K Kafue Flats been greatly regulated following the construction of two large dams at opposite ends of the biome in Category: Inland Aquatic Biomes. the 1970s. These dams have markedly altered the Geographic Location: Africa. ecological dynamics, leading to declined popula- Summary: Kafue Flats is one of Africa’s largest tions of at least some ungulates. wetlands and among the richest wildlife areas in the world. Dam construction and operation is Geography and Hydrology causing population declines among some species. The ecosystem is located midway along the Kafue River, a major tributary of the Zambezi. It occupies One of the most studied and unique riverine eco- a low-lying plain in Zambia, stretching about 158 systems, Kafue Flats is an extensive floodplain miles (255 kilometers) long and 25–37 miles (40– characterized by cyclically inundated grass-sedge 60 kilometers) wide, and covering approximately associations, expansive lagoons, reed marshes, and 2,510 square miles (6,500 square kilometers). oxbow lakes. The ecosystem ranks among Africa’s With rainfall averaging less than 31 inches (800 largest wetlands and the world’s richest wild- millimeters) per year, moisture is sustained mainly life areas. It is especially famous for the endemic by direct rainfall in the upper river catchment, (found nowhere else) Kafue lechwe (Kobus lechwe where precipitation is much heavier. Maximum kafuensis) antelope species, and as well an abun- inundation occurs with a time lag of up to several dance of waterbirds, including large aggrega- weeks after peak rainfall in the catchment, reach- tions of the wattled crane (Grus carunculatus). ing a peak from April to June, although this pattern Within the landscape lie two parks that constitute varies considerably from year to year. Water may a Ramsar Wetlands of International Importance take up to two months to pass through the gentle site, owing to the parks’ importance for resident profile, whose elevation drops by only 20–33 feet and migratory species. (6–10 meters) along its entire length. Human impact here is considerable. The river Soils are predominantly alluvial clays, with supports a large human population, tourism, and hydrology varying considerably from high mois- hydroelectric power generation. Water flow has ture content most of the year in the finer clays, to 715 716 Kafue Flats less waterlogged in the more coarse clays. Hard tion downstream at the Kafue Gorge, Zambia’s pans up to 12 inches (300 millimeters) or more in primary power source. depth occur on the outer margins at the end of the Other large mammals on the floodplain and in dry season. the adjacent woodlands include the hippopota- mus (Hippopotamus amphibious), blue wildebeest Vegetation (Connochaetes taurinus), Burchell’s zebra (Equus The general vegetation is a diverse mosaic of burchelli), African buffalo (Syncerus caffer), and woodlands interspersed with miombo trees and greater kudu (Tragelaphus strepsiceros). Smaller shrubs such as acacia and bushwillows; the legume ungulates include the sitatunga (Tragelaphus spe- mopane tree; and grasslands characterized by spe- kei), southern reedbuck (Redunca arundinum), cies such as Vossia cuspidata and Oryza barthii, and oribi (Ourebia ourebi). Some carnivores as well as representative species of Hyperrhenia, reside permanently in the area, including the spot- Setaria, Cyperus, and Typha. ted hyena (Crocuta crocuta), lion (Panthera leo), A variety of aquatic plants predominate in the serval cat (Felis serval), and side-striped jackal open water, including the blue water lily (Nym- (Canis adustis), while the wild dog (Lycaon pictus) phaea capensis), pondweed (Potamogeton spp.), visits occasionally. and water hyacinth (Eichhornia crassipes), the last The Kafue Flats biome hosts the greatest abun- being a potentially serious invasive. Floating mats dance of waterbirds in Zambia, including large often occur as a result of breakoffs from aquatic aggregations of the wattled crane, one of the and semiaquatic riverine vegetation on the banks. most threatened birds and the largest and rarest The structure and composition of vegetation of the six crane species in Africa. Other notable within the immediate vicinity of the river depend birds include the vulnerable slaty egret (Egretta largely on soil type and topography. Primary pro- vinaceigula) and long-tailed cormorant (Phala- ductivity here is much higher than in the more crocorax africanus). With more than 400 migra- nutrient-poor soils further away from the river. tory bird species estimated to pass through each The transition to woodland above the permanent year, the area has been designated an Important floodline, with scattered trees and shrubs domi- Bird Area. nated by Termitaria, is closely associated with More than 50 fish species have been recorded, conspicuous termite mounds and some common some of which are endemic to southern Africa, woody shrub weeds such as Mimosa pigra. including the Kafue killifish Nothobranchius( kaf- uensis). Some migrate locally out onto the flood- Fauna plains, taking advantage of increased habitat and Kafue Flats is a globally unique wildlife paradise, protective vegetative cover. containing numerous mammal and bird species, Lochinvar and Blue Lagoon National Parks, some of which remain permanently, while oth- located on the south and north banks of the ers migrate as part of their annual cycles and in river, respectively, have been recognized for their response to drought or food scarcity elsewhere. importance as wetlands and habitat for resident About half of all the remaining lechwe (Kobus and migratory birds. They form part of the Kafue lechwe) in Africa are found here. However, the Flats Ramsar site. population for the endemic Kafue lechwe, one of three key subspecies, is estimated to have Effects of Human Activity declined from about 100,000 in the 1970s to fewer More than 1.3 million people live within the than 40,000 now. This decline is attributed largely wider watershed, about 25 percent of whom rely to changes in the flooding regime occasioned by directly on the wetlands for their livelihoods in construction of the Itezhi-Tezhi dam, which is cattle grazing, hunting, fishing, and tourism. used for storage of peak-season flows. The storage Sugar-cane irrigation and processing causes efflu- is undertaken to maximize hydropower produc- ent discharges back into the river, causing nutri- Kakadu Wetlands 717 ernmental agencies that are committed to devel- oping coordinated programs to rehabilitate the environment and its resources. Evans Mwangi Further Reading Fishpool, L. D. C. and M. I. Evans, eds. Important Bird Areas in Africa and Associated Islands: Priority Sites for Conservation. Ormond Beach, FL: Pisces Publications, 2001. Mumba, M. and J. R. Thompson. “Hydrological and Ecological Impacts of Dams on the Kafue Flats Floodplain System, Southern Zambia.” Physics and Chemistry of the Earth 30, no. 6–7 (2005). Smardon, R. C. Sustaining the World’s Wetlands: Setting Policy and Resolving Conflicts. New York: Springer, 2009. Thieme, M. L. Freshwater Ecoregions of Africa and Madagascar: A Conservation Assessment. A Kafue lechwe, which is endemic to the Kafue flats area. Washington, DC: Island Press, 2005. Its population is thought to have fallen from as many as 100,000 in the 1970s to less than 40,000 today. (Thinkstock) Kakadu Wetlands ent enrichment and invasive plant growth, clog- ging the waterway, and suffocating fish. Animal Category: Inland Aquatic Biomes. poaching and overfishing are problems, as is,the Geographic Location: Australia. elimination of peak floods and some extreme Summary: Kakadu contains more than 10,000 drought conditions, due to uneven water manage- insect species, in excess of 280 bird species, 117 ment of the area’s two dams. kinds of reptiles, 60 mammals, 53 freshwater fish, As effects of global warming—both those and more than 1,700 plant types. already detected, and the potential future ramifi- cations to temperature, precipitation, air currents, The Kakadu Wetlands has been called a climate and seasonal onsets—become better understood, change hotspot. Situated in the Alligator Riv- it is clear that human interaction with the hydro- ers region of Australia’s Northern Territory, the logical cycle here will become an even sharper Kakadu Wetlands has a tropical monsoonal cli- instrument that can enhance or harm these wet- mate. Humidity is low and rain rare in the dry sea- lands and their dependent species. son (April to September). Build-up or transition The human interference of the natural wet and months include high temperature and high humid- dry cycles has already disrupted fish reproductive ity, with violent lightning storms. The rainy season cycles, and affected the birds and local population is from January to March and sometimes April; it that depend on these fish. As a result, species have is both warm and wet. Rainfall in Kakadu averages been lost as the wetland habitat has degraded. 51–61 inches (1,300–1,565 millimeters) per year. Conservation programs have been undertaken by The Kakadu Wetlands biome is part of an exten- local communities, governmental and non-gov- sive network of habitats here that feature stone .