Elephants Elephants - Wildpro - Twycross Zoo

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small family units comprising too many calves of similar ages. It is thought
that some of these calves may have joined unrelated females (Nyakaana et al
2001). Work on mitochondrial DNA on this population showed that animals
in these groups were derived from different maternal lineages, indicating a
disruption of the normal social behaviour. It is also thought that family units
coalesce as a response to poaching (Eltringham 1982). Culling is routinely
carried out in the Kruger National Park, RSA (van Aarde et al 1999) where
analysis has shown that once elephant densities reached a certain level the
population declines naturally. Thus there is some evidence for natural
biological control on populations; also data from elsewhere support the theory
that age of sexual maturity i.e. first breading increases with density of
elephants (Dunham 1988).
MINIMUM VIABLE POPULATION SIZE
Habitat fragmentation, as previously mentioned, is one of the major causes of
the decline in wild populations and a major threat for the future. Attempts
have therefore been made to assess minimal viable population sizes (MVP). A
population and habitat viability analysis (PHVA) was carried out on the
elephants of Sumatra in 1993 (Tilson et al 1994). This suggested that
populations of less than 25 individuals were at high risk of extinction and a
population of 40 – 50 animals in secure habitat would have a high chance of
persistence, with no harvesting (i.e. removal of animals). To sustain
harvesting a population of 100 would be necessary. The time frame for this
analysis was 100 years and it has been suggested that this is too short a time
frame to use for analysis of populations with long generations such as
elephant (Armbruster et al 1999) and that a MVP of over 100 animals would be
more realistic. Analysis on size of reserves in Africa was carried out by
Armbruster and Lande (1993), which indicated that the minimum was 1,000
miles 2 needed to maintain populations for 1,000 years. Using the 100 year time
span Sukumar (1992) arrives at a MVP for elephants in south India at 100 - 200
animals allowing for greater poaching of males. Whitehouse and Graham
(2002) examined elephants populations in the Addo Elephant National Park
(AENP) which had been fenced since 1954 (103 km 2, in size ). They found an
above average adult male mortality due to intra-specific fighting, suggesting
that the park was not sufficiently large to accommodate the social needs of the
male population.
SUSTAINABLE USE OF ELEPHANT POPULATIONS
Ecologically sustainable socioeconomic activities are those that are both
ecologically and socioeconomically sustainable. The southern African
countries, as previously mentioned, argue for a sustainable controlled trade in
elephant products i.e. using elephants at a rate which is within their capacity
for renewal. An example of this is CAMPFIRE (Communal Area Management
Programme for Indigenous Resources) in Zimbabwe (Kock 1996). This
initiative includes hunting for sport and trophies, and capture and live sales of
animals. This is carried out within a communal resource management regime
which guarantees that it is the local communities that benefit from revenue