DNA testing on tons of ivory seized from traffickers has identified two elephant poaching ‘hotspots’ in Africa in a development scientists hope will spur a crackdown on the illegal trade decimating the population of earth’s largest land animal.

Scientists said genetic tests on 28 large ivory seizures, each more than half a ton, pinpointed the geographic origin of the tusks from the two types of African elephant, the savanna elephant and the somewhat smaller forest elephant.

Using dung, hair and tissue samples from elephants across the continent, the scientists devised a map showing where various populations lived based on DNA traits. They extracted DNA from seized ivory and identified the location where elephants with matching DNA live.

Most seized savanna elephant tusks came from a region spanning parts of southeastern Tanzania and northern Mozambique. Most forest elephant tusks came from a region covering parts of northeastern Gabon, northwestern Republic of Congo and southwestern Central African Republic.

A worldwide ivory trade ban was approved in 1989 after Africa’s elephant population plunged from 1.2 million to 600,000 that decade.