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Nature needs cities, and cities need nature (commentary)

Landsat image of Central Park in New York City. Image courtesy of NASA.

  • At a time when the world is losing its biodiversity at an alarming rate, and that loss has been linked to disease outbreaks, urban nature is more important than ever. Yet urbanization is a major cause of habitat loss – which drives much of the staggering loss of biodiversity
  • With thoughtful planning, cities can connect habitats within and outside of city limits in ways that help protect populations of animals and plants that would otherwise be fragmented and vulnerable to extinction.
  • This article is a commentary. The views expressed are those of the author, not necessarily Mongabay.

Wild boars have descended from the hills and entered Barcelona, and sika deer have been seen strolling deserted metro stations in Japan. While such unusual visitors will retreat as Covid-19 is brought under control, their sudden presence and more subtle changes in urban nature highlight an important dimension for post Covid-19 recovery: the integration of nature in cities to support both human health and biodiversity.

At a time when the world is losing its biodiversity at an alarming rate, and that loss has been linked to disease outbreaks, urban nature is more important than ever. Yet urbanization is a major cause of habitat loss – which drives much of the staggering loss of biodiversity. If we are to conserve biodiversity, we need to do so in cities, too.

Cities have long been typified as barren wasteland. However, studies argue that the opposite can be true: a number of cities across the globe host significant biological diversity. Cape Town, for example, is home to 50 percent of South Africa’s critically endangered vegetation types.

Otters had disappeared from Singapore when, in 1977, the government launched its Clean River Campaign. In 1998, otters began to return to the island. Today, at least 90 otters live in city waterways. Singapore has continued to expand its nature revolution and today is a haven for biodiversity. Close to 10 percent of the total land area is set aside for parks and nature conservation, all connected in an island-wide network of green links.

With thoughtful planning, cities can connect habitats within and outside of city limits in ways that help protect populations of animals and plants that would otherwise be fragmented and vulnerable to extinction.

In addition, a rich body of research documents the benefits of urban nature to human health and well-being.

Landsat image of Adolfo Ducke Forest Reserve in Manaus, Brazil. Image courtesy of NASA.

Research shows a positive association between the percentage of green space in peoples’ living environment and their perceived general health. Some of this is because nature encourages physical activity, which builds a stronger immune system.

Polluted air is responsible for the deaths of 7 million people every year. Long-term exposure to air pollution may also be an important contributor to fatality caused by the current pandemic. A large body of literature suggests trees can provide localized but meaningful improvements in air quality.

Connecting with nature can be good for our mental health, too. Forests have a host of human mental health benefits, including boosting mood, reducing stress, anxiety, and confusion; and improving sleep and creativity.

The United Nations expects that 68 percent of the world’s population will live in urban areas in 2050, up from 55 percent today. The economies of many countries are concentrated in cities. With most of the world’s population and financial power in urban centers, it is imperative that city dwellers have easy access to Nature. This will not only benefit human health and biodiversity, but also deepen urbanites’ appreciation of – and willingness to fund – the conservation of nature.

Earth at Night, the Americas. Courtesy of NASA

Some might argue that integrating nature into cites will bring diseases that can spread from animals to humans. But the very lack of urban biodiversity raises risks of such zoonoses.

Today’s urban environments are typically characterized by reduced species diversity and a higher proportion of those species that more easily adapt to human-dominated spaces. Many of these urban species – including rodents – carry pathogens dangerous to humans. Furthermore, the lack of biodiversity means these common pests have no natural predators to keep their numbers in check. Planning for nature in cities can conserve natural habitats and re-establish predator-prey relationships. For example, in some Brazilian cities and towns where a rodent spreads hantavirus disease to people, barn owls have been found to play an important role in control of the rodent.

Covid-19 has taught us that life on Earth is interconnected. As a dominant species in the web of interaction, people have a huge responsibility to get it right. In cities, this includes expanding natural areas where possible, improving the management of these new and existing areas, and increasing their connectivity.

There is growing momentum to such initiatives. The CitiesWithNature project brings together officials of local and regional governments to incorporate nature into post Covid-19 planning. It highlights the role of green infrastructure and open green spaces as two basic elements of future cities.

Nature needs people’s assistance; people need nature; and cities need nature for long-term viability!

Johan Robinson is Chief of the Global Environment Facility Biodiversity and Land Degradation Unit at UN Environment Programme, where he leads conservation projects in 152 countries. He has more than 25 years of experience working on the interface of Nature and Development.