Boundaries

The Upper Congo Rapids ecoregion lies entirely within the Democratic Republic of Congo and extends downstream from near the city of Ubundu. Among the many rapids found in the ecoregion are the Tshungu rapids below Ubundu, the rapids near Wanie-Rukula, and the seven cataracts of Boyoma Falls near Kisangani, formerly called “Stanley Falls.” Several rapids also occur along the Lindi, Tshopo, and Maiko Rivers before they meet the Congo (Hughes & Hughes 1992), and a number of prominent islands lie in the middle of the Congo. Although the biota of the ecoregion has not been studied in detail in recent years, a rich fish fauna is known to inhabit the various rapids. 

Terrestrial habitats

The vegetation of this ecoregion, similar to that of the Central Congo, consists primarily of high tropical rainforest with a canopy that reaches up to 45 m high (Hughes & Hughes 1992). Allochthonous inputs from riparian vegetation provide an important source of organic matter for aquatic food webs (Bailey 1986). 

Justification for delineation

The Congo basin lies within an ancient continental lake basin (Beadle 1981). The steep sections of the Congo River, including the rapids of this ecoregion, are thought to have been formed by river capture of the upper Lualaba by the Congo (Marlier 1973). These rapids most likely create a barrier to the movement of some fish species from the Congo River up into the Lualaba. This ecoregion is defined by the rapids of the upper Congo River between Ubundu and Kisangani and is distinguished by an aquatic fauna adapted to life in the rapids.

Level of taxonomic exploration

Poor. Current surveys of the freshwater fauna are needed for this ecoregion.