| Environment News Service
Report World's Most Southerly
Elephants Survive Against All Odds
KNYSNA, South Africa, June 5, 2007 (ENS) - DNA
analysis has revealed the existence of five previously unknown,
female Knysna elephants in the Southern Cape region at the tip
of South Africa. Researchers say the discovery is reason for
cautious optimism that the world's most southerly elephant
population may have survived the onslaught of ivory hunters in
the late 19th and early 20th centuries.
Inhabitants of the Knysna Forest, the largest indigenous
forest in South Africa, the Knysna elephants are the only
unfenced elephant population in the country. They range on
national park, provincial, commercial and privately owned land.
"The Knysna elephant study identified that at least five
females exist within the population, and two of the animals
identified appear to be first-order relatives and that several
others may be half-siblings," said Gareth Patterson of the
Knysna Elephant Project.
Until very recently, the Knysna elephants were believed to be
on the very edge of extinction, with only one elderly female
still alive.
But the results of the population study, undertaken by Patterson
and conservation geneticist Dr. Lori Eggert of the University of
Missouri-Columbia, shows that a few more still survive.
A paper detailing their findings appears in the current
online issue of the "African Journal of Ecology."
Patterson has undertaken field research into the diet, range
and distribution of the Knysna elephants since 2001.
Because Knysna elephants are elusive and extremely difficult
to see, Patterson teamed up with Eggert to obtain population
data on these endangered animals,
Eggert's research focuses on using non-invasive techniques to
provide information needed for the effective management of
declining species, particularly secretive or dangerous animals.
During her work in West Africa, she developed a genetic
censusing method for forest elephants using DNA extracted from
dung samples.
Because fibrous vegetation eaten by elephants continuously
scrapes cells from the intestine, dung is a good source of DNA.
Genotyping of DNA from dung samples can determine numbers of
individuals, sexes of individuals, the relatedness between them
and the level of genetic diversity present in the population,
Eggert says.
"The genetic diversity of the Knysna elephants is lower than
that found in most African savannah populations, and being such
a small population this is likely to be a serious problem in the
future unless measures to encourage outbreeding are undertaken,"
warns Eggert.
The results suggest that the surviving Knysna elephants are
closely related to the elephants of the Addo Elephant National
Park, says Patterson.
They are apparently not related to three young elephants from
the Kruger National Park that were introduced into the range of
the elderly female in 1994 in an effort to increase Knysna
elephant numbers.
One of the young elephants died of stress-related
complications soon after release. The remaining two elephants
joined up with the elderly female for only short periods before
choosing to spend 80 percent of their time in mountainous fynbos
habitat beyond the Knysna forest.
In 1999 the two young elephants were recaptured and relocated
to the Shamwari private reserve in the Eastern Cape. The Knysna
elephants were then declared by some to be almost extinct.
In 1876, several hundred of these elephants were thought to
exist, but under heavy pressure of ivory hunters were reduced to
20 to 30 individuals by 1908.
In 1970 the Knysna elephant population was estimated at 11.
In 1994, only one Knysna elephant was known to survive, the
elderly female.
Now there is fresh hope for Knysna elephant survival. Since
the completion of the DNA study, there is evidence that a Knysna
calf was born. This and other evidence gathered in the field by
Patterson, indicates that at least one breeding Knysna bull is
present or has recently been present among the Knysna females.
|