Jennifer Hales. Description includes text adapted from Abell et al. 2000. Freshwater Ecoregions of North America: A Conservation Assessment. Island Press, Washington, DC, USA.


United States

Major Habitat Type

Temperate upland rivers

Drainages flowing into

The Cumberland River drains to the larger Mississippi Basin by way of the Ohio River.

Main rivers to other water bodies

In the northern portion of the ecoregion, the mainstem Cumberland River originates at the confluence of the Poor and Clover forks; in total, the Cumberland drains more than 46,000 km2 before joining the Ohio River at Smithland, Kentucky (Ono et al. 1983). Tributaries to the Cumberland include the Big South Fork, Rockcastle, and Little rivers. 

Although the Tennessee and Cumberland rivers flow quite close to each other near their confluence with the Ohio, they were not physically linked historically. Today, dam construction on both rivers has changed this situation. The construction of Barkley Dam impounded the Cumberland, forming Lake Barkley, while just a few miles away the Kentucky Dam was built to impound the Tennessee River, thereby creating Kentucky Lake. This alone was not enough to link the two reservoirs, so a channel was cut not far from the head of each lake to link them together. Other mainstem and tributary reservoirs constructed by the Tennessee Valley Authority for flood storage and power generation are also major surface water features.



The ecoregion is defined by the watershed of the Cumberland River, which drains to the larger Mississippi Basin. The ecoregion borders Tennessee and Kentucky, covering much of southern Kentucky and north-central Tennessee.


The topography of the ecoregion is diverse, with valleys, ridges, and falls downcut by major streams. Topographical features include the Highland Rim, a crater rising 250 – 300 m that encircles the Nashville basin. It is characterized by deep channels incised by the lower Cumberland River. Rising 300- 900 m altitude in the east lies the Cumberland Plateau, which consists of sandstones, shales and coals. Here, falls have formed over resistant sandstone substrates, with Cumberland Falls being the most notable (Starnes & Etnier 1986).

Freshwater habitats

The region’s physiographic and geological diversity accounts for much of the faunal diversity of the ecoregion. The Highland Rim is characterized by numerous caves, springs, surface streams, falls, and a labyrinth of subterranean channels. Streambeds of the Nashville basin are typically low gradient, meandering, and highly productive. Except for the headwaters of the Cumberland, which drain the steep slopes of the Cumberland Mountains, streams of the Cumberland Plateau are generally incised, meandering, with low productivity (Starnes & Etnier 1986).

Terrestrial habitats

The western half of the ecoregion is characterized by deciduous broadleaf forests, dominated by oak-hickory communities. Appalachian mixed mesophytic forests are the dominant communities on the eastern side of the ecoregion. These relict stands were once widespread across temperate North America, and served as mesic refuges during drier glacial periods (Ricketts et al. 1999).

Description of endemic fishes

Species endemic to the ecoregion include a couple of darters (Etheostoma forbesi and E. luteovinctum), two shiners (Notropis albizonatus and N. rupestris), blotched chub (Erimystax insignis), barrens topminnow (Fundulus julisia) and the blackside dace (Phoxinus cumberlandensis), which is restricted to the upper Cumberland drainage above Big South Fork (Starnes & Etnier 1986).

Justification for delineation

Ecoregion boundaries are modified from Abell et al. (2000), which based its units on subregions defined by Maxwell et al. (1995). Modifications to this ecoregion were made following recommendations from the Endangered Species Committee of the American Fisheries Society. Based on faunal data from Hocutt & Wiley (1986), the Endangered Species Committee decided there was a significant number of species exclusively endemic to the Cumberland [151] and Tennessee [152] drainages to warrant separate ecoregions. 


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