Predator Control In The Kruger National Park - History Of Kruger

The beginning - Predator Control.

Stevenson-Hamilton was of the opinion that there were too many carnivores, such
as lions in the two Reserves at the time of their proclamation. The reason for this,
he thought, was that the populations of many of the larger herbivores had been
hunted almost to extinction, whilst little harm had been done to the predators.
As a result the carnivores were considered vermin and a nuisance because they slowed
the growth of the prey populations.... A programme of carnivore control was started
which aimed at severely reducing the numbers of carnivores in the Reserves.
The onslaught on the 'vermin' included not only the larger carnivores but also the small
cats, crocodiles, raptors, snakes and honey badger. Significantly in 1912
Stevenson-Hamilton mentioned that he had put a stop to the use of poison
("...which was very effective against crocodiles") as in some areas the disappearance
of the small cats led to large increases in rodents. The extermination of the small cats,
was therefore, abandoned because it seemed "...desirable to keep the balance
adjusted as far as possible'.

1926 - 1945 Controlling predators - the ongoing debate

At a meeting of the Board in September 1926 it was resolved that no more
lions were to be shot 'for the time being' and that the public was not to be informed
of the decision.

Bounty for Wild dogs?

A different approach was taken to wild dogs who, it was speculated had increased
in number since 1924. The Board hence resolved that special efforts must be made
to destroy wild dogs. Owing to the difficulty of the task, the suggestion that a bounty
of £1 per skin be paid, was accepted. The bounty was to be paid by the magistrates
but, when the Transvaal Provincial Administration was approached for approval of the
scheme, it was turned down.

1946 - 1960 Out with the old...

By the time Stevenson-Hamilton retired in April 1944, predator control was limited
to incidental cases along the boundaries, when there was a conflict between
conservation and agricultural interests.

In with the new...

In 1946, Sandenberg, now warden of the Park advised as follows "my urgent
recommendation is that controlled and properly authorized control of lions should
be authorized, as a start in the Shangoni area. The closest observations will be
kept and the result of such lion control reported from time to time. ...
Cautious and conservative measures [must] be adopted and results observed'.

1961 - 1970: The beginning of the end

Throughout the Era the question of carnivore control was raised regularly.
In 1951 Board member JH Orpen said the situation was "desperate" making reference
to a herd of 75-100 sable that had been reduced to 18, ostensibly by predators.
In response it was recorded that "...Henry Wolhuter is almost in tears."
During November 1959 a new policy regarding carnivore control was laid down by Board.
It was stated that the erratic predator-control policy applied between 1946 and 1954 could
only lead to chaos. Control was however deemed "... healthy and essential in the nature
conservation programme, though application may have to be monitored from time to time.

1971 - 1985 The data for the Era 1971-1985:

During this time they were basically convinced that a fenced area would not be able to
readjust itself without "help" from humans. When the grazer numbers declined
(zebras and wildebeest) they felt they had to kill carnivores to ensure the 'balance'
was maintained.

Decline of wildebeest and zebra populations.

In 1972 Smuts stated that the rainfall had exceeded the long-term mean in only four
of the preceding 12 years (1967, 1969, 1971 and 1972). However the extremely wet
conditions experienced during the summer of 1971/72 (759.2 mm) had a deleterious
effect on both zebra and wildebeest. During these months the tremendous increase
in grass cover favoured the hunting activities of predators and caused wildebeest
and zebra to concentrate on small areas where they were able to keep the grass short.
During normal summers (without excessive grass growth) zebra and wildebeest are
more dispersed and predators less successful in catching both young and adult
animals." Unusually high calf and foal mortalities were registered for wildebeest and
zebra in the summer of 1971/72.

In 1975, in an attempt to stop the sharp decline in the wildebeest and zebra populations,
management strategies were proposed by Joubert et al. involving water provision in
under-utilized areas, and controlled burning to flush new grass growth .
Manipulation of animal populations. It was believed that habitat manipulations could only be achieved over the medium and long-term. Although no formal census figures for the lion and spotted Hyaena populations were available, it was generally accepted that there had been a
considerable increase in both.

It was therefore felt that the only immediate step that could be taken to curb the
declines in the wildebeest and zebra populations, would be the
"... drastic relief of the present high predator pressure, thereby achieving a
higher survival percentage of both young and adult animals".
It was also pointed out that "... if no steps are taken against the predators now,
it is probable that the percentage losses amongst the wildebeest and zebra populations
will increase as the populations decline.

Once the populations have declined to the level where they are no longer easily
preyed upon, the predators will be forced to resort to other sources and could
thereby become a direct threat to rarer animals of which some, such as
waterbuck, have shown a marked increase during the few favourable years.
It could also lead to the total disappearance of the small Tssessebe populations
of the Central District and deliver a sensitive blow to the vulnerable sable
antelope population" (Joubert et al. 1975).

"It was further argued that although buffalo and impala provided an alternative
food source for lions, they were less available to spotted Hyaena's and that the
latter would resort to the young of the rarer antelopes. If the prey populations
were allowed to decline, it would eventually lead to a situation where the predator
populations would also start suffering.

Once declines in these populations had begun, the herbivores would have an
opportunity to recover. Declines in the predator populations could, however,
also have adverse effects on the rarer predator species, such as cheetah.
Another aspect that caused concern was that if certain populations were
allowed to decline to a critical level, they might never be capable of recovering
their former numbers.

The small roan antelope population in the Pretoriuskop area was one such

Although these arguments were largely theoretical, it was felt that they were
based on "... well-known and sound principles".
It was therefore felt that there was no other alternative but to institute
predator-culling operations.

"It would, in any event, entail the least risk for all the animal populations -
including the predators, as they would rapidly be able to regain their
numbers with a sufficient food resource of prey animals" (Joubert et al. 1975).

By the Era 1985 to 1994 , thinking had changed significantly re
predator-control policies.

Healthy ecosystems

The first draft of the revised Master Plan for the management
of the Kruger National Park was approved by the Board in 1986.
This essentially made provision for allowing natural processes
to take their course. Inherent in this philosophy was the
acceptance that natural regulatory mechanisms would be allowed to
dictate ecological trends without interference or intervention as
far as this would be possible within the spatial constraints of the
Kruger Park (Joubert 1986c).

The philosophy of allowing ecosystems to take their course was
underpinned by the principle of cycles. Ecosystems are constantly
in a state of change, the changes assuming the rhythms of cycles
with peaks and troughs. These cycles are essential for the
maintenance of healthy ecosystems. Population cycles, in harmony
with other environmental variables, should be allowed to take their course,
in particular with regard to short- to medium-term rainfall cycles.
In addition these should be unaffected by human (i.e. unnatural)
influences. Where population cycles could not be accommodated within
the confines of the Kruger Park, without impacting negatively on
the other components of the ecosystem, action to simulate the natural
situation was regarded as imperative (Joubert 1986c).

The management of the populations of three species was considered
justified, on the basis of the above principles namely elephant,
buffalo and hippopotamus.

Questions were raised, however, about the extent to which buffalo
conformed to these principles and also whether or not zebra should
be taken into account as well.

By the mid-1970s the culling of all animal populations with the
exception of elephant, buffalo and hippo, ceased. At that time
it was also decided to appoint a research officer to take responsibility
for each of these populations with the aim of advising and guiding
the management of the populations.

For this purpose Dr AJ Hall-Martin had been transferred to the
Kruger Park in 1978 to take responsibility for the elephant
population. The buffalo and hippo populations were the responsibility
of Senior Bio-technician IJ Whyte.

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The above story was obtained from various sources and is not all our work.