To help restore ecosystems that have been damaged by human activities, land managers are increasingly using a hands-off strategy known as rewilding. One of the most successful rewilding efforts was the recent reintroduction of grey wolves in Yellowstone, where the removal of large predators had destabilized the park’s ecosystem.
However, a new study shows that rewilding a landscape requires more than just the reintroduction of a plant or animal. The experts found that geography and geology must also be taken into account.
Kenneth Rijsdijk is an ecologist at the University of Amsterdam, who is presenting the research at the European Geosciences Union (EGU) General Assembly 2021. He explained that it is the landscape that ultimately decides the outcome of rewilding efforts.
One of the key challenges of rewilding is deciding where to do it, said Rijsdijk, especially given competing land-uses like infrastructure and agriculture.
“Clearly, we cannot, and should not, rewild everywhere. It makes sense to pick out specific areas where rewilding is more likely to succeed, taking into account how landscape features, like ruggedness and soil nutrients, can shape ecosystems.”
The success of rewilding is measured based on biodiversity, such as an increase in the abundance and diversity of plant or bird species. These measurements, however, do not factor in the role of landscape, including the topography, river systems, soil and the underlying geology. Known collectively as geodiversity, these aspects of the landscape provide the physical support needed for life.
“Landscape plays a pivotal role in defining the ecosystem: determining where vegetation grows, herbivores graze, animals seek shelter, and predators hunt,” said Rijsdijk.
“It’s remarkable that, from a conservation standpoint, the landscape itself is significantly undervalued in the success of rewilding projects,” said study co-author Harry Seijmonsbergen.
The researchers developed a new index for rewilding that draws on more than a century of geological and geographical map data to measure landscape quality. They also studied how geodiversity influenced rewilding over time using satellite, aerial, and field data.
The team applied their new approach to sites in northwestern Europe that were previously marked by the Dutch State Forestry Service as candidates for rewilding. The experts found that more varied landscapes show greater conservation potential.
“Conservation biologists have been asking how they can pinpoint sites with the right characteristics for rewilding,” said Rijsdijk. “Our research is the first to start building the required toolkit to measure landscape quality and inform that choice.”
The research was presented at the EGU General Assembly 2021.