NAIROBI, Kenya—The killing of a lion named Cecil in Zimbabwe has sparked world-wide outrage, but the largest threat to Africa’s big cats is a human population boom that is shrinking the animal’s habitat and posing worrying questions about its future in the wild.
The wild African lion population has declined 42 percent over 21 years, according to the International Union for Conservation of Nature, to fewer than 20,000 lions. The African lion isn’t at immediate risk of disappearing, but conservationists say that if the trend continues, there may soon be few truly wild lions left on the continent.
Africa’s human population, meanwhile, is the fastest growing in the world. In roughly the same period as the lion decline, the number of Africans has nearly doubled to 1.2 billion people. The population will double again to 2.5 billion by 2050, according to the United Nations. At that point, one out of every four humans will live in Africa.
Much discussion about Africa’s population boom has centered on increasingly crowded cities and migrants risking their lives for better opportunities on other continents. But the population surge is also stressing rural populations, who are subdividing land to fit more families and pushing into new areas previously occupied by lions and other wildlife.
More people has meant more forests being turned into pastures, more locals hunting the lion’s prey for their own meals, and more herders killing lions rather than risk losing cattle.
“There’s some cases where the pressure on African wild cats—because of that population issue—is just going to mean that we’re going to lose them,” said Luke Hunter, president of New York-based wild cat conservation group Panthera.
The quest to save Africa’s lions has therefore become a push to find ways for the animals to coexist increasingly closely with humans. Those efforts include payments to communities to protect big animals in their backyard, improving corrals and techniques to keep lions away from cattle, and sometimes even closely managed hunting.
The efforts face daunting hurdles. West Africa and Central Africa have suffered the loss of 66 percent of their lion population. In West Africa, lions are now confined to less than 1 percent of the 4.5 million square miles of sparsely forested land where they used to roam, according to Panthera.
The lion population in East Africa has fallen nearly 60 percent in the same period.
Efforts are under way in East Africa as well. In Kenya, a national park on the edge of the capital has become so surrounded by people that animals can no longer migrate in or out.
“It has become a fenced-in park,” said James Isiche, the East Africa director of the International Fund for Animal Welfare (IFAW). In 2012, local herders hunted down a group of six lions that strayed into a nearby residential area after the lions killed a number of sheep and cows, said Paul Muya, deputy spokesman for the Kenya Wildlife Service.
In Mozambique, the number of people living inside the country’s gigantic Niassa Reserve grew to around 35,000 in 2012 from about 21,000 in 2001, and those people are increasingly clashing with the park’s lions—catching them in snares or hunting them when they attack livestock, said Alastair Nelson, the country director for New York-based Wildlife Conservation Society. In a strange sense of how out of whack the area has become, the park’s lion population has risen because of a jump in elephant poaching for ivory that has created a multitude of carcasses for the lions to feed on, Mr. Nelson said.
Southern Africa overall has actually seen an 8-percent increase in lions—a fact conservationists attribute to more resources devoted to protecting lions and less human population pressure. Southern Africa’s human population is growing substantially more slowly than that of the rest of the continent.
But some of the increase in the lion population in southern Africa can also be attributed to conservation successes that help the local population live with lions, maybe not comfortably, but at least with less fear.
Zimbabwe—where Cecil was slain—is seen as having a successful lion management program, including regulation of hunting based on permits that are lion-specific. In one community near the Hwange National Park where Cecil lived, the Panthera group trains and pays locals to scare off lions by beating drums and blowing vuvuzelas—the plastic horns more commonly seen and heard at soccer matches—to track the cats and report problem lions via mobile phone, and to strengthen corrals to keep lions from making off with cattle.
In Kenya, the government wildlife service has helped herders install large blinking lights in the areas where their livestock sleep in order to scare off lions. The country also passed a law last year that promises government compensation at market price for any livestock a lion kills.
Across swaths of the continent, there is a push to give locals more control over the land, either through long-lease concessions or by helping them set up conservancies that could bring in tourists.
Mozambique’s government is embracing this to curb the influx of settlers into protected areas and safeguard wildlife populations, including elephants and lions, Mr. Nelson said. It is a move on a governmental level that conservationists say has the potential for long-term impact.
“These two—livestock and wildlife—are not necessarily incompatible. You can have a land use that embraces both,” said Mr. Isiche of IFAW, noting the rise of private conservancies that do just that. “But if they don’t get the balance right, at the end of the day the wildlife pays the price.”