A new study challenges the long-held belief that Europe was covered by dense, continuous forests before human intervention. Instead, for more than 20 million years, the continent was a mosaic of open woodlands, grasslands, and wildflower meadows, helped to persist by large grazing animals like elephants and rhinos. The findings, published in Biological Conservation, question current reforestation strategies that prioritize planting dense forests.
The study, led by researchers at Aarhus University in Denmark, analyzed an extensive collection of paleoecological evidence from the Miocene epoch (beginning about 23 million years ago) through the pre-industrial era. By combining fossilized pollen, plant remains, charcoal from ancient wildfires, chemical signatures in herbivore teeth and bones, fossil insects and mammals, and ancient environmental DNA, the team reconstructed Europe's changing vegetation and the role of large animals.
For decades, conservation strategies have been guided by the "closed-forest paradigm", the idea that Europe's natural landscape was a dense, nearly continuous tree canopy before humans cleared land for agriculture. The new research suggests this view is misleading. Instead, Europe's landscapes were typically a shifting mosaic of trees, open spaces, and flowering plants, with varying amounts of tree cover.
Large wild herbivores played a crucial role in maintaining this diversity. Ancient Europe was home to elephants, rhinoceroses, aurochs, and bison, whose grazing, browsing, and ground disturbance helped keep parts of the landscape open and created opportunities for grasses and wildflowers. Many of these animals have disappeared, and traditional grazing practices have also declined, changing how vegetation develops across much of the continent.
"The study shows that current reforestation practices are on the wrong track — both here in Denmark, where subsidies are only granted for planting dense forests, and elsewhere in Europe. This will not only be harmful for biodiversity; it will be in direct contradiction to the type of ecosystems that Europe's species have evolved in over millions of years," said Professor Jens-Christian Svenning, senior author of the study.
The research also reinterprets species often associated with farmland, such as larks, jackdaws, and European hamsters, suggesting their evolutionary histories likely extend back to ancient open woodlands that existed long before modern farming. Wild poppies, now common in fields, also thrived in areas where large grazing animals disturbed vegetation within ancient woodlands.
Lead author Szymon Czyzewski, a PhD student at Aarhus University, noted that "the ecosystems we see in Europe today lack the large wild herbivores that not only shaped landscapes but also sustained its biodiversity for millions of years. The most dramatic shift has largely taken place within the last hundred years, when traditional extensive grazing disappeared from large parts of the landscape."
The findings challenge the sharp distinction between “forest” and “open habitats” often used in conservation planning. The researchers argue that restoration efforts should place greater emphasis on creating and maintaining mosaics of woodland and open habitats, including through the restoration of natural-living large herbivores, rather than simply planting dense forests.
Analysis
Why This Matters
- The study challenges a fundamental assumption behind many European reforestation programs, which often promote dense tree planting for carbon capture and biodiversity. If the continent's species evolved in open, mixed landscapes, dense forests may reduce habitat diversity.
- It highlights the critical role of large herbivores in shaping ecosystems, suggesting that rewilding efforts with animals like bison and horses could be essential for restoring biodiversity.
- The findings have direct implications for conservation policy and subsidies across Europe, from Denmark to EU-level programs, potentially shifting funding toward mosaic landscapes rather than closed-canopy forests.
Background
Europe's ancient landscapes have long been imagined as vast, dark, unbroken forests, a view known as the closed-forest paradigm. This belief has influenced conservation strategies that prioritize letting trees reclaim open areas or planting new forests. The new study, published in Biological Conservation, synthesizes paleoecological evidence from the Miocene to pre-industrial times, using multiple proxy methods to reconstruct vegetation and herbivore influence. It is part of a growing body of research from Aarhus University's Center for Ecological Dynamics in a Novel Biosphere (ECONOVO) that emphasizes the importance of large animals in pre-human ecosystems.
What to Watch
- Whether European governments and the EU revise reforestation subsidy criteria to support open woodland and mosaic habitats rather than dense closed-canopy forests.
- Upcoming rewilding projects that reintroduce large herbivores like bison, horses, and even elephants (in carefully managed settings) to restore ancient grazing dynamics.
- Further research from ECONOVO and other groups that may refine understanding of how different climates and herbivore assemblages shaped Europe's landscapes.
Checked
12 claims in this story checked against 1 source: 12 supported.
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- SupportedThe study challenges the idea that Europe was covered by dense, continuous forests before human intervention.Latest Science News -- ScienceDaily: “Published in Biological Conservation , the findings challenge a longstanding assumption about what Europe's wilderness looked like before widespread human intervention.”
- SupportedThe research spans 23 million years.Latest Science News -- ScienceDaily: “examining paleoecological records from the Miocene epoch (which began around 23 million years ago) through the pre-industrial era.”
- SupportedFor more than 20 million years, Europe's landscapes were typically a mosaic of trees, open spaces and flowering plants.Latest Science News -- ScienceDaily: “Across more than 20 million years, Europe's landscapes were typically a shifting mosaic of trees, open spaces, and flowering plants rather than continuous stretches of closed forest.”
- SupportedLarge grazing animals helped maintain those open landscapes.Latest Science News -- ScienceDaily: “By feeding on vegetation and disturbing the ground as they moved, these animals helped keep parts of the landscape open.”
- SupportedThe study's findings question reforestation programs that often prioritize planting dense forests.Latest Science News -- ScienceDaily: “They also raise important questions about modern reforestation programs, which often prioritize planting dense forests to combat climate change and protect biodiversity.”
- SupportedJens-Christian Svenning said current reforestation practices are on the wrong track in Denmark and elsewhere in Europe.Latest Science News -- ScienceDaily: “The study shows that current reforestation practices are on the wrong track - both here in Denmark, where subsidies are only granted for planting dense forests, and elsewhere in Europe.”
- SupportedThe researchers combined pollen, plant remains, charcoal, chemical signatures in herbivore teeth and bones, fossil insects and mammals, and ancient environmental DNA.Latest Science News -- ScienceDaily: “These included fossilized pollen and larger plant remains, charcoal left by ancient wildfires, and chemical signatures preserved in the teeth and bones of plant-eating animals. The researchers also examined fossil insects and mammals, along with ancient environmental DNA”
- SupportedAncient Europe was home to elephants, rhinoceroses, aurochs and bison.Latest Science News -- ScienceDaily: “Ancient Europe was home to animals such as elephants, rhinoceroses, aurochs, and bison.”
- SupportedSzymon Czyzewski said Europe's ecosystems today lack large wild herbivores that shaped landscapes and sustained biodiversity for millions of years.Latest Science News -- ScienceDaily: “The ecosystems we see in Europe today lack the large wild herbivores that not only shaped landscapes but also sustained its biodiversity for millions of years.”
- SupportedCzyzewski said the most dramatic shift largely took place within the last hundred years, as traditional extensive grazing disappeared from large parts of the landscape.Latest Science News -- ScienceDaily: “The most dramatic shift has largely taken place within the last hundred years, when traditional extensive grazing disappeared from large parts of the landscape.”
- SupportedThe researchers suggest larks, jackdaws and European hamsters likely have evolutionary histories extending back to ancient open woodlands.Latest Science News -- ScienceDaily: “Yet the researchers suggest that their evolutionary histories likely extend back to the open woodland environments that existed long before modern farming.”
- SupportedThe researchers argue restoration should maintain mosaics of woodland and open habitats, including through restoring large herbivores.Latest Science News -- ScienceDaily: “Instead, restoration efforts should place greater emphasis on creating and maintaining mosaics of woodland and open habitats - not least through the restoration of natural-living large herbivores”