JOHANNESBURG – A 14-year study of nearly 1,000 elephants in Kenya shows an alarming death rate among older males — those with large, valuable tusks — and an acceleration in poaching deaths, the group Save The Elephants said Thursday.

The study said that in 2000 the region of Samburu had 38 known elephant males over 30 years of age. By 2011 only five of those original 38 were still alive.

Almost half of the known females over 30 years also died during this period, at least half from illegal killings, the study found.

Targeted poaching deaths of Africa’s elephants have accelerated in the last several years. The killings are driven by the rising price of ivory as demand increases across Asia — and especially in China.

Animal experts worry that unless China’s increasingly wealthy middle class can be educated about how elephants must be killed in order to provide the ivory used to make small, coveted trinkets, the world’s elephant population will be in danger of being hunted to extinction.

The study, published Wednesday in PLOS One, a peer-reviewed online scientific journal, found that the elephants of Samburu appeared to recognize the threat they faced and increased their reproductive rate.

Africa’s elephants last faced a threat to their survival in the 1970s and 1980s.

But the banning of ivory helped stem the threat until recent years, when the price again began climbing, increasing the incentive for poachers, corrupt government agents and even militant groups to kill elephants for their ivory.