Population studies of elephant (loxodonta africana) in Tsavo Ecosystem, Kenya: 1975-1980
Abstract
The population dynamics and mortality patterns
of the elephant in Tsavo ecosystem between 1975 and
1980 ,.-~restudied following the recent drastic
decline in their numbers. The population estimate
of the live elephant population wa s determined using
the systematic aerial sample count method. Based on
tltO aerial counts, it was estimated that by 1980 there
were about 12,000 elephants in Tsavo ecosystem. l'lost
of these elephaLts were observed in the areas south
of Galana riYer in Tsavo East and along and north of l'sav(
river and around Lake Jipe in Tsavo "lest. There
was a marked deficiency of elephant numbers in nor-t.Ler-n
Tsavo East.
The age structure of a sample of the live elephant
population was determined using the photogra~etric
technique. The results show that the present
pOPlllation consists mainly of sub-adult animals \\'hose
age ranges between 1 and 15 years. The popUlation
has a marked deficiency in adult animals especially
in localities where poaching was very rampant. The
occurr~nce of large numbers of sub-adult animals in
the preseat elephant popUlation seem to indicate that
the potential for increase in reproduct:ion is
10'''' since the majority of the animals have not yet
reached the reproductive stage.
The age structure of the elephants that died
between 1975 and 1980 was determined fDDm collected
elephant jaws.. The age str'ucture information
indicate that the juveni Le and sub-adult animals of
age ranges betiwe en 0 and 10 years were most susceptible
to mortalitye In adult animals~ mortality seem to have
been highest in those arri.ma La with age ranges between
25 and 40 and between 45 and 50 yearso Information on
the condition of the eLepha nt; car-caeae.s exam.i ried in _the
field i .c. whether their crania were cut or not
coupled with information from rainfall data analysis
for Tsavo East for the years 1969 to 1979 indicate
that the recent drastic decJ.ine in elephant numbers
was caused mainly by poaching (60%) preceded by
drought. Hortality due to poaching was uniformly
spread over Tsavo East and Tsavo \\7est,but that due
to drought was experienced mainly in Tsavo East.
Using the information on the current population
status, it is predicted that the Tsavo elephant
number-s are not likely to increase substantially above
their present numbers in the near futuro (ten or more
years) due to the population'!.s low reproductive
potent.ial. The probability of furt!-lCI'decline in the
present population numbers seem higher than that of
increasing. Two main factors that are likely to
promote further decline in numbers are poaching and
the continuing loss of the ranges utilized by the
elephants to Iive stiock ranching and human settlement.
TIle loss of the elephant ranges to huraan activities
may adversely affect t.he population dynamics and ecology
of the elephant. It may further promote poaching due
to increase in conflict and contact between the people
and the elephant.
The future management problems envisaged for
the Tsavo elephant will therefore centre mainly on
the land-use policy and the control of poaching. It
is suggested thc,t multiple-land use systems should
be introduced in the areas adjoining the Park in which
l..rildlifeconservation and commercial ranching should
playa prominent role. To minimize the poaching of
the elephant, the present anti-poaching surveillance
around and wiithin the Park should continue and be
strengethened"
Finally it is recommended that the distribution
patterns of elephants (and other game), as well as
human activities around the Tsavo National Park
should continue to be monitored at regular .i nt.er-va Ls
on a long-term basis.
"-
Citation
MSc.Sponsorhip
University of NairobiPublisher
University of Nairobi Faculty of Science