Researched by Gareth Patterson
June 30, 2012
DNA analysis has revealed the existence of five previously unknown, female Knysna elephants in the southern Cape, South Africa. This discovery provides cautious optimism for the world’s most southerly elephant population. Thought by many to be doomed to extinction, with fears in recent years that only one Knysna elephant, an elderly female was still surviving, the findings of a population study conducted using faecal DNA has revealed that the Knysna elephants continue to survive, despite formidable odds. The results of the population study, undertaken by conservation geneticist Lori S. Eggert of the University of Missouri-Columbia and Gareth Patterson, Knysna Elephant Project, have just been published in a paper in African Journal of Ecology, OnlineEarly version, 02 June 2007.
The decline of the Knysna elephants occurred over many decades due primarily to ivory hunting. In 1876 several hundred of these elephants were thought to exist, but under heavy pressure of ivory hunters were reduced to 20-30 individuals by 1908. In 1970 the Knysna elephant population was estimated at 11. In 1994 only one Knysna elephant was known to be still surviving, the elderly female.
In 1994, in an experiment to boost numbers three young elephants from the Kruger National Park were introduced into the range of the elderly female. 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% 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.
Lori Eggert’s conservation research focuses on using non-invasive techniques to provide information needed for the effective management of declining species, secretive or dangerous animals in particular. During her work in West Africa she developed a genetic censusing method for forest elephants using DNA extracted from dung samples. Gareth Patterson has undertaken field research into the diet, range and distribution of the Knysna elephants since 2001. Knysna elephants are elusive and extremely difficult to see. To obtain important population data on these endangered animals, Eggert and Patterson teamed up to undertake the non-invasive genetic survey of the Knysna elephants.
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.
‘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. The results also suggest that the surviving Knysna elephants are closely related to the elephants of the Addo Elephant National Park’ says Patterson.
‘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 out breeding are undertaken’ cautions Eggert.
Since the completion of the study, there is evidence that a Knysna calf was born. This and other evidence gathered in the field by Gareth Patterson, indicates that at the very least, one breeding Knysna bull is or has recently been present in this population.
The Knysna elephants are the only unfenced elephant population in South Africa. They range on National Park, provincial, commercial and privately owned land. Contrary to popular belief, the Knysna elephants are not confined, or restricted, to the Knysna forest, but also utilise mountain fynbos, successional and plantation areas.
Research & compiled by Gareth Patterson
Photo Credits: Hylton Herd/Wilfred Oraai, SANParks