Nature Conservancy Magazine: Winter 2008

Go Deeper

Can Cities and Biodiversity Coexist?
What does this staggering urban growth mean for nature and people?

Read the Full Report
Find out all the details of this groundbreaking study published in Biological Conservation.

It’s official: We’re an urban species. Sometime in May 2007, the balance tipped, and for the first time in history there were more people living in cities than in rural areas. By 2030, cities are expected to account for about 2 billion more people.

Nature Conservancy scientist Rob McDonald, writing in the journal Biological Conservation, found that urbanization is already the main cause of 8 percent of the world’s endangered-species listings. He projects that by 2030, swelling cities will begin to encroach on the borders of an estimated 112 protected areas worldwide. We asked McDonald if there’s a crisis brewing and how to avoid it.

Asia draws a lot of attention in the study — your map of threatened parks is filled with dots in that region. Why?
Think of India and China and their tremendous growth. The average distance between a protected area and a city in East Asia will fall from 43 kilometers [27 miles] to 23 kilometers [14 miles] by 2030. South America and West Africa are other hot spots. There are individual species like the Wimmer’s shrew on the outskirts of Abidjan, Cote D’Ivoire. It exists nowhere else in the world, and it’s unlikely to survive any major urban expansion.

Is there a potential conservation benefit to more people moving to cities?
People tend to use less energy in urban areas, and the U.S. conservation movement did, after all, grow out of cities. It could be good. It’s certainly an important economic process, in that people are moving into cities and out of poverty. But often when people move up the income ladder, they use more energy. What’s really unknown is how conservation movements will play out in other countries. Was the conservation movement here in the States something that was culturally specific? That’s something we talk about a lot at the Conservancy. The other thing you have a challenge with, as people become more urban and less connected with nature, is how to keep them interested in it — especially with all the distractions of the 21st century.

Is it possible for wild areas to coexist with a nearby city?
The Potomac Gorge has 15 globally important species just 10 miles from downtown Washington, D.C. It’s possible, but it can get expensive and difficult to manage. Land prices to expand the park go up, and if you want to do things like controlled burns, you run into problems with houses around. These are some of the challenges that we’ll be facing around the world and the sort of management issues I’ll be looking at in future research.

You suggest concentrating protection efforts in a few key areas that are likely to be most pressured by cities.
The thing that we learned from the study is that these urbanization problems are globally significant but very localized. And because we can draw on a map exactly where threats are, we can plan accordingly.

—Oakley Brooks