Biology Reference
In-Depth Information
Timbavati, zebra and wildebeest were uncommon. Now the animal populations in these areas
are thriving because of provision of water in one of the driest areas and the grass is cropped
short by rhinos as described by Owen - Smith with also the then influx of zebra and
wildebeest. With that has also come the lions and indeed one lion pride has some 30 members.
Owen-Smith has also shown that based on research in the Kruger Park, lions kill wildebeest
and zebra during the wet season when food is more plentiful and to a lesser extent, weakened
buffalo during the dry winter season. Other animals preyed on are dependent on availability,
mostly in a limited area within range of water. He also showed the 25% contraction of sable
antelope range in the Kruger Park was not related to the increase in zebras. However, there has
been research suggesting the decline was due to the increasing use of bore holes and dams to
provide water for zebras, wildebeest and other animals. This brought lions following in tow
and they began increasingly attacking sable that had been long time inhabitants of the more
parched lion-free areas. Indeed, there is now a big move in the Kruger Park of break down
dam walls and close water holes to return these areas to a more natural environment. The
problem with letting nature takes its course is that Mother Nature is cruel. People are not
happy with Mother Nature taking control and allowing the increasing overgrowth of woodland
vegetation on the Lebombo plains and want to bush to be removed to increase grazing for
plains animals. They do not agree to limiting animals like elephants that may be part of the
problem in the decline of plains animals. The increasing woody vegetation, for reasons such as
overgrazing or poor fire management, results in a lower water table and less water being
available for animals, apart from grazing issue. For example, the area along the Southern side
of the Sabi River in the Kruger Park, or the area from Malelane to Skukuza, was open plains of
grass when I was a child but now is increasingly dense woodland acacia vegetation. Where
large herds of zebra, wildebeest and buffalo once existed, the plains animals have become
considerably reduced. Hence also, in Wankie (Hwange) Game Reserve, where there are no
natural water sources and bore hole water was pumped to the surface by diesel pumps, with
the shortage of diesel and un-replaced broken pumps, pumped water is not available for
elephants. The consequence has been that some 86 elephants have died from drought. During
the drought of 1991-1993 in the Gonarezhou, Keith Leggett found that about 1500 elephants, a
third of the population, died, including calves less than 8 years of age. One of the other large
die offs that has been documented was in the Tsavo Game Reserve in the early 1970s and also
occurred because of drought. Apart from man, elephants have no predators and drought seems
to be one factor that has controlled populations.
Thus, with the closure of man-made water sources that have boosted populations, it can be
expected that elephant populations will decline. Since culling is a problem, hunting shunned,
translocation has slowed, and various contraception efforts, including zona pellucida (pZP)
vaccinations have created their own social structure problems (males in musth continually
harass females that are not pregnant, often separating them from their calves, the vaccinations
cost in Makalali R1, 170 and three are needed and needs to be repeated yearly, and there are
other side effects like abscesses).
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