Lion populations are dropping precipitously throughout Africa, and many parts of the continent – West, Central, and East Africa – will likely lose at least half their lions over the next two decades, according to troubling findings published in Proceedings of the National Academy of Sciences this week. Southern Africa is the only place where they’re actually increasing, and that’s mostly because those lions are living behind fences.
Large carnivores are declining around the planet, and the African lion (Panthera leo) is an especially challenging case because of widespread habitat loss, depleting prey, indiscriminate retaliatory or preemptive killing to protect people and livestock, demand in traditional medicines, and of course, poorly regulated sport hunting. And despite being some of the most relatively well-studied big cats, lion populations remain hard to estimate at the regional scale.
So, Hans Bauer from Oxford University's Wildlife Conservation Research Unit and colleagues compiled reliable, repeated surveys of lion populations beginning in 1990 and spanning 47 of the 67 areas where lions are known to live. Many of these populations boasted more than 500 animals at one point. Estimates of these 47 populations were obtained through a variety of ways: individual identifications, total counts, spoor (or track) counts, radio telemetry, photos and transects, for example. Then the team used statistical analyses to estimate the growth rate of each population.
African lion populations are declining everywhere, the researchers found, except in four southern countries: Botswana, Namibia, South Africa, and Zimbabwe. The species is locally extinct in 12 countries already, and quite possibly four more.
Based on their models, the researchers estimate a 67% likelihood that lions in West and Central Africa will decline by half over two decades, and there’s a 37% chance that East Africa will lose half its lions during that same time frame.
By sharp contrast, no populations experienced a decline in southern Africa, where reintroduced lions live in small, fenced, intensively managed, and funded reserves. Some populations are even increasing. In fact, reserves may soon supersede iconic savanna landscapes as the most successful sites for lion conservation, the team writes. It probably also helps that herbivore populations have been increasing in that area too.
Without lions playing their roles as apex predators, many other parts of Africa will be facing major ecological shifts. Bauer speculates that in the short and medium term, hyenas and leopards can fill most of the void, but lion trends are indicative of a deeper crisis that will eventually also affect species with lower requirements. “The flip side is maybe a good message,” he tells IFLScience. “For the conservation of lions we need to conserve entire ecosystems, with all the biodiversity in it, and if the awareness coming from this paper leads to increased conservation efforts for lions, this is good for biodiversity in general.”
Lions are currently listed as “vulnerable” on the IUCN Red List, though the team is recommending separate assessments based on locale: regionally critically endangered in West Africa, regionally endangered in Central and East Africa, and least concern in southern Africa.