Research finds more Knysna elephants than expected
05/01/2007 00:00:00
Research and DNA analysis from earlier this year has revealed the existence of five previously unknown, female elephants in the Knysna Forest 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. 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, shows that a few more still survive. 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.
‘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, shows that a few more still survive. 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.
Related to Addo elephants
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.
Close to extinction
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.
A paper detailing these findings appears in the current online issue of the ‘African Journal of Ecology.’
Related to Addo elephants
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.
Close to extinction
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.
A paper detailing these findings appears in the current online issue of the ‘African Journal of Ecology.’
