- A new study rates the risk that existing and planned roads pose to tigers, wolves and other apex predators around the world.
- In the case of Nepal, the study also identifies sloth bears, wild dogs and clouded leopards as among the animals most at risk.
- The new Postal Highway being built in the nation’s south could impact eight major protected areas in Nepal and five transboundary protected areas in India.
- The threats posed by roads to wildlife include vehicle collisions, habitat fragmentation, and increased poaching pressure.
KATHMANDU — Nepal entered 2022 with encouraging news related to its tiger population. As a census gathered pace, Bardiya National Park, home to 87 of Nepal’s estimated 235 tigers, received the TX2 Award for doubling the population of the endangered species since 2010.
Amid the celebrations, conservationists feared the precariousness of that success as they had just mourned the death of a 10-year-old female Bengal tiger (Panther tigris) in central Nepal just a year ago. The incident had once again highlighted one of the biggest threats to biodiversity and wildlife in the country: Roads, both existing and those being planned. At least four tigers have died on the country’s roads in the past six years.
“Tigers, along with sloth bears and dholes [Indian wild dogs] are the three top-level predator species at most risk from current roads in Nepal,” says Bibek Raj Shrestha, co-author of a recent study published in Nature on the impacts of existing and planned roads on apex predators in different parts of the world, including Nepal. “New roads being built in the Terai [Nepal’s southern plains] put additional species such as clouded leopard, striped hyena and leopard at risk.”
When roads run close to protected areas, wildlife are threatened not just with being hit by vehicles. They also face the fragmentation or loss of their habitat, reduced genetic connectivity, and increased poaching, say the authors of the research highlighting the possible effects of existing and planned roads in Nepal, Brazil and Africa. Roads also give access to illegal loggers, land grabbers and wildlife traffickers.
“Apex predators regulate the ecosystem … If they are impacted, the whole biodiversity and the habitats are affected. That is why we decided to study apex predators,” said study co-lead author Itxaso Quintana, a research associate with the Biodiversity and Development Institute in South Africa. The study was conducted under a collaboration between graduates of the Erasmus Mundus International Master in Applied Ecology program.
Nepal’s apex predators will be gravely threatened if the country pushes ahead with a plan to build the 1,792-kilometer (1,113-mile) Hulaki Highway (Postal Road), the researchers say. The route traverses the country’s southern lowlands, where around 795 km (494 mi) has already been built. But controversy over the road cutting through protected areas has delayed its completion.
“The Postal Highway, if completed as planned, will deal a devastating blow to the Terai Arc Landscape [TAL], which bridges protected areas and habitat corridors allowing the connectivity of large-mammal metapopulations,” Shrestha told Mongabay. The TAL is a landscape-scale conservation effort initiated by the Nepali government and WWF Nepal. It extends across the nation’s southwestern region and serves as a stronghold for both the sloth bear and tiger populations.
Segments of the new highway will cross areas rich in apex predators in the central part of the Chitwan-Parsa protected area complex, as well as the western section of Suklaphanta National Park, Quintana said.
For the purposes of the study, the team identified 36 mammalian carnivores as apex predators, including clouded and snow leopards, Asiatic black bears, and striped hyenas. To review how existing road networks impact these species, Quintana and her team collected published reports on wildlife-vehicle collisions and carried out systematic searches in popular journal article catalogs. The records they found spanned a period from 1963 to October 2021.
“We were surprised to see that big animals were being killed in large numbers on the roads. A large number of leopards, pumas and Iberian lynx have died due to vehicle collisions around the world,” Quintana said.
The team also used global road density maps, IUCN global predator distribution data, and the World Database on Protected Areas to develop a method for assessing the risks posed by roads to predators.
“It was shocking that eight out of 10 apex predators impacted by roads were found in Asia,” Quintana told Mongabay. “Whenever we talk about roads, we think about North America and Europe, but we found that most of the effects are being seen in South and Southeast Asia, regions rich in apex predators.”
The researchers also assessed the potential impact of major future road projects in three regions — the Brazilian Amazon, Nepal and Africa — based on their importance for apex predator species conservation and the availability of data on proposed roads.
According to those findings, if Nepal’s Postal Highway is built as planned, 16.5% of the highway’s length will pass through a proposed conservation area and four existing national parks, including their adjacent buffer zones. If a 10-km (22-mi) buffer is added, the highway will impact eight protected areas in Nepal and five transboundary protected areas in India, the study says. The road will cross the distribution area of seven apex predator species: Himalayan wolves, clouded leopards, striped hyenas, leopards, tigers, dholes, and sloth bears.
Conservationist Hem Sagar Baral, head of the Zoological Society of London’s (ZSL) Nepal office, said the study should be an eye-opener for the country’s policymakers. “Nepal made tremendous progress in wildlife conservation over the past few decades,” he said. “But now we are taking the animals for granted.”
Baral said roads are being built across Nepal without consideration for the country’s wildlife. “In addition to the Postal Highway, the government is working on the Mid-hill Highway as well as the Madan Bhandari Highway,” he said. “If an animal moves from Nepal’s southern plains to the northern hills and mountains, it will have to pass through at least three east-west highways. Tigers could be the ones making these journeys as they move north due to climate change.”
Baral said the government is dramatically escalating road construction on the assumption that connecting settlements with roads will automatically usher in prosperity. But “roads alone don’t guarantee prosperity,” he said. “We need programs that improve the people’s standard of living.”
Plots of land connected to roads do fetch better prices than those not connected to one, and land prices in Nepal’s major urban centers have skyrocketed in the past few decades. But that hasn’t guaranteed a rise in the standard of living for rural people.
Compounding the problem of roads being built through wildlife habitat is the government’s reluctance to pay major compensation to private landowners for building roads through their property, Baral said. “Officials don’t want to spend on compensation. That is why they choose to build roads through forest areas [that are] under the ownership of the government,” he said.
Shrestha said he hopes the new study will help decision-makers rethink their Postal Highway plans. “The best thing would be to not enter protected areas at all. But if that’s not possible, we need to build infrastructure such as under- and overpasses and safe passages for wildlife,” he said, but added that these can be costly.
Biraj Shrestha, who specializes in wildlife-friendly infrastructure, said such efforts are possible only when governmental agencies coordinate with one another. “Policymakers and implementing agencies [often] only realize that infrastructure needs to be made wildlife-friendly only after the project nears completion,” he said. “That is why we need a separate agency to ensure that infrastructure is built in a wildlife-friendly manner.”
Quintana, I., Cifuentes, E. F., Dunnink, J. A., Ariza, M., Martínez-Medina, D., Fantacini, F. M., . . . Richard, F. (2022). Severe conservation risks of roads on apex predators. Scientific Reports, 12(1). doi:10.1038/s41598-022-05294-9
Feedback: Use this form to send a message to the author of this post. If you want to post a public comment, you can do that at the bottom of the page.
Banner Image: Busy traffic seen on a road passing through a forested area in Nepal. Image courtesy Krishna Dev Hengaju/IUCN