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Thursday, 26 September, 2002, 11:58 GMT 12:58 UK
W African elephants 'separate' species
African elephants
African elephants have a high conservation profile

DNA evidence suggesting that there are three different species of elephant in Africa could lead to a heated debate among zoologists.

Researchers at the University of California at San Diego (UCSD) say the elephants of West Africa are a separate species from either the savannah elephants of central, eastern and southern Africa and the forest elephant.

Just over a year ago, it was generally accepted that there was one species of elephant with perhaps two sub-species.

Then genetic evidence indicated that the forest elephant was a separate species. It is smaller than the savannah elephant with smaller, straighter tusks.

Forest elephants
Forest elephants are said to be a separate species
Now DNA studies suggest the West African animals are sufficiently different genetically to be classified as a third species of African elephant.

But the DNA evidence is not accepted by all zoologists and mammal specialists as sufficient evidence that there are separate species rather than just sub-species or even just slight variations among a single species.

The existence of three separate species or even three sub-species would have strong implications for conservation strategies for elephants in Africa.

Each of the three groups of elephants have varying numbers, live in different environments and face a range of threats to their existence.

The San Diego researchers say that West African elephants are "genetically and geographically isolated from elephants elsewhere on the continent" and have both savannah and forest forms.

They believe the population in the west has been isolated for 2.4 million years.

Dishing the dirt

The evidence of a new species comes from analysis of DNA from savannah, forest and West African elephants.

"This discovery is important, because West African elephants are threatened with extinction as a result of human activities," says David Woodruff of UCSD's biological sciences department.

"If these findings are confirmed, zoologists and conservation managers will need to recognise three different species of African elephants, all of which need protection because their numbers are declining," he adds.

The DNA evidence was taken from intestinal material found in the dung of the elephants.

Not all mammal experts are convinced by the research, however.

Professor John Skinner of the Pretoria University Memorial Research Institute told BBC News Online that "the jury is still out" on whether the forest and West African elephants are separate species rather than sub-species.

He cautioned against using purely genetic evidence when more work could be done to look at the effects of environment on dispersed elements of the same species.

He said there was some controversy about the issue at the international mammal conference in South Africa in 2001.

Conservation strategies

The World Wide Fund for Nature is concerned with conserving elephant numbers - whether they are one or three species.

The fund estimates that there are between 300,000 and 487,000 elephants left in Africa, but says that estimating populations is difficult and can be imprecise.

Savannah elephant
Savannah elephants are bigger with curved tusks
But the numbers of elephants have declined dramatically in recent decades. Some estimates suggest that the numbers have fallen from 1.3 million in 1981 to 400-500,000 now.

Of these, the majority (about 250-350,000) are savannah elephants, most of the rest are forest elephants and a mere 12,000 are West African elephants.

The main author of the San Diego report, Lori Eggert, says that the differences between the three types of elephants mean that conservationists need to be aware of varying levels of threat.

"Overpopulation in some southern African parks should not lead to a relaxation of the protection for elephants elsewhere, especially in the forests."

Forest elephants, including forest-dwelling West African elephants, "live in a habitat that is rapidly being logged and converted to agriculture.

"Increasingly forests in Africa are becoming fragmented and elephant populations are being isolated in a sea of farms and villages," according to Lori Eggert.

The WWF also believes there have been different levels of loss among the three groups of elephants. They point out that elephant populations in West Africa started to decline much earlier than the other populations.

Threats vary

There are also different causes of decline in different areas. Poaching has been a major problem in eastern Africa, while in the west, this has been combined with the effects of logging and population pressure.

Elephant populations in southern Africa are increasing.

This has led to differences between eastern and southern African countries over whether the ban on the trade in ivory should be lifted.

Southern African countries such as Botswana, South Africa and Zimbabwe have been in favour of at least a partial lifting of the ban, while Kenya and Tanzania have been opposed on the basis that their elephant populations suffered most from poaching and the ivory trade.

Whether the argument for three species prevails, it is clear that the regional variations in the threat to elephant numbers are leading to a renewed debate over the correct strategies for conservation.

See also:

23 Aug 01 | Science/Nature
31 Aug 02 | Science/Nature
14 May 02 | Science/Nature
08 Mar 01 | Science/Nature
13 Sep 00 | Science/Nature
20 Feb 00 | Washington 2000
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