Growing Biodiverse Urban Futures

How are our cities using nature-based solutions to confront the challenges posed by a warming climate, the loss of biodiversity and major resource depletion? Over recent years, the quality of life in many cities has declined. Reasons for this decline include air pollution, ever-increasing traffic—mostly private cars—and housing that has become unaffordable. Therefore, we must plan ahead better, including for the further increase in urban populations, so that we will not lose the livability of our cities we currently enjoy.

A healthy city is one that continually creates and improves its physical and social environments and expands the community resources that enable people to mutually support each other in performing all the functions of life and developing to their maximum potential. This approach puts health high on the political and social agenda of urban planning and drives a strong movement for public health at the local level as a key driver of all urban development.

Contact to nature is essential for human existence, urban well-being, and good quality of life. Green spaces in cities—big or small—all contribute to the health and well-being of residents. However, many cities do not offer residents easy and fast access to green spaces within the city. Improving the better distribution of and access to green spaces and extending community  gardens and parks is likely to deliver a large number of benefits, such as an increase of ecosystem services, better water management for enhanced urban flood control, slowing down the biodiversity loss, contributing to food security, restoring damaged ecosystems, just to name a few. Furthermore, additional green space and nature-based solutions help to keep cities cool during heatwaves and improve the urban microclimate.

There are valuable opportunities and benefits of applying the concepts of regreening and rewilding of cities. Regreening and rewilding are now used as impactful strategies to strengthen the resilience of cities. The integration of nature-based solutions has emerged as an important tool in the urban design toolbox, with the aim to slow down the biodiversity decline. Rewilding areas in cities is a powerful concept to bring back butterflies, insects, birds, and wildlife. In contrast to highly managed parks and gardens, these rewilding initiatives are leaving allotted spaces mostly uncultivated and self-regulated.

My research over the last 25 years explores the future of green  cities and includes the formulation of strategies based on how biodiversity can be brought back through regenerative design. Regenerative means that the damage already caused to ecosystems is repaired, and it goes one-step beyond sustainable and restorative concepts.

Urban greening refers to the process of establishing the components of green infrastructure and plants within the built environment. There is growing appreciation that regreening cities offers viable solutions by using and exploiting the properties of natural ecosystems and the benefits they provide.

Rewilding activities are ecological restoration and conservation efforts aimed at restoring and protecting natural processes and wilderness areas through the restoration of an area of land to its natural, uncultivated and self-regulated state. The term is used especially with reference to the reintroduction of native species of wild animals, insects, birds, and flora and fauna that have been driven out or exterminated. Through the plants that grow there on their own, rewilding has significant potential to increase biodiversity, create self-sustainable environments, and mitigate climate change. Passive rewilding aims to reduce human intervention in ecosystems, giving human-cultivated land back to nature and restoring nature.

Natural landscapes in cities have become limited, degraded, and replaced with impermeable hard surfaces, such as roads, paving, and car parks. However, the reversal of this trend is dynamic, complex, and still in its infancy. The concept of biophilia, introduced by Edward O. Wilson in 1984, suggests that humans possess an innate tendency to seek connections with nature and other forms of life. Rewilding initiatives can be focused on smaller areas of existing parks. Early urban rewilding initiatives were the Mauerpark in Berlin-Kreuzberg and the High Line in New York City, a once-abandoned elevated railway that went wild over decades before being adapted into a blossoming public park.

The urban resilience of cities refers to their ability to maintain human and ecosystemic functions simultaneously over the long term, even during a disaster or crisis, and their capacity to deal with sudden change while continuing to develop. Similarly, urban resilience, also called adaptive capacity, refers to a city’s ability to cope with and recover quickly from hardship or crisis.

Every city is unique. Cities differ not only in their size and density and in the distribution of their population and green spaces but also in their climatic and cultural contexts, geography, and in the ways in which they are vulnerable to climate change. When it comes to enhancing urban resilience through applying nature-based solutions and regreening strategies, what works in one city may not work in another.

Today, rewilding areas are included as part of new public parks and gardens. The next step is to upscale citywide climate intervention strategies, such as urban forests, deployed to keep cities cool. However, it is essential that the design of the nature-based strategies is fully integrated with other complementary planning interventions and seeks synergies across all sectors.

Main image: Parco Romana by CRA-Carlo Ratti Associati