Rewilding means bringing back the species and habitats that have disappeared from a region. Initially, conservationists imagined creating vast nature reserves that could be connected by “wildlife corridors” of forest, so that carnivores such as lynx could be reintroduced and thrive in a landscape that’s been heavily altered by humans.

Rewilding is often thought of as a fantastical vision of the future. One day we might share the landscape with wolves and bears, but in the present day, it seems unlikely. For many people in Europe though, that’s exactly what they’ve been doing for at least the past decade.

But that idea is changing. The current emphasis goes beyond just restoring habitats for reintroduced species and considers ecosystems as a whole, and how they can be helped to recover. Better yet, much of this involves little human effort and could have positive consequences for society and ecosystems.

From agricultural land to forest

The cheapest and most effective way to rewild a landscape is to eliminate or reduce as much as possible the causes that have contributed to degrade it. For the last 12,000 years in Europe, these causes have largely involved agriculture and grazing livestock which have destroyed natural vegetation, especially forests, grasslands and wetlands, and replaced them with cropland and pastures.

But as people have migrated from rural areas to cities, large areas of farmland—especially isolated patches in remote areas—have returned to nature. This has been happening in Europe since the second half of the 20th century.

As crops and pastures are abandoned, shrubland and forests naturally regenerate. Despite 40% of the world’s land being cultivated or grazed permanently by domestic herbivores, there has been a big increase in the area occupied by forests in recent decades, explained mainly by these habitats naturally regenerating as humans have left.

Forests returned at a rate of 2.2m hectares per year between 2010-2015 alone. Spain, for example, has tripled its forest area since 1900—increasing from 8% to 25% of its territory. The country gained 96,000 hectares of forest every year from 2000-2015.