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Restoring nature beyond forests: A new map for rethinking ecological conservation

An international study led by the University of Liège proposes a new map of the potential for natural vegetation on Earth, far beyond forests. By incorporating the role of fire and herbivores, researchers are paving the way for a more realistic and inclusive approach to ecosystem restoration. The study is in Nature Communications.

Is it necessary to plant trees to restore nature? "Not necessarily," says Professor Jean-François Bastin (University of Liège).

The new study led by ULiège proposes a unique map of Earth's potential natural vegetation. Taking into account climate, fire regimes and the presence of herbivores, this study demonstrates that nature is not limited to forests and that restoring ecosystems requires opening up to a diversity of landscapes.

Traditionally, nature restoration has been equated with reforestation. This binary approach—forests or nothing—overlooks the richness of open ecosystems such as savannas, grasslands, scrublands and semi-desert areas.

"We want to move beyond the 'for or against reforestation' debate by showing that other natural states are possible and just as legitimate," explains Bastin.

Using a predictive model fed by more than 40,000 ecological surveys in protected areas and six large climate datasets, the researchers estimated the types of vegetation that each region of the planet could naturally support. And the results are striking:

• 43% of land could be naturally forested,
• 39% could support low vegetation (herbaceous or shrubby),
• 18% would be dominated by bare soil (excluding ice and urban areas).

What's more, the study identifies around 675 million hectares where several vegetation states are possible depending on how fire or herbivory are managed. These landscapes could therefore shift, under equivalent management, between forests and savannas, or between scrubland and grasslands.

Fire, herbivores and human choices: the real drivers of nature

The model developed by the Gembloux Agro-Bio Tech team introduces two factors that are often overlooked in ecological planning: vegetation fires and large wild herbivores. "Our study shows that managing these factors sometimes has a greater impact on the landscape than climate change itself by 2050."

This is a revolution in the way we think about restoration. Where we used to see fixed states dictated by the climate, this research reminds us that landscapes are also the result of natural dynamics and human choices. Ignoring this means risking failure. On the contrary, recognizing that several restoration trajectories are possible opens up a richer dialogue between scientists, managers, decision-makers and local communities.

A tool for decision-makers

Far from remaining theoretical, the model developed can be consulted online (via EarthMap and Google Earth Engine) and allows users to visualize the expected effects of different management policies (frequency of fires, reintroduction of herbivores, etc.) on the potential natural vegetation in a given region.

The maps produced as part of this work are accessible to all: NGOs, government agencies and international organizations. By simulating different scenarios, each stakeholder can better anticipate the consequences of their decisions.

It is a valuable decision-making tool that makes the complexity of ecosystems tangible while promoting strategies tailored to the local ecological and social context.