Good roads in the right places can be a lifeline by providing crops a shorter, smoother trip to the marketplace, making them less likely to spoil. But building new roads in road-free areas can destroy delicate habitats by encouraging logging, hunting and agricultural expansion.

Governments and developers should aim to improve existing poor quality roads — those already located near farms — while keeping new roads out of areas with large natural habitats, such as forests, according to a new study published this week in PLOS Biology.

The research uses data on biodiversity, climate, transportation and crop yields to draft a color-coded mapping system indicating where new road projects should go to provide the most benefits for food production, while being the least harmful to the environment.

Building new roads in pristine areas “is one of the most damaging activities I can think of,” prompting “a barrage of impacts on wild species and habitats that is difficult to reverse,” says Ben Phalan, a research associate at Oregon State University and one of the study authors. “Improving existing infrastructure could benefit farmers and reduce waste, while protecting road-free areas would benefit the countless species of animals and plants that live in such areas.”

A highway cuts across the Yunnan Province of Southwest China. Source: Jianchu Xu & Biaoyun Huai

To be sure, the researchers — who also include Andrew Balmford, professor of conservation science at the University of Cambridge in the UK and Jianchu Xu, professor at the Kunming Institute of Botany in Kunming, China — recognize the value of good roads, especially now that food security has become a concerning issue in the context of climate change, which can fuel prolonged drought.

“In developing countries, post-harvest losses of food are a big problem, and much of this is because of poor infrastructure,” Phalan says. “Imagine what traveling all day under the hot sun in the back of a truck over an unpaved, potholed road can do to a crate of tomatoes or soft fruits. In West Africa, I have seen piles of oranges left to rot in the orchards where they were produced because it was too difficult and costly to get them to market while they were still fresh.”

The scientists focused their study on the Greater Mekong in Southeast Asia, one of the most biologically significant parts of the Earth, and a region that has lost almost a third of its tropical forests since the 1970s.

A new highway snakes through the mountains of the upper Mekong. Source: Jianchu Xu & Biaoyun Huai

The area includes Vietnam, Laos, Cambodia, Thailand, Myanmar and the Yunnan province of China. It has an estimated 20,000 plant species, 2,000 types of land vertebrates and 850 species of freshwater fish, much of which is not found anywhere else in the world. Also, the region’s massive forests act as “carbon sinks,” absorbing greenhouse gases.

But the approach they used also is applicable and relevant for the United States, the scientists say. Infrastructure is a hot topic in America, and the planning of new roads, railways and pipelines is as important than ever.

“The approach and tools need to be modified according to local, national and regional priorities, but I think could be applicable to other regions, including the United States,” says Xu. “Most infrastructure in the United States was built decades ago, if not a century ago, so there is an imperative to update road networks.”

A new highway in the Tibetan Plateau. Source: Jianchu Xu & Biaoyun Huai

The researchers used computer mapping software to overlay maps showing yield gaps — the difference between current crop yields and what could be produced using improved farming methods.

The results showed “where there is most potential to increase production without expanding cropland into new areas,” Phalan explains. “We combined this information with maps summarizing the importance of remaining habitats to biodiversity… and climate regulation. This was to identify places where the environmental cost of roads would be greatest.”

Then, they plotted proposed roads onto this map to see if they passed through areas with potential to improve food production, as well as areas where the environmental costs of new roads would be high.

“The approach taken in our study provides a sort of initial screening of where it might be most environmentally problematic to build new infrastructure,” Phalan says, adding that it would still be necessary for individual projects to undergo an environmental impact statement to find issues not detected in the preliminary look.

This map shows food production benefits and environmental costs. Proposed roads are superimposed in black. Source: Balmford et al., 2016.

“One might think that agricultural expansion in the United States is a
thing of the past. But, in fact, new land continues to be converted to
crops and pasture,” Phalan says. “The role that infrastructure plays in that expansion is not clear. What is clear is that U.S. policies to promote the production of corn… for use as a biofuel has been partly responsible for the continued expansion of this crop.” Phalan believes that a combination of strategies is necessary to plan roads that keep food supplies going while also protecting nature.

“Government planning policy can help,” he says. “For example, in the United States, large areas are designated ‘roadless’ areas, which helps to keep human impacts in such areas low. Finance is another mechanism. Major lenders, such as the International Finance Corporation, are increasingly requiring developers to commit to environmental standards that protect species and habitats.”

The tools highlighted in this study “help pinpoint the projects we should oppose most loudly, while transparently showing the reasons why, and providing alternatives where environmental costs are lower and development benefits are greater,” Xu says. “Conservationists need to be active voices in infrastructure development. I think these approaches have the potential to change the tone of the conversation.”

Marlene Cimons writes for Nexus Media, a syndicated newswire covering climate, energy, policy, art and culture.