Elephants or marula trees? A plant ecologist’s uneasy view from the Kruger Park

I have spent my life studying trees in the Kruger National Park. What I am seeing now troubles me deeply. While the elephant debate grows louder and more emotional, a quieter ecological collapse is unfolding. This is not an argument against elephants. It is a plea for biodiversity conservation before we lose something irreplaceable.

I have watched Kruger’s trees for most of my life. As a professional plant ecologist, I have walked its landscapes, studied its vegetation and photographed its changes over decades. Few things have disturbed me as much as the steady disappearance of mature marula trees.

These are not marginal plants. Marulas are among the most iconic, ecologically valuable trees in the park. They anchor savanna systems, feed birds and mammals, shape animal movement and define the character of large areas of Kruger. And yet, within my lifetime, their numbers have collapsed.

To the casual observer this loss is easy to miss. Kruger still looks vast, green and alive. Elephants are abundant. Tourists are reassured. But ecology is not judged by abundance alone. It is judged by balance, regeneration and long-term sustainability. And that balance is breaking.

A line from Aldo Leopold’s A Sand County Almanac has never felt more relevant to me: “One of the penalties of an ecological education is that one lives alone in a world of wounds.”

Those wounds are often invisible to people who do not work closely with ecosystems. Trees do not die dramatically. They decline quietly. And when they stop regenerating, the damage is already far advanced.

A landscape that no longer renews itself

Historical photographs of central Kruger show magnificent stands of mature marulas with expansive canopies. Today, in many areas, what remains are broken trunks, stripped bark and bare ground. In places like the Crocodile Bridge area, the pattern is unmistakable: elephants have smashed or ring-barked the trees, and exceptionally high numbers of impala and other herbivores have removed every seedling and sapling that tries to establish.

The result is a closed ecological trap. Old trees are dying, and young trees are not replacing them.

From a plant ecological perspective, this is not a debate. It is a diagnosis.

How we got here

As a student in the early 1960s, I was taught that conservation meant “the wise use of resources”. Preservation – freezing nature in time – was understood to be neither realistic nor desirable.

During those years I was actively involved with what is now Wessa. Two major conservation battles dominated our attention in Kruger. One was the successful fight to prevent coking coal mining inside the park. The other was raising funds to build artificial water points.

At the time, I was proud of both achievements.

With hindsight, I now recognise that one of them was a serious ecological mistake.

Artificial water points fundamentally altered Kruger’s ecological dynamics. They removed natural constraints on herbivore movement and population size. They allowed animals to remain year-round in areas that would otherwise have offered seasonal refuge to vegetation.

This is not about blame. It is about learning. Conservation is not static. When evidence changes, management must change too.

The elephant debate – and what it misses

Elephants are extraordinary animals. They are intelligent, social and powerful ecosystem engineers. In open systems, their impact is moderated by movement, drought and spatial complexity.

Kruger, however, is not an open system. It is fenced. Movement is constrained. Predators do not regulate elephant numbers. Humans do.

That makes Kruger a managed system, whether we are comfortable with that idea or not.

The elephant debate has become globally politicised and emotionally charged. I understand why. But from my perspective as a plant ecologist, much of the discussion is disconnected from basic ecological principles.

I see emotional arguments, armchair opinions and political positioning. What I see far less of is serious engagement with plant ecology and long-term biodiversity outcomes.

Elephants are slowly but steadily reducing the number of mature marula trees. At the same time, regeneration has all but collapsed due to intense browsing pressure from impalas, nyalas and other herbivores that find marulas highly palatable at every life stage.

This is not speculation. It is observable, measurable and predictable.

Closed systems demand management

Every farmer understands a simple truth: in closed systems, stocking rates matter. If herbivore numbers exceed what the land can sustain, the most palatable species are eaten first – often to local extinction.

John Acocks demonstrated this clearly in South Africa decades ago. Given choice, herbivores repeatedly select the same species until those species disappear.

Marulas are among the most palatable trees in Kruger. Being a marula in today’s Kruger is, quite simply, extremely hazardous.

If biodiversity conservation is our mandate, then allowing this process to continue unchecked is a failure of that mandate.

The question we keep avoiding

I am often told that this is a false choice. That we do not have to choose between elephants and trees. In principle, that is true.

In practice, choices are already being made.

By allowing elephant and herbivore numbers to remain at current levels in a fenced system, we are choosing elephants over marulas. We are choosing short-term comfort over long-term ecological integrity.

So, I ask the question directly: Do we value elephants more than trees – yes or no?

If the answer is yes, then we should be honest about it and accept the ecological consequences. If the answer is no, then we must be willing to manage populations in a way that protects biodiversity as a whole.

Doing nothing is not neutrality. It is a decision with predictable outcomes.

Custodianship requires courage

Kruger is a national treasure. But it is also a human-bounded system shaped by fences, water points and management decisions. We already intervene. The only question is whether we intervene wisely.

True conservation is not about sentiment. It is about responsibility. It is about acting before losses become irreversible.

Trees take centuries to replace. Once regeneration collapses, recovery is not quick or guaranteed. If we wait until the marulas are gone, no amount of regret will bring them back.

The wounds Leopold wrote about are visible to those who know where to look. I see them every time I walk through Kruger.

The marulas are telling us something. As custodians of this extraordinary landscape, we would do well to listen – and to act – while there is still time. DM

Eugene Moll is a retired plant ecologist, currently with an honorary appointment with the University of the Western Cape’s Department of Biodiversity and Conservation Biology. Previously he was the Foundation Chair in Natural Systems Management at the University of Queensland, Australia, head of the Department of Botany at UCT and director of the Southern African Wildlife College. For the past 14 years he has been the botanical adviser to the Keys to Kruger’s Trees project.