- Singapore has lost most of its primary forest since the 19th century, and roughly a third of terrestrial vertebrate species have disappeared locally, often through gradual habitat thinning rather than sudden collapse.
- Snakes and lizards show a two-stage pattern of decline tied first to plantation-era deforestation and later to rapid urbanization, with forest specialists hardest hit while adaptable species persist in degraded habitats.
- Despite losses, reptiles have proven relatively resilient; many can survive in disturbed environments, but fragmented populations remain vulnerable and natural recolonization is unlikely across the sea barrier to Malaysia.
- Maturing secondary forests and restoration efforts create conditions for cautious rewilding, and scientists suggest targeted translocation—such as reintroducing the forest gecko Gekko hulk—could restore some lost ecological functions even if the original ecosystem cannot be fully recovered.
In the older quarters of Singapore, fragments of forest persist like memories that refuse to fade. Within them live creatures that few residents ever see, and some that no longer exist there at all. The disappearance of species on an island is not always dramatic. Often it happens quietly, in decades of thinning habitat and interrupted life cycles, until absence becomes normal. A snake not recorded since 1904 leaves no trace in the soil, only a line in an archive.
Singapore’s ecological history is one of compression. Since the 19th century, most primary forest has been cleared for plantations, industry, and housing. Today only a sliver of original forest remains, surrounded by a landscape remade for human needs. Such transformation has exacted a toll on wildlife, especially terrestrial vertebrates. Estimates suggest that roughly a third of species across several groups have disappeared locally over two centuries. Snakes and lizards, however, tell a more complicated story.
A recent analysis of Singapore’s squamates, the group that includes snakes and lizards, reconstructs a timeline of loss using historical records and statistical modeling. The pattern resembles two pulses of erosion. The first, in the early 1900s, coincides with the near-total conversion of primary forest. A second, smaller wave arrives late in the 20th century, as remaining secondary forests give way to rapid urbanization. Primary-forest specialists suffered most. Species able to tolerate degraded or managed landscapes fared better, some persisting in the ecological margins.
Yet reptiles proved unexpectedly resilient compared with birds and butterflies. About 17% of native squamate species appear to have been extirpated, a significant figure but lower than for many other groups. Their biology may partly explain this. Many reptiles require sunlit microhabitats for thermoregulation and can survive in disturbed environments where such conditions are common. Survival, however, does not imply security. Small, fragmented populations linger at the edge of viability, vulnerable to further disturbance and chance events.
Unlike birds or mammals, most reptiles cannot easily recolonize the island. The narrow strait separating Singapore from mainland Malaysia is a formidable barrier to creatures that neither fly nor travel far over water. Any return of vanished species in the near term would therefore likely depend on deliberate human intervention. Conservationists call this “translocation,” though the term understates the ambition: rebuilding ecological relationships that have been absent for decades.
Here the story turns, cautiously, toward recovery. Singapore’s secondary forests have matured over the past century, developing dense canopies and complex understories. Active restoration programs now accelerate this process, and hunting pressure is relatively low. In recent decades, several species once thought lost have reappeared or recolonized naturally. The landscape, though altered, is not biologically empty.
The authors, Ananthanarayanan Sankar and Ryan A. Chisholm of the National University of Singapore, identify a forest gecko, Gekko hulk, as a plausible candidate for reintroduction. It vanished only recently, persists in nearby Malaysian forests, and feeds on a wide range of insects. Suitable habitat still exists in Singapore’s nature reserves. If returned, it could resume its role as a mid-level predator, restoring small threads of ecological function.
The idea is sobering. Reintroduction cannot recreate the past; the island of 1820 is gone beyond recall. But it suggests that extinction, at least at the local scale, need not always be final. In fragments of forest bordered by expressways and apartment towers, life is learning how to return.
Citation:
- Sankar, A., & Chisholm, R.A. Where will they come from, when did they go? Squamate extirpations and recoveries in Singapore. Biological Conservation 315, 111721 (2026). https://doi.org/10.1016/j.biocon.2026.111721
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