Just 30 tree species dominate world's most diverse savanna

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Scientists have found that a mere 30 species of trees in the Cerrado—the world's largest and most floristically diverse savanna—account for nearly half of all its trees.

This phenomenon of "hyperdominance" by a few species has significant implications for understanding and conserving this important ecosystem.

The study, by scientists from Brazil, the U.K., and the Netherlands and published in Communications Biology, draws on data from more than 200 one-hectare field plots combined with satellite imagery and spatial modeling.

The findings show that 30 species—less than 2%—of the Cerrado's 1,605 tree species make up almost half of all the trees.

Among this distinct group of hyperdominant trees, one species, Qualea parviflora, was found to make up one in every 14 trees.

"We were surprised by this level of hyperdominance in such a diverse ecosystem," said lead author Dr. Facundo Alvarez, from the State University of Mato Grosso (UNEMAT).

"This pattern is similar to what's been observed in the Amazon rainforest, although the Cerrado is a savanna. Our research also determined that the Cerrado has lost an estimated 24 billion trees since 1985—a staggering figure equivalent to three times Earth's current human population. Understanding the dominance of these few species is essential in light of such losses."

Spanning 2 million km²—an area the size of England, France, Germany, Italy and Spain combined—the Cerrado is the largest savanna in the world and the most floristically tree-diverse, as well being a gateway to Amazonia and playing a vital role in supplying clean water and sequestering carbon.

This hyperdominance of a few species, now found in both Amazonian forests and the Cerrado, highlights the risks both biomes face for species loss due to fragmentation, deforestation and land-use change.

"When so many ecosystem processes are concentrated in 30 or so individual species, it means that if you disrupt this system, for example, through climate change, then depending on how those species respond to that disruption, there's a risk of losing the species that are key to maintaining the core functionality of the savanna as a savanna," said co-author Professor Ted Feldpausch from the University of Exeter.

As only 30 species dominate the Cerrado, its stability and functioning are very narrowly based. But Professor Feldpausch explains that focusing on these species could help researchers understand how this vast ecosystem functions.

"It could help us make predictions about how the system as a whole is going to function—and potentially how it will respond to disruptions, whether from changing fire regimes or a changing climate," he said.

Lead co-author, Professor Beatriz Marimon, from the University of Mato Grosso State (UNEMAT), added, "It's going to help us with conservation, knowing where we find higher and lower diversity; it's going to help with management—so knowing, for example, whether these are species are more or less adaptive to fire; and if we're trying to restore areas, understanding these few species is going to help with that too."

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The critically endangered Cerrado biome plays a crucial role as the gateway to Amazonia and other biomes but is just 8% protected and more than half deforested.

To date, it has acted as a barrier, helping to separate Amazonia from the densely populated and urbanized southeastern region of Brazil.

The Cerrado plays a crucial role in supplying water to major cities, regulating climate, and acting as a natural barrier between the Amazon and Brazil's heavily populated southeast. "Yet global environmental policies continue to overlook the Cerrado," said co-author Professor Ben Hur Marimon Junior from UNEMAT. "Its protection must become an international priority—not a burden carried solely by local communities."

The researchers warned that up to 800 tree species may remain undetected and face extinction in a few decades due to deforestation.

More information: Facundo Alvarez et al, Tree species hyperdominance and rarity in the South American Cerrado, Communications Biology (2025). DOI: 10.1038/s42003-025-07623-w

Journal information: Communications Biology

Provided by University of Exeter