What Future for the Kafue Lechwe?

Lechwe calf optReview: Shanungu G.K., Kaumba C.H. and Beilfuss R. 2015. Current Population Status and Distribution of Large Herbivores and Floodplain Birds of the Kafue Flats Wetlands, Zambia: Results of the 2015 Wet Season Aerial Survey. Zambia Wildlife Authority, Chilanga, Zambia.

The Kafue Flats make up a 6,500 km2 floodplain along the Kafue river that extends from Itezhitezhi for 400 km downstream to the head of Kafue Gorge. Once considered the most important agricultural entity in Zambia (Bingham 1982) and – with its huge herds of lechwe antelope and vast flocks of waterbirds – offering one of the greatest wildlife spectacles in Africa (Dowsett and de Vos, 1964), its value was severely damaged in the 1970s by construction of hydropower dams that regulate the natural flood.

Despite this change, the Flats remain the only refuge for the Kafue lechwe Kobus leche kafuensis, a distinct race of Red lechwe, and an important area for 12 globally threatened bird species, historically including the largest concentration of Wattled Cranes Bugeranus carunculatus in the World.

Thirteen aerial surveys to monitor the numbers of lechwe were carried out during the 1980s and 1990s. They showed that the lechwe population had fallen from about 94,000 before the floods were regulated to stabilise at around 49,000 in the ‘80s and ‘90s. Fewer counts of cranes were made and census estimates varied more widely, showing no significant change following flood regulation.

Since 2000 only two censuses of lechwe have been made, the last in 2005. The present census report is thus long overdue.

The survey, carried out in April 2015, aimed to map the distribution and census large mammals and birds, including lechwe, cattle and wattled cranes, and record human settlement. The report analyses trends over the past 45 years and discusses factors responsible for change. Recommendations are made to improve wildlife conservation and management.

The survey revealed a dramatic decline in the lechwe population since the census of 2005. Less than 30,000 are estimated to survive, the lowest ever recorded. The survey confirmed a 2005 finding, that the population decline has been greatest on the South bank in and around Lochinvar National Park. By contrast, the population of Wattled Cranes was estimated at 2,962, the highest count in more than 30 years, confirming the importance of this wetland for cranes.

Abundant evidence of human encroachment of the flats was found. Over 92,000 cattle were present in the survey area and cattle posts and fishing villages were observed widely across the landscape, many in the core areas for lechwe, cranes and other waterbirds.

The authors identify a number of possible factors causing the recent decline in lechwe including poaching and excessive hunting quotas, competition with cattle, and disease. However there can be little doubt that the decline in lechwe on the South bank is due to the encroachment of an invasive shrub, Mimosa pigra, that now excludes lechwe from much of its former range within Lochinvar National Park.

A number of management recommendations are made including:

  1. That the boundaries of Lochinvar and Blue Lagoon national parks be extended to create a single park that protects the floodplain between the two from human encroachment;
  2. That habitat restoration to reduce the impacts of invasive shrubs, such as Mimosa pigra and Dicrostachys cinerea, on lechwe, cranes and other wildlife is carried out. Measures should include the introduction of environmental flows from the dams to improve water conditions;
  3. That Park staff should be better equipped for management tasks, and
  4. That aerial surveys should be conducted bi-annually and research and monitoring work on species of conservation concern expanded.

The authors and sponsoring organisations are to be congratulated on presenting an attractive and publicly accessible report that will set the conservation agenda for years to come.

References

Bingham, M.G., 1982. The Livestock Potential of the Kafue Flats. Pp. 95-103. Proceedings of the National Seminar on Environment and Change: the Consequences of Hydroelectric Power Development on the Utilization of the Kafue Flats, Lusaka, April 1978.

Dowsett, R.J. and A. de Vos, 1964. The ecology and numbers of aquatic birds on the Kafue Flats, Zambia. The Wildfowl Trust Sixteenth Annual Report, 1963-1964. Pp. 67-73.

DOWNLOAD THE REPORT:   Shanungu et al., 2015. Current Population Status and Distribution of Large Herbivores and Floodplain Birds of the Kafue Flats

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