Southeastern Rivers and Streams - A Global Ecoregion
One of the most species-rich temperate freshwater areas
Snapshot: Ecoregion 175
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
Quiz Time!
What is the Lake sturgeon known for?
Answer:
The lake sturgeon has been reintroduced in the French Broad reach of the Tennessee River, near Knoxville. This fish species, which can grow to be over 8 feet (2.4 meters) and 136 kgs, can live up to 100 years. It was one abundant in the Tennessee River, but was extirpated due to waste pollution.
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.
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.
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).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.
Resources
• NationalGeographic.com
