Black lechwe (Kobus leche smithemani) is a semi-aquatic medium sized antelope currently enlisted on the IUCN red list of endangered species and is only endemic to the Bangweulu basin of Zambia. Its population has significantly decreased due to floods that took place during the period 1930-1940 from over 250 000-15 000 leading the Zambian government to gazette all habitats of Black lechwe into state protected areas, and to establish urgent management strategies needed to save the remaining population from extinction. Using retrospective data, our findings show that the population has increased from 15 000 animals in 1954 to 55 632 in 2009. The current population is estimated at 34.77% (55 632/160 000) of the carrying capacity of the Bangweulu basin. Although the Black lechwe is one of the 42 species offered for consumptive utilization by the Zambia Wildlife Authority (ZAWA), only 0.12% and 0.08% of the current stock was offered for safari and resident hunting annually for the period 2005-2009, respectively. Annual quota utilization were estimated at 67% (n=37) and 81% (n=37) for safari and resident hunting, respectively. Hence, overall income obtained from utilization of Black lechwe is very low accounting for only 2.1% of the total revenue earned from wildlife utilization. Although the current population trend is showing a unit increase of 639 animals per year, it is still far below levels ideal for the lucrative utilization. In this study, we demonstrate that adverse ecological changes on wildlife species, can lead to their vulnerability and danger of extinction, and that their recovery to full carrying capacity may demand a considerable amount of time.
Key words: Bangweulu, Black lechwe, conservation, ecosystem, utilization.
Resumen
El lechwe negro (Kobus leche smithemani) es un antílope semi-acuático de tamaño medio que en la actualidad se encuentra en la lista roja de la UICN de especies en peligro de extinción y sólo es endémica de la cuenca del Bangweulu de Zambia. Su población ha disminuido considerablemente, de más de 250 000 a 15 000, debido a las inundaciones que se dieron durante el período 1930-1940, lo que llevó al gobierno de Zambia a declarar todos los hábitats del lechwe negro en áreas protegidas estatales, y a establecer estrategias de administración urgentes necesarias para salvar el resto de la población de la extinción. Utilizando los datos retrospectivos, nuestros resultados muestran que la población ha aumentado de 15 000 animales en 1954 a 55 632 en 2009. La población actual se estima en 34.77% (55 632/160 000) de la capacidad de carga de la cuenca del Bangweulu. Aunque el lechwe Negro es una de las 42 especies que se ofrecen para su utilización consuntiva por la Autoridad de Vida Silvestre de Zambia (ZAWA), sólo el 0.12% y 0.08% de la población actual se ha ofrecido para el safari y la caza residente anual para el período 2005-2009, respectivamente. La utilización de la cuota anual se estima en 67% (n=67) y 81% (n=37) para safari de caza y residente, respectivamente. Por lo tanto, los ingresos totales obtenidos de la utilización del lechwe negro son muy bajos contando sólo el 2.1% de los ingresos totales obtenidos de la utilización de la fauna silvestre. Aunque la tendencia actual de la población está mostrando un incremento unitario de 639 animales por año, está todavía muy por debajo de los niveles ideales para la utilización lucrativa. En este estudio, se demuestra que los cambios ecológicos perjudiciales sobre especies de fauna silvestre, puede conducir a su vulnerabilidad y peligro de extinción, y que la recuperación de su capacidad de carga completa puede exigir una cantidad considerable de tiempo.
The Black lechwe (Kobus leche smithemani) is a semi-aquatic medium sized antelope endemic to Zambia’s ]]>
Kobus leche sub-species found in Zambia together with the Kafue lechwe (Kobus leche kafuensis) endemic to the Kafue flats and red lechwe (Kobus leche leche) in Liuwa National Park (NP) in Western Zambia.
The Kafue and Black ]]>
Historical ]]>
Diceros bicornis), a balance has to be struck between consumptive utilization of a threatened Black lechwe antelope and conserving it to levels which allow a healthy recovery of the population from the danger of extinction. Thus we undertook this study to assess the recovery rate of the Black lechwe after the 1930-40 ]]>
Materials and Methods
Study area: The Bangweulu basin covers an estimated area of 30 000km2 which includes three ]]>
2, Chikuni GMA 2500km2 and Kalaso-Mukoso GMA 1900km2 making it one of the largest wetlands in Southern Africa. Game Management Areas (GMAs) are livestockwildlife interface areas around NPs in which rearing of domestic animals is permitted (Balakrishnan & Ndhlovu 1992). The Bangweulu basin is an important ecosystem designated as Ramsar site 531 (RIS 2008). Black lechwe contribute significantly to the ecological balance of the Bangweulu basin by providing faecal nutrients to the various fish species that spawn in the basin. Annual fish production is ]]>
2 while the permanent flooded area covers about 5 000km2 which influences ]]>
The area comprises several mammals, reptiles, fish and avifauna species. Mammals in the GMA and their population estimates are: African Buffalo (Syncerus caffer) – 161; African Elephant (Loxodonta Africana) – 8; Black Lechwe (K. lechwe ]]>
) – 87 000; Oribi (Ourebia ourebi) – 30; Sitatunga (Tragelaphus spekei) – 75; Tsessebe Tsessebe (Damaliscus lunatus) – 500; Zebra (Equus burchelli) – 45. Bird species in the area include the globally threatened Shoebill stork (Balaeniceps rex), and a large population of Wattled crane (
Grus carunculatus). The area has 86 species of fish of which 33 are of commercial value. In addition the GMA is the only area where the threatened slender-nose crocodile (Crocodylus cataphracus) is found in Zambia.
Data collection and analysis: Retrospective data on the Black ]]>
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Results
Population trend of Black lechwe on the Bangweulu ecosystem:Figure 1 shows the distribution of ]]>
Table 1 shows the population trend of Black lechwe on the Bangweulu swamps from the 1930s-2009. The population was at its lowest between the period of 1954 and 1971, while the increase was observed in 1973 and stabilized until 1996.
The current ]]>
Figure 2a shows the population trend since 1930s while A1 shows the estimated carrying capacity of the Bangweulu basin, and A2 the mean estimate for the study period. The current population was estimated to be 34.77% of the estimated carrying capacity (n=160 000) of the Bangweulu GMA. Taking the population trend from 1954 after the ]]>
figure 2b. This gives an intake rate of 1.15% (639/55 632) of the current population estimate. Similarly, the Prais-Winsten regression model showed an estimate of 639 animals (p<0.000, 95%CI 417.49 -859.42). This unit increase of 639 animals per year gives a forecast of another 38 years for the Black lechwe population to reach half (80 000) of the estimated carrying capacity of the Bangweulu basin, and ]]>
Utilization of black lechwe: During the period 2005-2009, ZAWA offered a total of 527 Kobus leche smithemani for hunting disaggregated as 295 and 232 animals for ]]>
K. lechwe smithemani allocated on quota compared to resident hunting which comprises 47%. The quota utilization percentage by the two market segments is on average 62% (n=37 animals) by safari hunting and 81% (n=37 animals) by resident hunters (Table 2). Records of ]]>
K. leche kafuensis for the same study period (2005-2009) averaged around 106 and 571 animals for safari and resident hunting with quota utilization percentages of 42.0% (n=44 animals) under safari hunting and 98.7% (n=564 animals) under resident hunting. Indicative earnings by ZAWA from the consumptive use of the species are given in table 2. Safari ]]>
Discussion
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Monitoring animal population after adverse ecological changes is important for the purpose of determining the exact reduction on the animal population and the rate of recovery after the change in the ecosystem. This is particularly important in animal species that are naturally endemic to particular ecosystems. When these ecosystems are subjected to adverse ecological changes, vulnerable species inhabiting these places are bound to undergo severe population reductions, which might take a ]]>
As shown in table 2, animal counts in the Bangweulu basin were not obtained at regular intervals because of financial constraints experienced by the Zambian government to carry ]]>
et al. 2010, Huy et al. 2010). It is interesting to note that both models gave the same unit increase of 639 animals per annum.
Based on ecological surveys carried out by ZAWA in the last decade (ZAWA 2010, unpublished), the Bangweulu ecosystem can sustain a population of about 160 000 animals if adequate protection and management were provided. Grimsdell & Bell in 1975 (unpublished reports 1975) estimated that it would take approximately 29 years for the population to gain this carrying ]]>
Based on the aforementioned reasons, cropping of Black lechwe is not foreseeable as a population ]]>
Thus far, there has been no major disease outbreak linked to high mortality in Black lechwe and there has ]]>
figure 1, the distribution of the human population in the GMA covers the lechwe populated areas. The increase in human population in the area poses a danger such that illegal hunting of wildlife might continue for a long time. Previous studies (Thirgood
et al. 1992) have shown that approximately 3 000 Black lechwe are hunted illegally every year although it is likely that this number might be an underestimation. Hence there is an urgent need to improve the patrols of law enforcement officers in the GMA/NP, in order to reduce illegal hunting of Black lechwe. Current efforts based on the ZAWA annual reports in the last decade (ZAWA 2010, unpublished) have been directed at involving local communities in the ownership of wildlife as a way of sensitizing the public and putting joint efforts with the general public and government law enforcement agents in curbing down illegal ]]>
In this study we provide a classical example of how a change in an ecosystem can endanger the survival of vulnerable species as shown in the flooding that took place on the Bangweulu basin in the 1930-1940s which led to the significant ]]>
et al. 1992). As shown in this study, the recovery rate of 639 animals per year over a period of 60 years has been very slow by only increasing the number of animals to a third of the carrying capacity of the Bangweulu ecosystem. Put together, the estimated loss of 3 000 animal due to poaching (Thirgood et ]]>
1992) and the estimated unit increase of 639 animals per annum, the Black lechwe population would increase by 3 639 animals per year. Hence, our findings show that one major catastrophic change in an ecosystem can take a long time to regain the loss incurred for vulnerable species endemic to that ecosystem especially when the situation is exacerbated by negative anthropogenic pressure. It is imperative that disaster management should be an integral part of conservation plans aimed at preventing the loss of species vulnerable to major ecological changes. Thus, from this assessment, ZAWA needs to ]]>
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Acknowledgments
We thank the Zambia Wildlife Authority (ZAWA) for allowing us to carry out the study and providing the data.
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*Correspondencia:Victor M. Siamudaala: Kavango Zambezi Transfrontier Conservation Area Secretariat, Box 1171, Gaborone, Botswana; vsiamudaala@yahoo.co.uk Musso Munyeme: Department of Disease Control, School of Veterinary Medicine, University of Zambia P.O. Box 32379, Lusaka, Zambia; munyeme@yahoo.co.uk ]]>
Wigganson Matandiko: Montana State University, Department of Ecology, Bozeman MT 59717, Montana, United States of America; wmatandiko.1965@gmail.com John B. Muma: Department of Disease Control, School of Veterinary Medicine, University of Zambia P.O. Box 32379, Lusaka, Zambia; jmuma@unza.zm Hetron M. Munang’andu: Norwegian School of Veterinary Medicine, Department of Basic Sciences and Aquatic Medicine, Section of Aquatic Medicine and Nutrition, Box 8146 Dep-0033, Oslo Norway; hetron.munangandu@gmail.com, HetronMweemba.Munang’andu@nvh.no
1. Kavango Zambezi Transfrontier Conservation Area Secretariat, Box 1171, Gaborone, Botswana; vsiamudaala@yahoo.co.uk 2. Department of Disease Control, School of Veterinary Medicine, University of Zambia P.O. Box 32379, Lusaka, Zambia; munyeme@yahoo.co.uk, jmuma@unza.zm 3. Montana State University, Department of Ecology, Bozeman MT 59717, Montana, United States of America; wmatandiko.1965@gmail.com 4. Norwegian School of Veterinary Medicine, Department of Basic Sciences and Aquatic Medicine, Section of Aquatic Medicine and Nutrition, Box 8146 Dep-0033, Oslo Norway; hetron.munangandu@gmail.com, HetronMweemba.Munang’andu@nvh.no
Received 11-VIII-2011. Corrected 03-IV-2012. Accepted 03-V-2012.