SINGAPORE — Nearly 70 species of wildlife have been spotted using an overhead animal-only bridge near the Singapore Zoo since the crossing opened in late 2019 to reconnect two forest patches cut off by a busy road. 

Over the past 18 months, animals such as the Sunda scops owl, common-palm civet, the large-tailed nightjar (a bird) and the lesser short-nosed fruit bat have been spotted using the 140m Mandai Wildlife Bridge, the Mandai Wildlife Group said on Thursday (Feb 3).

The bridge was launched in December 2019 to link forest patches in the Central Catchment Nature Reserve. One of its aims was to reduce the risk of roadkill by allowing wildlife to cross Mandai Lake Road safely.

To encourage animals to use the crossing, the bridge is covered in vegetation — including native trees and a combination of species that grow to various heights to create a multi-layered forest structure — with permanent fencing along the road funnelling them onto the bridge.

In a statement, Ms Chua Yen Kheng, the wildlife group’s assistant vice-president for sustainable solutions, said that the project has created vital habitat connectivity and a safe passage for wildlife. 

Animals commonly found in the surrounding forests, such as the sambar deer, wild pigs, long-tailed macaques and different species of birds, have adapted well to the bridge, she added.

“When the vegetation is mature, we expect that elusive species like the lesser mousedeer and Sunda pangolins will use the bridge to move between the forest patches.” 

Mandai Wildlife Group said that the vegetation on the bridge is set to form a continuous canopy over the crossing by 2025.

To enrich the ground layer on the bridge, logs, branches and leaf litter from wildlife parks were collected and transported to the crossing. Log piles were added as stepping stones or refuge for small mammals, reptiles and amphibians. 

Saplings, salvaged from nearby sites, were transplanted to improve the diversity of vegetation. 

Saplings of Glochidion obscurum, a recently discovered and locally threatened tree species, have also been found growing on the bridge as a result of animal dispersal — a positive sign of natural regeneration of flora, the wildlife group said. 

WILDLIFE SIGHTINGS

To spot signs of animals, the group installed six cameras along the bridge as part of a long-term ecological monitoring programme at Mandai Wildlife Reserve.

This information is then used to shape environmental management and other plans for ecological restoration, wildlife connectivity improvement and population studies for the future Mandai Wildlife Reserve precinct.

The mostly nocturnal sambar deer, estimated in 2010 to have a population size of fewer than 20 in Singapore, have been spotted using the bridge almost every night.

Camera traps have recorded sightings and foraging activities of the Sunda pangolin and lesser mousedeer — both critically endangered in Singapore — near the Mandai Wildlife Bridge in the buffer zones of the development.

These buffers are vegetated tracts meant to minimise disturbance between the areas being developed and the Central Catchment Nature Reserve, thereby raising the likelihood of shyer species using the wildlife bridge. 

Some animals have also been seen using the bridge for reasons other than crossing between the two forest patches.

Changeable hawk-eagles and monitor lizards were seen using the colugo poles (artificial crossing aids for animals that live in trees) on the bridge to perch and bask in the sun. Sambar deer, long-tailed macaques and wild pigs were also often spotted nursing and nurturing their offspring. 

Red junglefowls were captured taking advantage of upturned soil left behind by foraging wild pigs — an observation that Mandai Wildlife Group said has added to its knowledge of how species interact with one another.

The Mandai area, where construction work to build new attractions is continuing, has seen a number of roadkill incidents. In 2018, a spate of road accidents that caused the death of a Sunda pangolin, leopard cat and sambar deer led nature enthusiasts to call for more preventive measures.

Yet, the opening of the Mandai Wildlife Bridge did not seem to stop animals from getting killed.

In response to TODAY's queries, Mandai Wildlife Group said on Friday that there were seven reports of roadkill incidents between January 2020 and December 2021 that happened within 500m of Mandai Road, which lies about 350m north of the bridge.

The animals that died included the Malayan colugo (also known as the Malayan flying lemur), long-tailed macaque, wild pig, red-tailed pipe snake and Sunda pangolin. These reports have been shared with the nature community as part of an ongoing engagement with community members, Mandai Wildlife Group said.

Before the bridge opened, the group had already put up fencing along Mandai Lake Road and closed the road from 1.30am to 6am daily.

This had cut the number of roadkill incidents by more than half between 2018 and 2019.

Mandai Wildlife Group added that it will keep these measures in place until the end of the project.

In addition, it had increased the number of speed humps from five to eight along the 1.4km Mandai Lake Road, which also has several other traffic-calming measures such as signs urging drivers to slow down and warning them of potential wildlife crossing.

Other safety measures include one-way hatch doors installed along the length of Mandai Lake Road to give stranded animals access to alternative routes and routine monitoring for potential breaches and gaps along the fences.

Ms Chen said that the lessons the wildlife group has learnt from designing and deploying wildlife-friendly features in a built environment would potentially be useful for projects elsewhere.

The overhead animal bridge — the second of its kind in Singapore — was launched alongside plans to revegetate a 9ha slice of degraded habitat.

The other bridge, Eco-Link@BKE, allows animals to move between the Bukit Timah and Central Catchment nature reserves without the risk of being run over by vehicles. It opened in 2013. 

When the development of the Mandai precinct is ready, it will house five parks: The upcoming Rainforest Wild, Bird Paradise — which will be relocated from Jurong — and the existing Singapore Zoo, Night Safari and River Wonders. An eco-friendly resort is also set to be built there.