The study found that the surge in poaching for ivory that began approximately a decade ago -- the worst that Africa has experienced since the 1970s and 1980s -- has been the main driver of the decline, while habitat loss poses an increasingly serious, long-term threat to the species.
Based on population estimates from a wide range of sources -- including aerial surveys and elephant dung counts -- the estimates for 2015 are 111,000 lower than in 2006.
The continental total is now thought to be about 415,000 elephants, although there may be an additional 117,000 to 135,000 elephants in areas not systematically surveyed, the researchers said.
"It is shocking but not surprising that poaching has taken such a dramatic toll on this iconic species," said Inger Andersen, Director General at International Union for Conservation of Nature and Natural Resources (IUCN) -- the international union for conservation of nature in Switzerland.
The report showed that eastern Africa -- the region most affected by poaching -- has experienced an almost 50 per cent elephant population reduction.
Since the 1990s, central Africa's forest elephant population has been substantially affected by poaching for ivory.
The Democratic Republic of Congo, which used to hold one of the most significant forest elephant populations in Africa, has now been reduced to tiny remnants of its former size.
Gabon and Congo now hold Africa's most important forest elephant populations but both have been affected by heavy poaching in recent years, as have the forest and Savannah populations of Cameroon.
The Savannah populations of Chad have taken heavy losses and those in the central African Republic have almost completely disappeared.
West Africa's elephant populations are mostly small, fragmented and isolated with 12 populations reported as lost since 2006 in Cote d'Ivoire, Ghana, Guinea Bissau, Sierra Leone, Togo, Guinea and Nigeria.
"These numbers reveal the truly alarming plight of the majestic elephant -- one of the world's most intelligent animals and the largest terrestrial mammal alive today," Andersen added.
Although some sites have recorded declines, elephant numbers have been stable or increasing since 2006 in Uganda, Kenya, and Rwanda, and range expansion has been reported in Kenya.
The elephant population in the trans-frontier "WAP" complex that straddles the border between Benin, Burkina Faso and Niger remains the strong-hold of West Africa's elephant population.
"This report highlights how important it is to regularly monitor, assess and analyse the status of the African elephant," said Holly Dublin, Chair of the IUCN Species Survival Commission's African Elephant Specialist Group (AfESG) who led the preparation of the report.
The Report was launched at the 17th meeting of the Conference of the Parties to CITES, in Johannesburg, South Africa, recently.
