From ancient mastodons to modern grazers, massive environmental upheavals have come and gone — yet Earth’s large herbivore ecosystems have refused to collapse. What’s their secret?
Key Points at a Glance
- Large herbivore ecosystems have remained stable for 60 million years, despite extinctions.
- Two massive global shifts triggered ecosystem-wide reorganizations.
- Even with species loss, the ecological roles stayed intact — until now.
- Scientists warn we may be heading toward a third tipping point due to human activity.
Sixty million years. That’s how long Earth’s large herbivore ecosystems — think mastodons, ancient deer, and rhinos — have withstood the test of time, weathering everything from continental drift to global cooling. A new study published in Nature Communications reveals a remarkable truth: even as species vanished and new ones emerged, the foundational structure of these animal communities remained strikingly intact.
Led by researchers from the University of Gothenburg, the international team analyzed fossil records of over 3,000 species of large herbivores spanning six continents and 60 million years. What they uncovered was both a celebration of ecological resilience and a dire warning about our current trajectory.
According to lead author Fernando Blanco, the ecosystems these animals belonged to “stayed remarkably stable over long periods of time, even as species came and went.” But that wasn’t always the case. Twice in this deep timespan, the environmental pressure was so intense that it triggered full-scale global reorganization.
The first of these ecological revolutions occurred around 21 million years ago. Shifting tectonic plates sealed off the ancient Tethys Sea and formed a land bridge between Africa and Eurasia. That simple geographic change set off a cascade: elephants, rhinos, pigs, deer — they all began to migrate, mingling and reshaping entire ecosystems across the globe. It wasn’t just a reshuffling; it was a reboot.
The second upheaval arrived 10 million years ago with a new, colder, drier climate. Forests retreated, grasslands surged, and grazers adapted with tougher teeth and more specialized feeding strategies. Meanwhile, forest-adapted herbivores began to vanish. This marked a decline not just in numbers, but in the functional diversity — the range of ecological roles — of these animals.
Still, the underlying architecture of herbivore communities somehow held firm. Species changed, but the positions they played in the ecosystem — like strikers, midfielders, and defenders on a football team — remained constant. Ignacio A. Lazagabaster, co-author and researcher at CENIEH in Spain, summed it up best: “Different species came into play and the communities changed, but they fulfilled similar ecological roles.”
Even through the last 4.5 million years of climatic seesaws, ice ages, and extinction events, large herbivore ecosystems have refused to collapse. But today, the pace of change has accelerated beyond anything seen in natural history. Human-driven biodiversity loss is pushing these systems closer to a breaking point. This time, there may be no easy reorganization.
“There’s a limit,” warns senior author Juan L. Cantalapiedra. “If we keep losing species and ecological roles, we may soon reach a third global tipping point — one that we’re helping to accelerate.”
The message is clear. Nature’s past shows us a blueprint for resilience. But it also shows us the cost of pushing ecosystems too far. We’re not just watching history; we’re writing its next chapter.
Source: University of Gothenburg
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