannas. Over time, fire suppression allowed pines and shrubs to invade and out-compete the native savanna plants.

In the 1960s and 1970s, much of the remaining open savanna was converted to pine plantation by planting and ditching, which disrupted the natural water regime.

The ground-level plant community is highly species-rich - one of the highest in North America. Of special interest are the orchids and many carnivorous plants.

Savanna


Less than 5% of the original acreage of this habitat remains in the Atlantic/Gulf Coastal Plain, making it one of the most endangered ecosystems in the country. The refuge savannas are considered the last remaining large patches.

Wet Pine Savanna

The difference between mesic and wet pine savannas is simply a matter of moisture. Found on hydric soils, poorly drained with long periods (days or weeks) of soil saturation, the wet pine savanna soil is generally wet at the surface. They contain widely-spaced pond cypress and sometimes swamp tupelo, slash pine and other hydric trees.

Carnivorous plants can be found in this area where the ground is saturated, but not flooded.

Saw Palmetto in a Flatwood



Pine Flatwoods

Pine flatwoods are open, park-like pine woodlands dominated by a low and species ground cover. The refuge is approx. 11,860 acres of pinelands (flatwoods and scrub).

It has been asserted that the only difference between the flatwoods and the savanna is that savannas are clearcut flatlands.

A major management objective at the Refuge is to convert flatwoods to savannas.

Scattered longleaf pine and clumps of saw palmetto are considered conspicuous, but not abundant. Bluejack oak, shrubs and woody vines are also present in the dryer areas.


Pine Scrub

These areas are overgrown with woody vegetation due to silviculture and/or fire suppression. Brush is dominant.

 

Swamps

These are forested wetlands that occupy low-gradient drains through the savannas. Soils are full of organic matter and stream flow is diffuse. The Refuge is approx. 1354 acres swamp/drain.

Vegetation is dominated by mid and over story trees, with a shrub layer and sparce herbaceous groundcover dominated by sedges and even peat moss mats and ferns.

Pond cypress, swamp tupelo, red maple and sweet bay are common trees in the overstory. Bottomland oaks and sweetgum may also be found.

Shallow cypress ponds are common places for crane nests.

Estuarine or Tidal Marsh

Tidal marsh comprises most of the Refuge's Dees Tract in the intertidal zone of Bluff Creek and Bayou Castelle. The water is fresh or slightly brackish. Approx. 581 acres of refuge are classified as estuaries.

Nearer the coast, in the Davis Bayou area, saltmeadow cordgrass and black needlerush dominate in the more saline conditions.

Cypress Swamp


Agricultural Areas


Approx. 860 acres of agricultural areas are on the refuge. These are food plots or crop units, pastures and wastewater spray fields. They have very few to no trees, scattered shrubs and are dominated by the planted crops.

 

   
Last updated: July 23, 2010