Southeastern Rivers and Streams

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Everglades National Park, Florida, USA.
© WWF-Canon / Martin HARVEY

About the Area

From its clear, cool streams in the Appalachian Mountains to its brackish marshes along the Atlantic and Gulf coasts, this freshwater ecoregion, covering nearly 10 per cent of the United States, includes a wide variety of habitats and some of the most species-rich freshwater systems in the world.

The rivers and streams of the American Southeast are unusually rich in aquatic biodiversity. They are home to such colorfully named fish as the Pygmy Madtom (the world's smallest catfish), the Halloween Darter, and mussels like the Tennessee Heelsplitter and the Purple Wartyback.

It is home to hundreds of species of fish, snails, mussels and other invertebrates. Within the Roanoke River basin alone, more than 200 fish species are found, of which six are endemic.

One of few natural lakes in the Southeast United States, Lake Waccamaw was likely formed by a meteoric impact and harbours several endemic fish - a highly unusual evolutionary phenomenon.
Size:
640,000 sq. km (250,000 sq. miles)

Habitat type:
Small Rivers

Geographic Location:
Southeastern North America: from southern Virginia west to Tennessee and south to Alabama and Florida

Conservation Status:
Critical/Endangered
Local Species
Of the roughly 400 species of crayfish in the United States, about 70 percent are found only in Southeastern Rivers and Streams. A relatively intact stream in this region supports more mussel species than all of Australia and Europe combined. In just one river, the Cahaba in Alabama, there are more fish species per kilometer than any other river in North America, including 18 species that exist nowhere else.

Fish species include local endemics such as Waccamaw silverside (Menidia extensa), Waccamaw killifish (Fundulus waccamensis), and Waccamaw darter (Etheostoma perlongum).

Numerous other fishes found in the ecoregions streams include Cyprinids - e.g, fieryback shiner (Cyprinella pyrrohmela), Redlip shiner (Notropis chiliticus), Blackmouth shiner (Notropis melanostomus), Blacktip shiner (Lythrurus atrapiculus).

And, Darters such as, Choctawhatchee darter (E. davisoni), Southern logperch (Percina autroperca), Florida sand darter (Etheostoma bifascia), Okaloosa darter (E. okaloosae); Suckers like, greater Jumprock (Moxostoma lachneri), Grayfin redhorse (Moxostoma sp.); and larger species like Alligator gar (Atractosteus spatula).

Aquatic species other than fish include the Mabee's salamander (Ambystoma mabeei), Dwarf waterdog (Necturus punctatus), Neuse River waterdog (N. lewisi), Ringed map turtle (Graptemys oculifera), Everglades's crayfish (Procambarus alleni), and Florida applesnail (Pomacea paludosa).

Featured species

Dwarf waterdog (Necturus punctatus)

This is the smallest of the waterdogs, ranging from 11 - 16 cm (4.5 to 6.5 in). It has internal fertilization and probably lays eggs in the spring.

The Dwarf Waterdog is completely aquatic. It is an opportunistic feeder and will eat crayfish, aquatic insects, and worms. It is found where leaves and similar debris cover the bottom, in black-water and slow-moving streams, swamps, flooded fields, and irrigation ditches. There are no truly conspicuous markings that aid in diagnosis. In general, the coloration is gray to blue to brown to black with small nondescript spots.

The Dwarf Waterdog has obvious external gills, and has four toes on each foot. It has internal fertilization and probably lays eggs in the spring. It is found from the Atlantic Coastal Plain to the Fall Line and west throughout the Altamaha River drainage.

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Threats
This ecoregion is in one of the most highly populated areas in the United States, and it is rapidly growing. Despite the fact that this is a well-watered region, humans are competing with aquatic species for water. Interbasin water transfers and dams are prevalent, and new projects being planned. Aquatic habitats are further modified through widespread channelisation.

Pollution from acid rain, deforestation, roads, agriculture, urbanisation, and industrialisation places additional stresses on native species. Introduction of non-native species like Asiatic clam (Corbicula fluminea) and Zebra mussel (Dreissena polymorpha) threaten native mussel populations, and exotic fish pose similar threats to native fish.
WWF’s work
Both the U.S. House and Senate have passed budget reconciliation bills that would seriously cut funding for programs that encourage farmers to practice conservation measures. WWF activists in Tennessee spoke out loudly in support of these programs, sending 819 letters sent to Congress in the fall of 2005.

Federal agriculture conservation programs encourage farmers to preserve open space, protect wildlife habitat, reduce pesticide use, and improve water and air quality. These programs are on the chopping block as lawmakers struggle to find savings in order to reduce the federal deficit. However, these vitally important and highly effective programs have already been heavily cut over the last few years and are unable to meet the demand from farmers who want to participate.

With further cuts, some of Tennessee’s most pressing public health and environmental challenges, such as deteriorating water quality, will continue to go unmet. Poor water quality will take a huge toll on the unusually rich aquatic biodiversity found in Tennessee's rivers and streams and throughout the southeastern United States. More than 250 species of crayfish, nearly 300 species of mussels, and over half of all freshwater fish species in the United States are found in the waters of the Southeast. Many native species are found in just one stream or watershed in this region and nowhere else on the continent.

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