Roads to ruin: Africa’s massive infrastructure expansions could have major consequences

Countries in sub-Saharan Africa sit at a crossroads. Foreign investments – mostly in the continent’s abundant natural resources – have some economies booming. And yet even in many of the countries extolled as success stories, poverty abounds, people go hungry, and natural resource exploitation leads more often to environmental degradation than to meaningful jobs and tangible skills for African workers.

Meanwhile, donors and lawmakers have seized upon the idea of development corridors – massive, concerted efforts to build up infrastructure designed to kick start the economy and find ways to feed a population set to quadruple this century. “The African continent is going to change profoundly,” said tropical ecologist Bill Laurance.

But what will the influx of people, businesses, and agriculture into these areas mean for the environment in Africa?

To answer that question, Laurance and his colleagues at James Cook University in Cairns, Australia, set out to comprehensively analyze the potential environmental and agricultural impacts of 33 development corridors, as well as determine how many people live within their boundaries. Then, they used these measurements to compare the costs and benefits of each corridor on the continent to figure out quantitatively which ones seem like good ideas and which ones don’t. They published their research today in the journal Current Biology.

The team worked out the potential environmental effects by analyzing maps of each corridor and taking into account a range of measurements, including the number of plant species and threatened animals, as well as how much carbon the area stores.

They also took stock of a region’s agricultural potential based on considerations such as soil quality, climate, and whether the corridor affords the opportunity to improve upon the low yields so pervasive in Africa. And by looking at satellite imagery of lights in Africa at night, they were able to distinguish dense population centers from barely peopled hinterlands.

Once the researchers integrated all of these measurements, they assessed which development corridors were likely to wreak the most environmental havoc.

The authors contend that it makes the most sense to place corridors in areas where humans already live and farm and that aren’t particularly unique or valuable from an environmental perspective. “The point is to try to facilitate more intensification and more yield improvements on already-settled land wherever possible,” Laurance said. “Don’t just rip open many of the last remote areas of Africa.”

But in many spots, that’s exactly what could happen.

“Huge numbers of these corridors are going to crisscross Africa and slice right into areas that have very high environmental values, have very sparse populations, and don’t seem to have a lot of agricultural potential,” Laurance said. In fact, 75 percent of the corridors they looked at are sited in “sparsely populated” areas.

Of the 33 planned and active corridors examined, only six qualified as “promising” in the researchers’ estimation, because they combined promising agriculture possibilities and low conservation priority. Several others don’t seem like good ideas at all: Based on the paper’s analysis, these corridors aren’t agriculturally valuable, but they do encroach on lands important to conservation. The rest fell somewhere in the middle.

Laurance said the variable suitability was puzzling. For example, more than a third of planned corridors are slated for forest areas, which hold huge amounts of biodiversity and carbon-capturing potential but aren’t nearly as good for farming as savanna woodlands. The authors also point out that, on average, the 14 planned development corridors won’t lead to as many agricultural benefits like enhanced yields and access to markets as do the 19 already in existence.

The team analyzed not only the corridors themselves, but also the areas around them. Laurance said it’s one thing if the corridors limited the impact to the narrow strips of development. “But that’s not what happens,” he said. “What happens is you get a whole spider web of secondary and tertiary roads.”

And that’s the intent of the corridors. They’re designed to attract people and companies and agriculture, but the roads and railways at their core also lead to deforestation, fragment important habitats, and allow hunters easier access to their wild quarry. Analysis for a 2014 study that Laurance coauthored found that 95 percent of deforestation in the Brazilian Amazon occurs within 5.5 kilometers of a road.

The consequences can extend far beyond that distance, however. Laurance pointed out that construction of the first paved highway through the Amazon in the 1970s left behind a “400-kilometer-wide swath of forest destruction today.”

Laurance and his team provided a more accurate look at the knock-on impacts of corridors by including a 50-kilometer band that stretched 25 kilometers on either side of the corridor’s main highway or railroad. On their own, the corridors alone cut through 408 protected areas across the continent. But the number of affected parks and conservation areas jumps to more than 2,100 after accounting for the band of impact.

That figure even caught the attention of a researcher who has worked in Africa for decades. “I was surprised by the number of protected areas that are going to be affected by these corridors,” said Tim Caro, a conservation biologist at the University of California, Davis, who was not involved in this study. “It implies that the people who are designing these corridors are not really thinking about conservation of natural resources very much.”

University of Cambridge environmental biologist América Durán said that this study could be a tool for decision makers. “It’s a really nice piece of work that identified a big problem in Africa,” said Durán, who also did not take part in this research. “With this information, those corridors being planned can be revisited” to see whether they will really provide the intended benefits, she added.

But getting these findings into the hands of donors and policymakers isn’t easy, Caro said. “There’s a real mismatch, a disconnect, between high-quality academic research like this paper and the policymakers and donors.”

Laurance echoed Caro’s frustration: “These things get talked about, but they don’t tend to get applied very much on the ground.”

And that’s what needs to happen if compromises resulting in changes to these corridors that would benefit conservation are going to take place, Caro said.

“[The study’s authors have] outlined the problem beautifully. The next step is we have to make policymakers aware of this issue,” he said. “We have to do it quickly because these huge decisions are being made very rapidly on the continent.

“That’s the next challenge. It’s not so much doing the sophisticated analyses. It’s doing the public relations.”

Citation:

• Laurance et al., Estimating the Environmental Costs of Africa’s Massive ‘‘Development Corridors’’, Current Biology (2015), http://dx.doi.org/10.1016/j.cub.2015.10.046

Article published by Morgan Erickson-Davis

Deforestation, Economy, Environment, Featured, Forest Loss, Forests, Habitat Destruction, Habitat Loss, Infrastructure, Protected Areas, Rainforests, Roads, Tropical Forests

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