Urban rewilding: fad, fantasy, fantastic?

What is rewilding?

Rewilding is a new and emerging form of planned greenery, designed to restore, protect or upgrade ecosystems. Especially popular in Europe, the intent is to support ecological processes to occur naturally, without human management. Rewilding is a far less regulated approach to urban ecological conservation. Projects tend to avoid prescriptive management of habitats, instead allowing natural processes to restore and maintain high levels of biodiversity. Rewilding can happen in urban or rural locations, with different scales and characteristics between locations. This article focuses on urban rewilding.

Rewilded urban landscapes are protected from development, allowing them to naturally deliver complex ecosystem services. A natural succession of habitats and species can then occur in various settings over time. The main responsibility city councils have with rewilding is designating areas of land for nature to occur at various scales. Projects may be anything from a few square metres to several hectares in size. Many have no fixed end point and therefore require different approaches to monitoring and assessment.

The health of rewilded sites is encouraged, especially by eliminating moving, trimming and the use of pesticides or herbicides. Some sites may benefit from some early servicing work before being left to nature – to ensure adequate drainage, for example. Others may need to be initially seeded with wild plants and shrubs. There are other cases where sites need nothing more than the cessation of human management to return to a more natural ecology.

Parkland with rewilded areas, Cork, Ireland.

Not green infrastructure

Green infrastructure, including street trees, green roofs, vegetated surfaces, and green walls, has global recognition for its many benefits and services. For example, shading from strategically planned street trees can lower surrounding temperatures. Green roofs and walls can naturally cool buildings, substantially lowering demand for air conditioning. Green infrastructure can also provide recreational opportunities for people, better management of storm water runoff and improved urban aesthetics. Other benefits and services include the potential to combat urban heat islands, increase social inclusion, improve sense of place, boost property values and increase physical activity and residents’ wellbeing.

While there can be many benefits from green infrastructure in cities, increasing urban biodiversity is not one of its strongest performance metrics. In part, this is because green infrastructure is often over-regulated and intensely managed. This ensures the technologies perform as intended, while not causing unwanted harm. Constant human interference, landscape and species modification, and the use of chemicals are not necessarily conducive to natural ecologies.

I regard urban rewilding projects as distinct from green infrastructure, while also being complementary to it. While rewilding may not offer direct benefits at the building scale, it instead offers wider benefits to the occupants of all surrounding buildings when they are outside. This is because rewilding projects in cities are often found on municipal land and are theoretically accessible to all. Natural landscapes with mixed plant communities attract biodiversity in myriad ways. I believe that any city which really wants to improve its ecological, social and sustainability performance over time should try to facilitate green infrastructure and urban rewilding projects simultaneously.

L: Rewilded area on the campus of University College Cork. R: Rewilded verges along a pathway in public parkland.

Normalising rewilding

Many European city councils are now allowing existing green spaces to return to nature. Wild areas in public green spaces that are no longer mowed or managed are becoming more common, as are wildflower clusters. Rewilded land might not encompass an entire greenspace, but it could be used with specific sub-areas. The visual distinction between managed and rewilded landscapes is often clear to see morphologically and through the vivid colour palettes associated with rewilded land.

Rewilding projects are not just found on public land. Examples are emerging on university and hospital campuses, in churchyards and around sports stadiums. Planter boxes of various style, materiality and configuration are deployed in some cities to support rewilding at a micro-scale. Developers, communities, statutory agencies, and other stakeholders are joining city councils in delivering rewilding projects.

Public and community acceptance is an important issue and should be handled sensitively. A particular hazard is the perception within some communities that the true purpose of rewilding is to reduce council’s responsibility to maintain public and green spaces. True, city councils might initially be encouraged to pursue rewilding based on cost reduction, especially the substantial and ongoing cost of mowing grass. Over time, it is likely that council, communities, and other user-groups will experience the many other benefits and services provided by rewilded landscapes.

Recent evidence from European cities suggests that plentiful native flowers, trees, and grasses, supporting healthy insect communities, can deliver ecological and social benefits to cities beyond anything offered by rigidly managed urban vegetation. It is likely that cities elsewhere will soon start to take notice and follow. Rewilding may soon become a widely recognised and desired addition to urban greening strategies and targets around the world.

Managed and wild landscaping, subtly mixing with buildings, structures and artworks.