The great apes of Africa are faced with near-extinction due to their rapidly diminishing habitat space, according to a scientific survey published in the Diversity and Distributions journal.

The study reveals that in the past 20 years, the Eastern gorilla, the largest living primate, has lost more than half of its suitable habitat. Other great apes, including gorillas, chimps and bonobos, are also being squeezed out by the expanding human population, forest clearance, logging and hunting.

Cross-river gorillas have witnessed the disappearance of almost 60 percent of their habitat over just the past two decades.

"African ape populations are under enormous pressure and in decline," said Hjalmar Kuehl, of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, who participated in the survey, according to BBC.

“The situation is very dramatic; many of the ape populations we still find today will disappear in the near future. ... We knew that pressure on great apes is increasing enormously. But despite these expectations, it is outrageous to see how our closest living relatives and their habitats are disappearing.”

The greatest loss of habitat occurred in the center and east of the Democratic Republic of the Congo, western Equatorial Africa and the upper Guinean forest in Liberia, according to Nature.com

"In an increasingly crowding world with demand for space, wood, mineral resources and meat, apes will continue to disappear," Kuehl further warned. "Without a fundamental change in perception of how precious apes and their habitats are, the current situation will not improve."

Ever-increasing contact with humans present some grave and unique danger to the apes.

The Wildlife Conservation Society lamented that as the number of researchers, eco-tourists, local people and soldiers increase in and around the lowland forests of central Africa, “the likelihood of viruses, parasites and other pathogens passing between them and great apes rises. Research suggests that tens of thousands of great apes have already perished from Ebola hemorrhagic fever virus, which is also deadly to humans.”

The Congo Basin is of particularly important since it is the home of an estimated 100,000 western lowland gorillas and more than 80 percent of Earth’s wild chimpanzees.

“All wild western lowland gorillas live in the Congo Basin, where hunting, farming, ecotourism, political conflict, research and conservation-related activities bring great apes and humans into closer contact,” WCS warned.

“Emerging infectious diseases, such as Ebola and anthrax, are endemic to these dense forests and have proven deadly to both humans and great apes.”