The Central Kalahari is characterised by scarce and unpredictable rainfall, and wildlife species, particularly large ungulates historically undertook seasonal movements for forage and water.
Unfortunately, the area has been transformed over time through erection of fences, livestock pressure and increasing human population. These changes have impacted negatively on ungulate migration, and wildebeest have been the most hard-hit because of their high dependence on water.
Management interventions have been made, such as provision of artificial waterholes in the Central Kalahari Game Reserve (CKGR), to minimise the impact of land-use changes. Despite these, the wildebeest population has continued to decline. How long and how far this trend will continue is still a mystery.
The loss of the wildebeest population in the region not only affects species richness of the region, but the ecosystem diversity as a whole. Wildebeest form a significant proportion of the large carnivore population diet in the Kalahari - and carnivores of the Kalahari constitute the main tourist attractions in the region. Therefore, from the point of view of tourism as well as ecosystem integrity, a focused study on wildebeest is much needed. Such a study has never been done before, that investigates the specifics of how the wildebeest population is doing in the region, interrogates the success of the management interventions made, and looks at the viability of the remnant isolated landscapes as independent entities. There is also a need to determine what factors have led to the population crashing so dramatically.
The CKGR sits in the middle of the former wildebeest migration range, and understanding the dynamics of the CKGR population will enhance development of a good management plan for the population and the CKGR, and the findings may be extrapolated out to the other areas.
The purpose of this project is to assess whether the Central Kalahari Game Reserve (CKGR) can maintain viable numbers of blue wildebeest independent of surrounding areas. This study aims at evaluating the CKGR as a viable habitat patch of a mostly transformed Kalahari landscape for the conservation and management of the declining and vulnerable Botswana blue wildebeest population.
• To determine the movement patterns and home ranges of wildebeest in the CKGR and neighbouring wildlife management areas (WMAs)
• To determine factors that regulate the wildebeest population within and around the CKGR
• To determine dietary and habitat selection of the CKGR wildebeest population.
To monitor movement patterns of the wildebeest, one female wildebeest in a herd will be immobilised and a satellite collar deployed on it. At least 15 collars will be deployed across the study area in this way, with focus on the core area i.e., the CKGR. The collars will be programmed to record the positions of the wildebeest every 30 minutes for at least two years (which include two dry seasons and two wet seasons).
To determine the dietary selection, collared wildebeest will be located and grazing animals within the herd or an adjacent herd (within the same habitat, assuming the area may have preferred plants) will be observed with the aid of binoculars. The plant species eaten by the wildebeest will be identified and recorded. Selection for grass species will be determined; preferred and ignored swards will be those areas selected or ignored by the wildebeest while grazing, respectively. The ignored areas will be those that the collared wildebeest passed through without any sign of grazing.
To determine how the wildebeest utilise the CKGR in time and space, the study area will be divided into habitat type, depending on the dominant habitat characteristics. The characteristics will be defined by pans, valleys, vegetation type (and grass or herb layer community), waterholes, fire scares, etc. Movement patterns of the collared wildebeest will be assessed across the categories throughout the year for the entire two-year study period. The movement patterns will be broken down into inter-patch and within-patch activities by analysing GPS locations using a technique that analyses the time spent per unit area to determine relative search effort along the pathway.
It is hoped that the outcomes of the project will be used to produce an article of management recommendations for wildebeest specifically and the CKGR in general.
The study has successfully deployed a total of 11 satellite collars across the CKGR (including Khutse Game Reserve) in the last 12 months. All except two of the collared wildebeest spent most of the dry season around artificial waterholes. This showed the importance of the waterholes in the dry season.
The project experienced high mortality of wildebeest, most of which may be a result of waterholes drying. Of the 11 collaring collared wildebeests in the study, 6 died within the last nine months of the project (55% mortality rate!). Three of the animals died within four months after collaring. Three of the dead wildebeests were confirmed to be killed by lions. Dehydration (and possibly exhaustion) is suspected to have killed the other two and there were no clue for the six wildebeest. The death of 4 out of 6 animals happened directly and or indirectly because the waterhole they depended on dried up.
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