Environment: Urbanization’s Global Impact on Biodiversity and Natural Resources

According to new research, by 2030, expanding urban areas will fill 350,000 square miles, an area the size of Texas. At present, humans are building the equivalent of a city the size of Vancouver every week.

Today, The Nature Conservancy and Harvard University released a new study examining the effect of staggering urban growth on nature and people that finds if we don’t improve urban planning now, we may lose some animals, plants and natural resources for good.

“As a species we have lived in wild nature for hundreds of thousands of years, and now suddenly most of us live in cities—the ultimate escape from nature,” says Peter Kareiva, chief scientist at The Nature Conservancy and co-author of the report. “If we do not learn to build, expand and design our cities with a respect for nature, we will have no nature left anywhere.”

The study, “The implications of current and future urbanization for global protected areas and biodiversity conservation,” was published in the current issue of Biological Conservation and is the first-ever global analysis of how urbanization will affect rare species, natural resources and protected areas in proximity to cities.

In 2007, the United Nations revealed that at least 50 percent of the world’s population is living in cities. By 2030, that number will jump to 60 percent, with nearly 2 billion new city residents, many migrating from rural areas. According to the report, humans are building the equivalent of a city the size of Vancouver every week. While most of the growth is occurring in developing countries like China, India and Africa, ecologically rich areas such as coasts and islands are also at risk.

Kareiva and the study’s lead author Robert McDonald, applied scientist at The Nature Conservancy, built scenarios of urban growth and examined how, at the current pace of urbanization, natural resources and ecosystems could by 2030 be severely damaged. Their findings include:

• Natural areas most affected by urban growth contain some of the highest concentrations of endemic species in the world — these places tend to be small, but significant. For example the Wimmer’s Shrew, found only in the outskirts of the capitol of Cote D’Ivoire on Africa’s west coast, is unlikely to survive the expansion of Abidjan without some help from conservation.
• 8 percent of vertebrae species have been labeled as “endangered” due to the effects of rapid urban development, and that number may continue to rise with new urban expansion and growth.
• In some regions, the proximity between protected areas and cities will greatly increase. For example, in Eastern Asia the average distance from a city to a protected area will be 14 miles by 2030, as compared to 27 miles in 1995. Such proximity will increase the pressures on natural resources and increase the likelihood of resource extraction and other threats to these protected places.

“While we found the effects of urbanization to be localized, cumulatively, they pose a big threat to biodiversity,” said McDonald. “Our urban footprint covers much of the globe and is coming closer to stomping out many endangered species and posing new risks to protected areas and parks.”

Economic concerns will also emerge with rapid urban growth. For example, accidental or intentionally started fires will increase, costing additional dollars and resources to suppress the flames that threaten homes, businesses and buildings. At Tijuca National Park near Rio de Janeiro, Brazil, there are around 75 wildfires a year, almost all caused by humans and most started at the edge of the park by surrounding residents. Water quality is also becoming a grave concern, as urban areas pose significant threats to the health of freshwater systems. For example, in Donana National Park in Spain, rivers are affected by polluted water coming from Sevilla, located 30 miles upstream.

Fortunately, there is hope for turning back this tide of destruction, say the report’s authors.

Governments, city-planners and conservationists can work together to predict and plan in advance for urbanization’s threats to nature. Having information on cities’ impacts to these endangered species and protected areas enables planners to shape the growth of cities before it’s too late, and to implement more sustainable urban planning.

However, a lack of funding, especially in developing countries, may prevent the implementation of smart-growth plans and expanded public transit systems — paving the way for more vehicles and drivers contributing more greenhouse gases to the atmosphere, a major cause of climate change.

“This is yet another vivid example of why conservation cannot simply be about sequestering nature in parks and reserves,” says Kareiva. “We can set up all the reserves we want, but if we do not take care in where we place our cities, how we grow or cities, and how we live in our cities, we will fail in our mission to protect biodiversity.”

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