In satellite images, once continuous forests are now fragmented by crisscrossing highways and urban blocks, resembling a green tapestry torn apart by a blade. Approximately 40% of the world’s terrestrial ecosystems have been divided by transportation and infrastructure (WWF data), and in some areas, this fragmentation has nearly fatal consequences for wildlife. For instance, in Malaysia, cameras have repeatedly captured tigers pacing along the edge of the forest, just a few meters away from the roaring traffic – they are unable to safely cross this barrier, leading to a continuous reduction in their foraging range and reproductive opportunities. In California, USA, due to highways cutting through their habitat, the genetic diversity of certain mountain lion populations has dropped to an all-time low, and scientists warn that without intervention, they could face extinction within decades. This “habitat fragmentation” not only leads to a sharp decline in population numbers but also undermines the overall stability of ecosystems. To address this challenge, since the 1980s, Europe and America have taken the lead in proposing and implementing the concept of “wildlife corridors” – through specially designed green bridges, ecological tunnels, and corridors, allowing animals to safely cross the barriers of human infrastructure and restore ecological connectivity. This concept has now spread globally, from the cedar forests of the Rocky Mountains to the tropical rainforests of Southeast Asia.

Eco-Link@BKE in Singapore is the first wildlife bridge in Southeast Asia, which was put into use in 2013. It spans the Bukit Timah Expressway (BKE), reconnecting the Bukit Timah Nature Reserve and the Central Catchment Nature Reserve that had been separated by the road for decades. After the expressway was built, the once-intact tropical rainforest was forcibly cut off, and the migration routes of animals such as pangolins, long-tailed macaques, squirrels, and monitor lizards were blocked, limiting gene exchange. To repair this rift, the government built a 62-meter-long, gracefully arched green bridge, covered with native trees and shrubs, to simulate the natural forest environment as much as possible. High fences and buffer zones are set up at both ends of the bridge to isolate the noise and light pollution from the traffic. Monitoring data shows that more than 20 species of animals have safely crossed the bridge since its opening, and the number of roadkill incidents has decreased by over 80%. The activity range of some small mammals has expanded by more than 30%. Infrared cameras have captured images of pangolins slowly crossing the bridge at night and groups of macaques crossing the bridge, vividly confirming the success of the project. Eco-Link@BKE not only restores ecological connectivity but also serves as a model case for urban wildlife corridors worldwide, being cited by many environmental protection agencies, demonstrating a feasible path for protecting biodiversity in highly urbanized environments.

Although Eco-Link@BKE has achieved remarkable results, it still faces multiple challenges. Firstly, the long-term maintenance costs of the ecological bridge are high, including vegetation care, structural repairs, and updates to monitoring equipment, which require continuous investment in funds and manpower. Secondly, the rapid urbanization process may still threaten the surrounding habitats, and new roads and infrastructure construction may again disrupt ecological connectivity. Moreover, different species have varying rates of adaptation to the new passage, and there is also potential competition among some species, which requires scientific management. To address these issues, the government not only needs to ensure long-term funds and legal guarantees at the policy level, but also should strengthen public participation by organizing school visits and science popularization lectures to enhance community conservation awareness. In the future, Singapore plans to extend this model to other key ecological corridors and combine it with artificial intelligence image recognition technology for long-term monitoring. At the same time, other Southeast Asian countries can also draw on this experience and explore cross-border ecological corridor cooperation to enhance biodiversity resilience at the regional scale.

Eco-Link@BKE in Singapore tells us that even in a highly urbanized environment, nature and humanity can still find a way to coexist. The ecological bridge not only repairs the cracks in the ecosystem but also provides a feasible model for addressing habitat fragmentation on a global scale. In the face of escalating urban expansion and climate crisis, only by continuously investing in ecological infrastructure and establishing synergy among policies, technology, and public participation can countries safeguard the precious life network on Earth.

By: Yi Lydia Shen