Wildlife experts in Malawi will next month start moving up to 500 elephants to a sanctuary that they hope could eventually serve as a reservoir to restore some elephant populations in other parts of Africa where the threatened species has been heavily poached.

The massive relocation, slated for completion next year, will involve darting the elephants from a helicopter, hoisting the slumbering animals by crane and loading them in crates on to trucks for a ride of about 185 miles (300km) to Malawi’s Nkhotakota wildlife reserve.

The relocation by African Parks, a non-profit group based in Johannesburg, comes amid increasing pressure on wildlife across much of Africa and especially on elephants, which have been slaughtered in large numbers to meet growing demand for ivory, mostly in parts of Asia.

“There’s a paradox in Africa where elephants are in steep decline in certain places” but require population management in better-protected areas where their numbers are growing, said Andrew Parker, operations director at African Parks.

In Malawi, Parker said, “surplus elephants” stripping large tracts of vegetation and coming into conflict with communities at two wildlife parks, Majete and Liwonde, will move to Nkhotakota, a park of 700 sq miles (1,800 sq km) with more space and security.

African Parks manages all three reserves. Nkhotakota currently has fewer than 100 elephants; Malawi has up to 1,500 elephants in total. Africa has about 470,000 elephants, down from between 3 million and 5 million in the early 20th century, according to the WWF conservation group.

The elephants in Malawi will be moved in small groups in a first phase in July and August, and again in a similar period next year. The Dutch Postcode Lottery, which supports the charity, is a key funder of the $1.6m (£1m) relocation.