Road ecology is an emerging science from the fields of landscape and ecosystem ecology and studies the adverse impact of roads on nature. It seeks to evaluate how populations of plants and animals are fragmented by road systems and how motor vehicles (and their pollution) can cause mortality and suppress fertility in both plants and animals.

Roads are a way that humans have sought to modify their environment for their benefit. Recent development debates have focused on rural roads as a headline indicator of development in impoverished regions. Under this model, physical, social and political isolation are seen as core features of the poverty trap. Thus, roads are crucial because they connect isolated communities with important markets, educational opportunities and services. Such roads may also provide rural villages with much needed access to other communities or to precious natural resources.

However, both roads and the traffic that run on these roads impact the ecology of the surrounding environment. Water quality surrounding roads is poor due to the pollutants present in the surface runoff of the roads, as well as spills and byproducts generated during vehicle use. The noise generated from traffic on the roads lead to increased heart rate and decreased reproduction for animals. In rural areas, humans can hear road noise up to 10km from the road.

Moreover, highways and roads also function as barriers for animal populations. Some roads have segmented animal populations like the cheetahs in California such that it has created two distinct populations. Such isolation reduces the gene flow and may result in ecosystem level alterations such as having insufficient herbivores to disperse seeds in a particular area.

Roadkill may also reduce the wildlife population densities and harm the survival probabilities of local population. The deaths related to traffic collisions have contributed to the decline of species like the Eurasian badger and the Florida panther. In Brazil alone, the giant anteaters have been severely devastated by roadkill. Since 2013, road ecologists have discovered 124 anteaters roadkill out of an estimated global population of 5,000.

Roads: Development vs Environment?

Now that the developed countries have benefited from the infrastructure afforded by road access, should they now impose a restriction on developing nations to curtail road construction and continue to survive with decreased accessibility and connections?

Regardless of whether we are prepared or not, massive road networks and new routes are coming. Many of the geographical areas slated for massive road networks also host our planet’s most intact habitat, e.g., the Peruvian Amazon. Even with the fiercest protests and activism, roads are highly likely to be built since they significantly improve the infrastructure of the country and lead to sustained, multiplying benefits.

Are we then doomed to accept the wildlife destruction and ecological devastation that accompany the construction of roads, particularly in ecologically dense environments?

Wildlife crossings: reducing fragmentation and roadkill near highways

The current solution for minimising the frequency of roadkill and reducing the impact of fragmentation is to install wildlife crossings across highways and roads. These are a network of underpasses and bridges that allow animals to either pass above or below roadways. In Singapore, overpasses have been erected to allow for pangolins to pass over roads unscathed. In Canada’s Banff National Park, a series of roadside fencing, underpasses and overpasses have reduced roadkill by more than 80% and permitted more than 200,000 traversals by creatures.

Watch this video on YouTube to learn more: “Wildlife crossings stop roadkill. Why aren’t there more?”

At times, the recommendation from road ecologist may be that certain roads should not be paved at all. For instance, some tracks through the Amazonian rainforest would wreak havoc over the habit and local ecosystems. In this case, wildlife crossings and fences could be a form of green-washing, i.e. a tactic used to launder (clean up) a harmful road’s environmental reputation.

However, even where governments are adamant on building roads that should not exist, a compromise may be found in wildlife crossings which minimise the disruption to the movement patterns of animals.

Questions for further personal evaluation: 

  1. What are the factors that a government should take into consideration before deciding to build a roadway? How much of a priority should wildlife protection be as a factor, if at all? Why?
  2. “Having profited wildly from a century of infrastructural growth, can the developed world deny other countries the benefits of connectivity?” Discuss.

Useful vocabulary: 

  1. unscathed’: without suffering any injury, damage or harm
  2. adamant’: refusing to be persuaded or to change one’s mind

Here are more related articles for further reading:

  1. National Geographic: Wildlife crossings protect both animals and humans

Roaring traffic doesn’t stop big mammals like moose and bears from crossing highways—nor does it keep myriad smaller creatures from being squished by car tires. In just two years along one stretch of highway in Utah, 98 deer, three moose, two elk, multiple raccoons, and a cougar were killed in car collisions—a total of 106 animals. In the United States, there are 21 threatened and endangered species whose very survival is threatened by road mortalities, including Key deer in Florida, bighorn sheep in California, and red-bellied turtles in Alabama.

People are also hurt—about 200 die every year in the more than one million car collisions in the U.S., according to the National Highway Traffic Safety Administration. These crashes are expensive, too: Deer-car collisions cost an average of $8,190, an elk-vehicle collision is about $25,319, and a moose-vehicle collision is $44,546, taking into consideration human injuries and death, towing, vehicle repair, investigation of the accident by local authorities, and carcass disposal, according to a paper from the Western Transportation Institute (WTI) at Montana State University.

And the number of these deadly accidents is growing. “Over the most recently reported 15-year period, wildlife-vehicle collisions have increased by 50 percent, with an estimated one to two million large animals killed by motorists every year,” says Rob Ament, the road ecology program manager at WTI.

  1. World Economic Forum: How roads contribute to development

Roads are the arteries through which the economy pulses. By linking producers to markets, workers to jobs, students to school, and the sick to hospitals, roads are vital to any development agenda.  Since 2002, the World Bank has constructed or rehabilitated more than 260,000 km of roads. It lends more for roads than for education, health, and social services combined. However, while roads bring economic and social benefits, they can also come with social costs such as pollution or deforestation.  The Amazon rainforest is crisscrossed by almost 100,000 km of roads—enough to circle the Earth two and a half times. And the transport sector accounts for about 23 percent of global energy-related carbon dioxide emissions and a significant share of local particle pollution. Such tradeoffs need to be weighed when planning any intervention.

Measuring the overall impact of transport policies is difficult for a number of reasons. One is the lack of data: as a general rule, the poorer the country and the greater the need for transport to support development, the less data are available. Transport services also affect almost every economic activity to a varying degree, so isolating specific impacts is challenging. Furthermore, investments often target specific areas with high potential. The counterfactual outcome without the investment is therefore usually unknown. Randomized experiments—the go-to tool in many other sectors—are possible for some transport interventions but not when it comes to major infrastructure investments. The good news is that today, we have access to an ever increasing wealth of detailed geo-referenced data which opens up new avenues for analysis.  Recent advances in the field of econometrics present new solutions to old methodological problems, broadening the scope of impact evaluations.