The underpasses constructed along the Narayanghat-Muglin road section have eased the movement of wild animals in the area, a study has shown.

According to the findings of the study, Usage of Man-Made Underpass by Wildlife: A Case Study of Narayanghat-Muglin Road Section, various animals have been sighted using these underpasses to get across the busy road section.

Researchers had deployed the camera trap method to assess the effectiveness of the underpasses in wildlife movement, and they discovered several animals using these subways to get from one side of the road to another.

In an effort to minimise roadkills, four underpasses have been constructed at Narayanghat-Ramnagar and Ramnagar-Jugedi segments of the Narayanghat-Muglin road section which connects Prithvi Highway and East-West Highway.

“I have been watching the construction of these underpasses since the beginning. Our sole motivation behind the study was to check its functionality in facilitating the movement of wild animals,” Santosh Poudel, one of the co-authors of the study, told the Post. “There have been sightings of wild animals using them.”

A study conducted in 2016 had found that the forest corridor hosts 33 species of mammals, 328 species of birds, 37 species of fishes, 16 species of butterflies, 31 species of herpetofauna, and 199 species of plants.

The study also concluded that heavy vehicular movement along the highways, including the Narayanghat-Muglin section, that transects the corridor made wild animals vulnerable.

The underpasses were constructed in 2018 in Aaptari and Ramnagar areas of the Narayangadh-Muglin road section which bisects Barandabhar Corridor Forest—a wildlife corridor connecting Chitwan National Park with the Mahabharat foothills.

Two underpasses have been built nearly 1.5 km north of Aaptari and the other two about 2 km north of Ramnagar. Each underpass measures 4 metre wide and 5.5-metre high.

The camera traps that were installed for the latest study captured a total of 567 images. Of the total images, 214 (37.74 per cent) were of animals. A total of seven species of mammals—wild boar, common leopard, barking deer, spotted deer, Asian palm civet, Indian crested porcupine and yellow-throated marten— were sighted using the underpasses. Among them, wild boars were the most frequent wanderers.

“Our findings have proven that these underpasses have been working effectively and helping wild animals avoid getting hit or run over by vehicles,” said Poudel. “One leopard was seen first going through the underpass and then also returning from the same route. This shows that the underpasses are functioning the way they are meant for, to connect habitats divided by the road.”

Construction of these underpasses were questioned for not being convenient to large animals like rhinos and elephants. This study did not capture any rhinos, tigers or elephants using the structures.

“These underpasses are the first one in the country. Even though they are not appropriate for large animals, small animals are using them, which is good. Earlier, there were no such measures to prevent roadkills, now we have them,” said Baburam Lamichhane, a wildlife researcher, who also co-authored this study. “We can learn from these underpasses and consider issues when building them elsewhere.”

Wildlife roadkill prevention has been a major challenge in the country where highways traverse through major protected areas.

According to Lamichhane, nearly 100 wild animals are killed in vehicle-wildlife collision incidents.

“Such incidents are particularly high in Bardiya and Banke national parks compared to Chitwan National Park and adjoining corridors,” said Lamichhane, chief of Biodiversity Conservation Centre, Sauraha, under the National Trust for Nature Conservation.

In the fiscal year 2016-17, a total of 133 animal casualties, including a male tiger in Bardiya National Park, were recorded due to road accidents. Besides wildlife casualties, habitat fragmentation due to man-made structures such as roads are also known to alter the behaviour of animals.

A study conducted in Barandabhar Forest Corridor found that the vehicular movement along the East-West Highway had been obstructing tigers’ movement from adjoining forests and buffer zones of Chitwan National Park. Tigers were not venturing to the other side of the highway due to heavy traffic movement.

Wildlife conservationists have long been calling on the authorities to develop infrastructures facilitating wildlife movement.

As a result, four underpasses are currently being constructed along the Naraynghat-Butwal section of East-West Highway. Underpasses are also being planned for the Narayanghat-Pathlaiya section of the highway, according to Lamichhane.

In 2019, the Department of National Park and Wildlife Conservation developed a standard for roads—including major national highways—which traverse through forest areas and protected parks of the country for maintaining a set of standards for ensuring wildlife safety.

The study, confirming wild animals frequently using the existing underpasses, supports the necessity of similar measures while constructing roads that pass and traverse the wildlife habitats like Barndabhar Forest Corridor, researchers said.

“Roadkills along this road section have gone down in comparison to the past. The government should conduct a prior study to identify wildlife species in the habitat and their natural routes,” said Poudel. “Such studies can help in the design of animal-specific measures and identify locations often used by animals.”