Lions are beloved around the world, but their outlook in Africa is increasingly bleak. Having already lost 80 percent of their historical range, their wild population has shrunk by 42 percent in the past two decades alone. And according to a newly published study, things are getting even worse for these iconic animals.

Lion populations in West and Central Africa are projected to decline by another 50 percent over the next two decades, researchers report in the Proceedings of the National Academy of Sciences, unless a "major conservation effort" can be mustered on their behalf. The big cats are also reportedly dwindling in East Africa, which has long been considered a stronghold for the species. Of all lion populations that historically numbered at least 500 individuals, nearly every one is now in decline.

There is still hope, however. The study, which is based on population trend data for 47 different lion groups across Africa, also found that lion numbers are increasing in four southern countries: Botswana, Namibia, South Africa and Zimbabwe. Those gains aren't enough to offset the problems in West, Central and East Africa, but they may shed light on how humans can help other lions claw back from the brink.

"These findings clearly indicate that the decline of lions can be halted, and indeed reversed as in southern Africa," says lead author Hans Bauer, a lion expert with the University of Oxford's Wildlife Conservation Research Unit (WildCRU), in a statement about the new study. "Unfortunately, lion conservation is not happening at larger scales, leading to a vulnerable status of lions globally. In fact, the declines in many countries are quite severe and have enormous implications."

An estimated 75,000 wild lions still existed in 1980, but thanks to threats from humans — namely habitat loss, poaching, poisoning and loss of prey — they've since dwindled to about 20,000. West and Central Africa have seen the worst declines, but the new study suggests East Africa may be losing its lions, too.

The study suggests there's a 67 percent chance that West and Central African lions will lose half their total population over the next 20 years. It also finds a similar, albeit less severe, trend in East Africa, calculating a 37 percent chance that region's lions will also lose half their population by 2035. Yet the study's authors report that southern African lions are defying this trend, thanks largely to better protection.

lioness with cubsA lioness rests with her cubs at Sabi Sand Game Reserve in South Africa. (Photo: Shutterstock)

While many lions in East Africa still roam freely, their relatives farther south are confined to smaller, fenced reserves that are better funded and more intensively managed. Those reserves help keep people and lions separate, reducing not only poaching of lions, but also overhunting of their natural prey that often forces lions elsewhere to hunt livestock. That can lead to retaliatory killings by local farmers, piling onto other problems and helping fuel the big cats' downward spiral.

Aside from fencing them in, governments can also reverse that downward spiral by increasing funds for law enforcement and boosting patrols to weed out poachers. "We've got the solutions," co-author and Panthera president Luke Hunter tells Scientific American, "but the challenge is bringing them to a massive scale."

While it's encouraging that lions are still thriving in at least a handful of places, the scale at which they're vanishing elsewhere threatens to transform the species from an African icon to a regional novelty. "If management budgets for wild lands cannot keep pace with mounting levels of threat," the study's authors write, "the species may rely increasingly on these southern African areas and may no longer be a flagship species of the once vast natural ecosystems across the rest of the continent."

That would be bad news not just for lions, Hunter points out, but also for their entire ecosystems. "The lion plays a pivotal role as the continent’s top carnivore," he says, "and the free-fall of Africa's lion populations we are seeing today could inexorably change the landscape of Africa's ecosystems."

"If we don't address these declines urgently, and at a massive scale, the intensively managed populations in southern Africa will be a poor substitute for the freely roaming lion populations in the iconic savannas of East Africa," adds co-author Paul Funston, director of Panthera's lion program. "In our view, that's not an option."