Effects of Human Activities on Zambia's Kafue Flats Ecosystems By

Effects of Human Activities on Zambia's Kafue Flats Ecosystems by WALTER A. SHEPPE, Ph.D. (British Columbia) Professor of Biology, University of Akron, Akron, Ohio 44325, USA. INTRODUCTION cover of low grasses and was being invaded by woody plants. There were few birds, relatively few Lechwe, and no In May 1967, on the edge of Zambia's Kafue Flats, the other large ungulates (Fig. 2). extensive annual floods were largely hidden by a dense These changes and others in the Kafue River basin are growth of emergent grasses reaching to the horizon. Large the result of a variety of natural or human influences, the herds of Lechwe (Kobus lee he) grazed on the higher ground most important of which was the construction of hydro- around the floodplain and out into the shallow floodwaters. electric dams on the Kafue above and below the Flats. Smaller numbers of Zebra (Equus burchelli), Wildebeest These influences have already caused marked environ- {Connochaetes taurinus), and other ungulates, fed on the mental changes and their long-term effect may be to des- high ground. One of the world's greatest agglomerations of troy much of the rich variety of communities that once avian biomass occupied the floodwaters and the shore occurred along the River. (Fig. 1). This report is based on a twelve-months' study in 1967- . ..; . T*1 *'** " •• ,•' T1 ";»•'•; :* FIG. 1. The edge of the high flood in Lochinvar National Park in May 1967, before construction of the dams. Plentiful Lechwe are feeding in the background on emergent floodplain vegetation and numbers of White Pelicans (Telecanus onocrotalusj and other large birds are in evidence. In May 1983, at the same place, the lower elevations on 68, brief visits in 1970 and 1971, and a six-weeks' visit in the floodplain were covered by permanent open water, and May-July 1983. The primary purpose of the 1983 visit was the higher elevations were perhaps permanently dry. The to compare conditions at that time with those prevailing very productive vegetation that had depended on annual before th,e dams were built. In 1983, various parts of the flooding had been largely replaced by aquatic plants in the Flats were observed from the air and ground, and small open water, while the dry former floodplain had a sparse mammals were trapped in Lochinvar and Kafue National 49 Environmental Conservation, Vol. 12, No. 1, Spring 1985 - © 1985 The Foundation for Environmental Conservation-Printed in Switzerland. Downloaded from https:/www.cambridge.org/core. University of Basel Library, on 11 Jul 2017 at 12:46:23, subject to the Cambridge Core terms of use, available at https:/www.cambridge.org/core/terms. https://doi.org/10.1017/S0376892900015150 50 Environmental Conservation FIG. 2. The same site as Fig. 1 but in May 1983. The permanent Chunga Lake is now part of the reservoir of the Gorge Dam. Its water-level fluctuates somewhat with the flooding ofKafue River, and at high-flood a month earlier the exposed mud-bars were under water. There are few Lechwe and birds, and no emergent vegetation was seen. Parks (Fig. 3). Much information on the effects of the dams flows across the broad Kafue Flats, which ends abruptly at was obtained from interviews with local scientists familiar a range of hills through which the river plunges in a deep with the Rats—especially Professors G. W. Howard and gorge. A short distance below this gorge the Kafue enters Wayne L. Handlos. the Zambezi. The Flats is a floodplain of about 6,000 km2,235 km long and up to 40 km wide (Fig. 3). The River meanders through THE KAFUE BASIN it at a very low gradient for a length of about 410 km. The The Kafue River is one of the main tributaries of the life of the Flats is dominated by the alternating wet and dry Zambezi, arising on the Zaire border and flowing south- seasons, and by the annual floods (W. L. Handlos, 1982). wards to Itezhitezhi Lake. There it turns eastwards and The long-term mean rainfall at peripheral stations ranges FIG. 3. Map of the Kafue Flats (modified from Howard & Williams, 1982). Inset maplet above on right shows position in Africa. Downloaded from https:/www.cambridge.org/core. University of Basel Library, on 11 Jul 2017 at 12:46:23, subject to the Cambridge Core terms of use, available at https:/www.cambridge.org/core/terms. https://doi.org/10.1017/S0376892900015150 Sheppe: Effects of Human Activities on Zambia's Kafue Flats Ecosystems 51 from 77 cm to 90 cm annually, with the rains usually flooding, while many of the birds were migratory, spending beginning in November and ending in April. only part of the year in Zambia. Parts of the Flats are shallowly flooded early in the The situation was further complicated by marked year- rains—from local rainfall and runoff, though the major to-year variation caused largely by differences in the flooding is from the River, by water from the wetter, nor- amount and timing of rainfall and flooding. Both plant thern part of the basin. Before the dams were built the growth and the relative importance of different plants River level began to rise slowly in December and reached varied greatly from year to year, so that different workers its crest after the end of the rains—typically in May, when described the vegetation quite differently. Because of this most of the floodplain was under several metres of water. variation from place to place and time to time under natu- The level then dropped slowly until the next flood began. ral conditions, it is difficult to draw precise conclusions At low water, most of the floodplain was dry, with perma- about the effects of subsequent environmental modifica- nent water only in the River channel and in various oxbows tions by people. and lagoons. Because of this flood regime, the Flats was alternately a PREVIOUS STUDIES OF THE FLATS large lake and a dry grassland. The floods excluded almost all trees, and the vegetation was largely of grasses—most The Kafue Flats ecosystems have been extensively stu- notably Echinochloa stagnina, Oryza longistaminata, and died both before and after construction of the dams. In the Phragmites mauritianus. The grasses usually grew rapidly 1960s, an FAO team produced a multivolume report on the enough to remain above the slowly rising water-level. resources of the area (FAO, 1968). The all-important Because of the abundant water, the floodplain vegetation hydrology of the Flats was studied by the FAO team and was the most productive in the region, supporting large more recently by a Dutch team (DHV Consulting Engi- populations of a variety of animals. neers, 1980). Soils and agriculture were studied by FAO. Lechwe were the most abundant ungulates using the FAO (1968), Douthwaite & Lavieren (1977), and others, floodplain, with smaller numbers of Zebra, Wildebeest, have described the vegetation. The fish and fisheries have and other species in.some places. Hippopotamus (Hippo- been studied by Chapman et al. (1971), Lagler et al. (1971), potamus amphibius) and Crocodiles (Crocodylus niloticus) Dudley & Scully (1980), and Muyanga & Chipundu (1982), lived in and around the water, and there were Sitatunga among others. Several workers have studied bird popula- (Tragelaphus spekei) in dense vegetation. There were also tions (Osborne, 1973; Douthwaite, 1974a, 19746, 1982). several kinds of carnivores and small mammals, notably There have been numerous studies of Lechwe, including the Multimammate Mouse {Praomys natalensis). Most those by Robinette & Child (1964), Bell et al. (1973), Sayer animals moved off the floodplain as the floods rose, and & Lavieren (1975), D. M. Handlos et al. (1976), Schuster later followed the receding flood back onto the floodplain (1976), Rees (1978a, 19786), and Howard & Jeffery (1981, (Sheppe & Osborne, 1971). 1983). Other mammals have received less attention Lechwe are floodplain animals, and a major reason for (Sheppe & Osborne, 1971; Sheppe, 1972, 1973). their success is that they are the only ungulate on the Flats The University of Zambia has had an active interest in that feed in the shallow floodwaters, using the flooded the area since the 1960s, and its Kafue Basin Research grasses while they are still most nutritious (Rees, 1978a). Project (KBRP) continues to study some aspects of the The slowly-receding flood makes fresh food available to ecology and human use of the Flats—including an annual them and other species during much of the dry season. aerial census of Lechwe populations. KBRP has also spon- Over 400 species of birds are known from the Rats, sored several conferences and publications on the area including about 125 waterbirds (Douthwaite, 1982) invol- (Williams & Howard, 1977; Howard & Williams, 1982). ving a large variety of ducks, geese, herons, egrets, shore- In spite of all these studies, two facts stand out. First, our birds, pelicans, storks, ibises, and cranes. The Flats had the understanding of the basin is still inadequate for satisfac- world's largest population of Wattled Cranes (Grus carun- tory protection and management of its resources and, culatus), while Fish Eagles (Haliaeetus vocifer); Darters second, what we do know has had little effect on policy (Anhinga rufa), and Jacanas (Actophilornis africanus), were decisions. The construction of the power project was common. approved without regard to its probable environmental The Flats supported a large fishery, based primarily on effects, and its design and operation have been based the productivity of the floodplain. During the floods the almost entirely on a desire to produce the greatest possible fish moved onto the floodplain and apparently most spaw- amount of power—without regard to other interests. ning and growth took place there.

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