Flood Plains And Seepage Swamps

Description

The reference state includes forests and woodlands with an evergreen shrub stratum and canopy dominated by Pond Pine (Pinus serotina), Atlantic White Cedar (Chamaecyparis thyoides), and/or hardwoods such as Sweet Bay (Magnolia virginiana), Swamp Black Gum (Nyssa biflora), and Tuliptree (Liriodendron tulipifera). The ecological dynamics of the state are influenced by the amount and duration of saturation or flooding and the frequency and intensity of wildland fire. These areas are generally upstream from well developed floodplains, and are more influenced by seepage fed saturation, than by flooding for stream channel overflow. These seepage habitats support many evergreen shrubs which can burn in medium to high intensity wildland fires. The leaves of these shrubs contain volatile oils which provide substantial fuel to fires which may approach this riparian habitat from adjacent uplands at medium intensity. The varied frequency and intensity of wildland fire contributes to a mosaic of different vegetation with in this ecological site.

Submodel

Description

State 2 occurs when frequent burns cause the site to become dominated by herbaceous plants, mostly wetland graminoids or Switch Cane (Arundinaria gigantea ssp. tecta). These treeless seepage wetlands are also found in patches slightly upslope from the Sandhill Streamhead Pocosin and Swamp, and are included as a separate ecological site description document. However, since there is a relationship between the Streamhead Canebrake and Sandhill Seep and the Sandhill Streamhead Pocosin and Swamp, it is included as a state in this state transition model. Streamhead Canebrake and Sandhill Seep which is not subject to wildland fire for a long period of time with succeed to Sandhill Streamhead Pocosin and Swamp. These are sensitive habitats, the disturbance caused by ORV use or hog rooting will lead to a transition to ruderal Wet Meadow and Marsh.

Submodel

Description

Coastal Plain Semi-permanent Impoundment represents areas along creeks or small rivers which may be dammed by beavers or by mill dams. Beavers were one of the first animals to be commercially exploited for the European market. After the beavers were depleted, they had a greatly reduced role in creating and maintaining impoundment ponds. As settlers came into areas, creeks and small rivers were dammed for milling. Today many of the mill ponds no longer exist, but beaver have been making a comeback in recent decades. Both mill ponds and beaver ponds can provide the same type of semi-permanently flooded habitat for aquatic vegetation. With dam failure the Coastal Plain Semi-permanent Impoundment transitions to Wet Meadow or Marsh.

Submodel

Description

Wet Meadow & Marsh habitats are herbaceous wetlands which have been disturbed in some way. When dam failure causes an impounded area to no longer be flooded, then the site becomes available to plants which are quick to colonize the previously impounded area. Generally these are wetland graminoid plants which are typical of ruderal conditions, such as Andropogon glomeratus var. pumilus, Juncus effusus, or Scirpus cyperinus. The invasive exotic shrub, Ligustrum sinense can also become dominant on these newly available sites. When Blackwater Bottomland Hardwoods or Cypress- Gum Swamps are clearcut, these same opportunistic wetland graminoids or exotic shrubs can come to dominate the newly opened and disturbed site. These sites can (in turn) recover to ruderal forests, or can become dominated by the exotic Tallow tree, Triadica sebifera.

Submodel