African elephants are being pushed over the tipping point, a new study said, with more being killed by poachers for their ivory than are born each year.

“We are shredding the fabric of elephant society and exterminating populations across the continent,” said the study’s lead author, George Wittemye of Colorado State University. The peer-reviewed report was published this week in the Proceedings of the National Academy of Sciences.

Poaching has killed 7 percent of the continent’s elephant population annually from 2010-2013, but their birth rate is just 5 percent, according to the report. At those rates the animals could be wiped out within 100 years, and conservationists are worried.

“We are talking about the removal of the oldest and biggest elephants,” the BBC quoted Wittemye as saying. “That means the removal of the primary breeding males and removal of family matriarchs and mothers. This leaves behind orphaned juveniles and broken elephant societies.”

In 2011 alone, poachers killed about 1 out of 12 elephants in Africa, the study said. Rapidly growing ivory markets in Asia are driving much of the demand, with one kilogram of ivory now worth thousands of dollars.

Scientists say elephants themselves play a role that is harder to quantify but crucial to Africa's ecosystem.

“Elephants are vital to the web of life in Africa. As a keystone species, they help balance all other species in their ecosystem, opening up forest land to create firebreaks and grasslands, digging to create water access for other animals, and leaving nutrients in their wake. Sometimes called the ‘megagardeners of the forest,’ elephants are essential to the dispersal of seeds that maintain tree diversity,” National Geographic reported.

The 2012 slaughter of hundreds of elephants by poachers with automatic weapons in a Cameroon national park, other mass killings, and a United States ban on commercial ivory trade have drawn attention, but the deaths continue at unsustainable levels, the study said.

Efforts to protect elephants from poaching and other threats have until now been thwarted by a lack of accurate data on elephant populations in Africa. This study shows that elephant populations are stronger in some countries than others, with Botswana – which invests heavily in wildlife protection – experiencing healthy population growth. But in Central Africa, the animals’ numbers are down by more than 60 percent, the report said.

“At higher policy levels there have been a lot of questions and debate about what the numbers actually are, what they indicate, and how we should be interpreting them,” Wittmyer told National Geographic. “In my mind what we’ve locked down here and provided the community … are definitive numbers on which they can act.”

With wire services