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# of Endemic Species
525: Ethiopian Highlands
Major Habitat Type:
Abebe Getahun, Department of Biology, Addis Ababa University, Addis Ababa, Ethiopia
Eritrea; Ethiopia; Somalia
This high-altitude ecoregion is defined by the two blocks of highlands in Ethiopia, separated by the rift valley and distinguished by a freshwater fauna adapted to the ecoregion’s swift-flowing rivers. The highlands extend from
Drainages flowing into:
Rivers of the western highlands generally flow towards
Main rivers or other water bodies:
In the northwestern part of the highlands, the deep, steep-sided valleys of the major rivers separate blocks of mountains, and the upper courses of the big rivers such as the Tekezze and Abay (
The westward flowing rivers (the Tekezze, Angereb,
According to Westphall (1975), uplift of the Ethiopian highlands together with Arabia occurred on an extensive scale after the regression of the Red Sea towards the southeast in the late Mesozoic to early Tertiary. The
The Ethiopian highlands receive about 950 mm or more of rainfall due to a double passage of the intertropical convergence zone. The high mountains east of
The fishes of the high mountain torrential streams are largely cyprinids (Harrison 1995; Getahun & Stiassny 1998) adapted to the swiftly flowing floodwaters that occur seasonally. Two genera of fishes (Barbus and Garra) dominate the fish fauna of these streams. Clarias gariepinus, Varicorhinus beso and Labeo spp. are also found in high numbers. The Baro-Akobo basin is apparently particularly rich in fish diversity (Golubtsov et al. 1995). The fauna is Nilo-Sudanic and is dominated by Alestes, Bagrus, Barilius, Citharinus, Hydrocynus, Hyperopisus, Labeo, Malapterurus, and Mormyrus genera.
Description of endemic fishes:
Endemism appears to be high among fish, but the fish fauna is not well known. Endemic fishes of the genus Garra (e.g. G. dembecha, G. duobarbis and G. ignestii) have recently been described (Getahun 2000). Lake Hayq is believed to have no indigenous fish species, although the presence of Clarias gariepinus has been reported (Beckingham and Huntingford in Kebede et al. 1992). Nemacheilus abyssinicus is an endemic species found in the Baro-Akobo drainage basin, the Omo-Gibe drainage basin, and
Other noteworthy fishes:
Other noteworthy aquatic biotic elements:
The invertebrate fauna is less well known than the fishes and it is difficult to estimate endemism among the aquatic invertebrates. Harrison and Hynes (Harrison & Hynes 1988)(Harrison and Hynes 198 indicated that Dugesia spp., Baetis harrisoni, Pseudocloeon sp., Centroptilum sudafricanus, Afronorus peringueyi, Neoperla spp., Hydropsyche sp., Simulium spp., nymphs of Aeschna, and chironomid larvae dominate the benthic communities in the stony runs and torrents of the Ethiopian highlands. Compared to other highland ecoregions, the Ethiopian Highlands support a rich aquatic mollusc fauna with over 20 species described.
Justification for delineation:
Despite the fact that the Ethiopian highlands are presently separated from both the East African and the South Arabian mountains, the riverine fauna resembles that of east and southern Africa (Tudorancea et al. 1999), along with some elements of the Arabian Peninsula. Cyprinids are the dominant fish in the rivers of this ecoregion. For example, it is known that some small Barbus species (e.g., Barbus paludinosus, B. trimaculatus and B. radiatus) have widespread distributions extending from South Africa to East Africa and into the highlands (Skelton et al. 1991). There are also fish groups (e.g. Garra) common to the Ethiopian highlands and the
Level of taxonomic exploration:
Fair. Historically, few scientific studies have been made on the fauna of the river systems of Ethiopia; however, two recent studies have elevated the level of data available for the fish of this ecoregion (Getahun & Stiassny 1998; Golubstov et al. 2002). River systems in the Tekezze-Angereb basin have not been studied at all due to security problems in the past. Preliminary reports indicate that the large river bodies of this basin support a rich fish fauna and research is needed to confirm this. Some information on the benthic fauna of Ethiopian mountain streams and rivers is available in Harrison and Hynes (1988).
Beadle, L. C. (1981). "The inland waters of tropical Africa" England: Longman Group Limited.
Briggs, J. C. (1987). "Biogeography and plate tectonics" Amsterdam, The Netherlands: Elsevier.
Getahun, A. (1998)"The Red Sea as an extension of the Indian Ocean" In Sherman, K.;Okemwa, E.N.;Ntiba, M.J. (Ed.). Large marine ecosystems of the Indian Ocean: Assessment, sustainability, and management. (pp. 277-281) Cambridge, MA, USA: Blackwell Science.
Getahun, A. (2000) "Systematic studies of the African species of the genus Garra (Pisces: Cyprinidae). Unpublished PhD thesis". New York, USA. The City University of New York.
Getahun, A.,Stiassny, M. L. J. (1998). "The freshwater biodiversity crisis: The case for conservation" Ethiopian Journal of Science 21(2) 207-230.
Harrison, A. D. (1995)"Northeastern Africa rivers and streams" In Cushing, C.E.;Cummings, K.W.;Minshall, G.W. (Ed.). River and stream ecosystems. (pp. 507-517) Netherlands: Elsevier Science B. V..
Harrison, A. D.,Hynes, H. B. N. (1988). "Benthic fauna of Ethiopian mountain streams and rivers" Archiv für Hydrobiologie/ Supplement 81 1-36.
Kebede, E., Teferra, G., et al. (1992). "Eutrophication of Lake Hayq in the Ethiopian highlands" Journal of Plankton Research 14(10) 1473-1482.
Skelton, P. H., Tweddle, D., et al. (1991)"Cyprinids of Africa" In Winfield, I.J.;Nelson, J.S. (Ed.). Cyprinid fishes: systematics, biology and exploitation. (pp. 211-239) London, UK: Chapman and Hall.
Tudorancea, C., GebreMariam, Z., et al. (1999)"Limnology in Ethiopia" In Wetzel, R.G.;Gopal, B. (Ed.). Limnology in developing countries, 2. (pp. 63-118) New Delhi, India: International Association for Limnology.
Westphal, E. (1975). "Agriculture systems in Ethiopia. Joint publication of the College of Agriculture, Haile Selassie I University, Ethiopia and the Agricultural University, Wageningen, The Netherlands"
Wood, R. B.,Talling, J. F. (1988). "Chemical and algal relationships in a salinity series of Ethiopian inland waters" Hydrobiologia 158 29-67.