EWB’s Large Herbivore Ecology Program

Throughout much of Africa, there has been immense concern that large herbivore and carnivore populations have been affected by habitat fragmentation, anthropogenic pressures, and possibly climatic conditions and hunting. In 2011, EWB began their herbivore ecology research by collaring buffalo, giraffe and zebra in both the Okavango Delta and Chobe National Park, providing ideal locations from which to base comparative studies, to begin to understand the factors affecting wildlife populations. Now, EWB’s projects are monitoring wildlife throughout Northern Botswana, incorporating Msc, Doctoral and Post-doctoral collaborative students from Universities around the globe. The research projects form the basis of long-term, multi-species wildlife research monitoring programs.

herbivore_giraffe_chobeGiraffe Ecology

Wildlife surveys have shown a declining trend in Botswana’s giraffe population over the past ten years, particularly in the Okavango Delta. Whilst ecological information is available for giraffe populations elsewhere, the giraffe of northern Botswana have, until now, been neglected as a focus for ecological studies. EWB has initiated the first dedicated giraffe ecology study in the country. In collaboration with the Giraffe Conservation Foundation, Kylie Mcqualter, a PhD candidate from the University of New South Wales is conducting a comparative study examining the density and distribution, demography, ecology, behavior and social organization of giraffe populations occupying two vastly different environments, the Chobe National Park, where giraffe numbers appear to be stable and in wildlife concession NG26 in the Okavango Delta.
Meet the researcher on Research Team

Migrations & Habitat Fragmentation

Habitat fragmentation affects large mammals when their movement between patches or areas of suitable habitat is impeded or prevented. Barriers may result from changes in land use or land cover through settlement, cultivation or overgrazing, and possibly the erection of fences. These barriers affect ecological and evolutionary processes, while constraints on the seasonal movements and migrations of species can have major implications on their abundance and thus on other species and ecological processes in the area they inhabit. Remarkably little research has been carried out on animal movements across northern Botswana, and even less on the long-term ecological and economic implications of the effects of disrupting movements and migrations of large mammals.

EWB is presently conducting in depth studies at large spatial and temporal scales, investigating the migration routes of zebra, buffalo and wildebeest, while identifying critical wildlife corridors. These studies will aid in assessing the impacts of current land use polices and practices on the long-term sustainability of northern Botswana’s migratory species.

herbivore_collaring_zebraOkavango Delta Herbivores & Flooding Regimes

While Botswana experiences a 30-year drought cycle, in contrast, the flooding regime in the Delta has steadily increased over the past 12 years from a low to a high flooding cycle, resulting in a dramatic change of grazing habitat during the flooding season. Thus, many of the marginal grassland areas have been converted to floodplains of unpalatable sedges. EWB’s aerial survey trend analysis has shown a decline in grazing herbivores in the Delta, over the last 15 years. The main species that are of concern are the grazers that depend on the green flush of the floodplains: buffalo, red lechwe, tsessebe, wildebeest and zebra.

To help understand what may be a driving factor in the population declines in the Delta, EWB is supporting researcher Kyle Burger, studying at the University of Witwatersrand who is examining the relationship of grazing herbivores and their environment, the effect of flooding on the vegetation composition, vegetation change on wildlife population trends, and how certain grazing herbivores move in relation to the flooding parameters in the delta. Thus far, the project is monitoring zebra, buffalo, and for the first time in the country, red lechwe, who have already revealed remarkable movements in relation to the changing floods. Meet the researcher on our Research Team

Woodland Species

herbivore_collared_sable

Roan, sable and tsessebe are considered woodland species and presently there is very little information available within northern Botswana for these particular species, other than anecdotal observations. All three species are of conservation concern at the national level because of their estimated low numbers and the various small subpopulations making up the national metapopulation are isolated from one another. Botswana’s roan population is only about 1,500 animals, its sable population estimated at 3,000 and its tsessebe population may be one of the largest yet in Africa – of the same order as Zambia’s at about 10,000 animals, but yet still are found in isolated pockets. Thus far, as part of EWB’s program focusing on Botswana’s Forest Reserves, satellite-monitoring collars have been deployed on sable and roan within the Chobe district, where both species appear to be increasing in numbers. However, further research will be undertaken, as an understanding of what factors cause animal populations to increase, decrease or remain stable is fundamental to the species restoration and conservation, which we believe should be based upon sound studies of the species’ population ecology and habitat requirements.

Artificial Waterhole Monitoring

Artificial waterholes were put in place by the Department of Wildlife and National Parks (DWNP,) in an attempt to ease pressure off the Chobe riverfront of both tourist vehicle use and to provide water for wildlife in other areas of the Park. EWB, working in conjunction with the DWNP, have started a pilot project to monitor the wildlife utilizing the waterholes, during the day and night, and the impacts they may have. Further information will be provided as the project progresses.