Lion Longevity: Ants, Politics and Social Contexts

American writer, conservationist, ecologist, environmentalist, forester, naturalist, philosopher and scientist Aldo Leopold once said that “harmony with land is like harmony with a friend; you cannot cherish his right hand and chop off his left. That is to say, you cannot love game and hate predators … the land is one organism.”

Although Aldo Leopold lived and worked in the United States from about 1909 (when he started with the U.S. Forest Service) to 1948, his statement may never have been more prescient than in today’s Africa, a world away. New data, gathered through years of observation, is now showing that an innocuous-seeming ant is disrupting a whole ecosystem in East Africa, illustrating the complex web of interactions among ants and lions, along with buffaloes, trees and zebras.

But there’s yet another kind of organic web involving lions that could help them navigate the future rather than harm them. While many of Africa’s remaining lions live within small, fragmented populations at risk of disappearing, researchers have just developed a brand-new framework that integrates ecological and sociopolitical risk factors to better understand the fragility of these populations. And that could aid in the big cats’ conservation.

Ants on trees

It seems almost unbelievable that a tiny, invasive ant could do something so grand as change the tree cover in an East African wildlife area, making it harder for lions, the world’s most iconic predators, to hunt their preferred prey, zebras. But it’s true.

According to a report recently published in the journal Science by a team of researchers at the University of Florida—with the help of fieldwork conducted in Kenya led by Kenyan and University of Wyoming scientists in cooperation with The Nature Conservancy—these tiny invaders are pulling on the ties that bind an African ecosystem together, determining who is eaten and where. The study, which spans research over three decades, comprises a combination of hidden camera traps, collared lions tracked by satellites and statistical modeling.

The disruption begins in the acacia trees in the Ol Pejeta Nature Conservancy, an African wildlife area in central Kenya. The trees are historically protected from leaf-eating animals by a species of ant that nests in the trees’ bulbous thorns. In return for their home, the ants ferociously defend the trees from gigantic plant-eaters, such as elephants, giraffes and other herbivores—an arrangement ecologists call mutualism.

Using published studies from the early 2000s, the researchers began to unravel the complexities of this congenial relationship in East Africa between animals and plants. Much to their surprise, they found that these little ants serve as incredibly strong defenders and were essentially stabilizing the tree cover in their landscapes, making it possible for the acacia trees to persist in a place with so many big, plant-eating mammals.

In the latest study, however, scientists say the arrival of an invasive insect known as the “big-headed ant” (Pheidole megacephala) is setting off a chain of events that has resulted in a shift in predator-prey behavior that may further jeopardize populations of lions, a species already on the brink of endangerment.

The big-headed ants are small but voracious hunters of insects, destroying colonies of the tree-protecting ants but not defending the trees from the larger animals. Having lost their bodyguards, the acacia trees are being obliterated by elephants. Lions, which are ambush predators, rely on tree cover to hide and stalk before pouncing on zebras. Less tree cover means lions are not as successful at ambushing their prey.

The scientists say that these invasive ants showed up about 15 years ago; but because they weren’t aggressive toward big animals, including people, not much notice was taken. Now, it’s evident that they are transforming landscapes in very subtle ways but with devastating effects.

For their part, the lions are trying to make the best of a bad situation. The big cats are turning their attention to buffaloes. However, buffaloes are larger than zebras and hang out in groups, making them much more formidable prey.

The scientists note that they don’t know yet what could result from this profound switch in the lions’ hunting strategy, but they are keenly interested in following up on this story. They’re also engaged in finding solutions to halt the loss of tree cover in these iconic landscapes, because the ants are everywhere, especially in the tropics and subtropics.

You can even find them in your backyard in Florida, say the University of Florida researchers, and people are the ones who are moving them around. Currently, the scientists are working with land managers to investigate interventions—including temporarily using fences to keep large herbivores out—to minimize the impact of ant invaders on tree populations.

The researchers conclude that as science continues to move toward highly advanced technologies, such as AI-powered data collection, their group’s steadfast focus on Kenyan wildlife has involved traditional methods over several decades, showing the staying power of boots-on-the-ground research. This study was born, they say, in driving around in the mud in Land Rovers for 30 years.

Lions on brinks

As the ants are now revealing, lion conservation is needed more than ever. Less than half of the 62 known-remaining, free-ranging wild African lion populations house more than 100 lions. African lions now exist in only 26 countries, and nearly half of these nations have fewer than 250 individuals. Eight countries have only a single wild lion population. Although the total African population is estimated to be between 20,000 and 25,000 individuals, there is concern that these small, fragmented populations in countries with few individuals will disappear.

So, now, researchers—including those from the Endangered Wildlife Trust and the Wildlife Conservation Research Unit at England’s University of Oxford, along with 32 additional coauthors from around the world—have developed a new framework which integrates ecological and sociopolitical risk factors to better understand the fragility of these populations. The analysis could provide a guide for conservationists, investors and policymakers to allocate resources most effectively toward saving Africa’s lions.

This comprehensive analysis is a groundbreaker: it’s the first to look at both ecological and sociopolitical risk factors facing lions at scale. Conservation science is important to guide action, but this research, published in the journal Communications Earth & Environment, highlights the invaluable role that economists, development experts, politicians and others must play to safeguard lions and biodiversity. The research findings clearly demonstrate that, even when they are the same size, lion populations may have significant differences in their vulnerability due to ecological and sociopolitical factors.

For example, both Benin in West Africa and Sudan in North Africa have a single known lion population each, that have approximately the same number of lions. However, Benin’s lone population is part of a much larger transfrontier conservation area shared with two other countries, and Benin is a relatively more stable and prosperous country than Sudan. Sudan’s lone population is also contiguous with a lion population in another country (Ethiopia); however, the country is involved in a civil war with people fleeing in the millions. The war and instability undercut the ability of park rangers and others to help ensure the continuation of Sudan’s lions. So, as this comparison shows, when evaluating investments into protecting lions, both ecological and sociopolitical factors must be considered.

To conduct the study, scientists first identified and mapped wild African lion populations. They then created two general categories of population fragility—ecological and sociopolitical—and identified factors in these two categories that may influence the survival of wild lions. For example, a smaller lion population or higher densities of people and livestock were factors contributing to higher ecological fragility, while higher levels of corruption or lower GDP (gross domestic product) per capita would contribute to greater sociopolitical fragility.

Next, the ecological and sociopolitical factors were combined into a single overall fragility index, and each lion population was compared relative to all others. The fragility score does not suggest which lion populations deserve protection or funding. It does, however, highlight the varying anthropogenic and ecological pressures facing different populations and which populations may require relatively more resources (financial or other) to conserve.

The combination of these two indices provided some interesting comparisons. Some populations may ultimately have similar fragility scores, but they are driven by different threats. Thus, while on the surface, the lone lion populations in Benin and Sudan may appear similar, they likely require different levels of investment and perhaps even different types of intervention for conservation to succeed. Pouring money into conserving Sudan’s lions may be relatively ineffective unless the sociopolitical factors, such as the civil war, are dealt with first. Thus, conservation groups, investors and stakeholders must be aware of these differences when approaching lion conservation and evaluating how much money, time or other investment may be needed to see success.

Notably, of the 26 nations that still have lions, 16 of them rank in the 30 poorest countries in the world. The fact that the countries that eliminated their lions a century or more ago are largely those with relatively less poverty today means that the remaining African lions are vulnerable to the pressures felt by many of the globe’s poorest communities.

It’s estimated that $3 billion may be needed annually to maintain the existing lion populations within protected areas. This research underscores the moral responsibility of wealthier nations to contribute more significantly to lion conservation and helps to identify some of the factors which need to be considered to make that contribution more effective.

Leopold on living

Along with the invasive ants, the rapidly growing pressures on natural resources—particularly in Africa—predict a challenging future for lions. With the added human-induced threats of habitat loss, human-wildlife conflict and prey depletion, lions are increasingly being pushed to the brink.

However, substantial efforts are being made to halt lion loss and regain territory for them. Conservation efforts are having some success, such as expanding lion populations in Gorongosa National Park in Mozambique and in Niokolo-Koba National Park in Senegal.

Environmentalist Aldo Leopold also once said something else, which, I think, is one of the best things ever uttered: “There are some who can live without wild things, and some who cannot.”

I hope that you fall into the latter category.

Here’s to finding your true places and natural habitats,

Candy