African elephant numbers are likely to drop as the high rate of poaching in parts of the continent remained unchanged last year, a study reveals.

At a conservation meeting in Botswana, a report by the Convention on International Trade in Endangered Species (Cites) said the poaching rates of elephants in areas that are being monitored still exceed the animals’ natural birth rates.

Conservationists say tens of thousands of elephants have been killed in Africa in recent years as demand for ivory in Asia, particularly China, increases.

Past estimates of Africa’s elephant population have ranged from 420,000 to 650,000.

The poaching situation appears to have deteriorated in Central and West Africa, though there are “encouraging signals” in parts of East Africa where overall poaching levels have declined, said John Scanlon, secretary-general of Cites.

The study was presented at an international conference on the threat to elephants that is being held in the tourist town of Kasane in northern Botswana. A similar meeting was held in 2013 in Botswana’s capital, Gaborone.

Botswana is a rare bright spot for conservation with estimates of its elephant population as high as 200,000.

The southern African country’s political and economic stability, small human population and other factors make it an elephant haven, though pressure on habitats and conflict with the human population are increasing concerns.

More than 20,000 elephants are being killed annually despite some progress in anti-poaching efforts and the increasing awareness of governments, said Lamine Sebogo, a representative from the World Wildlife Fund who attended the meeting in Kasane.

“Forest elephants in Central Africa are the victims of most of the poaching and we risk losing this unique species if efforts are not stepped up further, all along the ivory trafficking chain,”he said.