Scientists at the National University of Singapore (NUS) have adopted a new statistical method to uncover the extent of biodiversity loss in Singapore over the past two centuries. This study paints the most accurate picture to date of the ecological impacts of deforestation and urban development in a tropical city-state.
Led by Associate Professor Ryan Chisholm of NUS Faculty of Biological SciencesThe research team has compiled over 200 years of biodiversity records for Singapore, including over 50,000 individual records and over 3,000 species across 10 major taxa.
From this comprehensive dataset, the study estimated that 37 per cent of the species had been lost in Singapore. Importantly, the new statistical model the researchers used took into account “dark extinctions” – species that went extinct before they were discovered and recorded. Although 37 percent is a high extinction rate, it is only half of the previous estimate from 2003, which also took into account the Dark Extinction. The researchers also found that certain groups are particularly at risk of extinction, including large mammals, forest-dependent birds, orchids and butterflies.
The discovery is detailed in a scientific paper titled “Two Centuries of Biodiversity Discovery and Loss in Singapore” published in the academic journal. PNAS On December 11, 2023.
Make more accurate estimates using new statistical models
“By using statistical models developed in my lab, we can now explain species that go extinct before we know they exist. The new MODGEE (Detection Matrix Provides Extinction Estimates) model It is particularly powerful because it takes into account the entire detection history of ,” said Associate Professor Chisholm.
While previous models used only the first and last records of each species to estimate extinction rates, the MODGEE model takes a more detailed approach by using the complete species time detection matrix, making it more enriched. analysis. The MODGEE model provides estimated probabilities and extinction dates for each species and is suitable for application to groups of species with more comprehensive data records.
Prioritize and protect charismatic species
The results of this study are important not only for Singapore but also for the broader Southeast Asia region. Extrapolating from Singapore’s historical experience, researchers predict that if current deforestation trends continue, Southeast Asia could lose 18 percent of its species by 2100. They call this the “Tropical Europe” scenario. In the future, in the region’s human-dominated landscapes, extinctions will be concentrated among large, charismatic species.
In light of these findings, NUS researchers are changing their conservation strategy to prioritize landscape-scale conservation around charismatic species, i.e., species that attract more public attention due to their aesthetic appeal or cultural significance. recommended.
“Adopting this approach not only benefits other species, but is also consistent with other conservation objectives, such as protecting carbon stocks, which are important in mitigating climate change,” Associate Professor Chisholm said. added.
In urban environments like Singapore, the researchers suggested focusing on medium-sized species such as langurs, pangolins, hornbills and butterflies that can adapt to urbanized landscapes with the right conservation support. In the wider Southeast Asia region, the focus will expand to include species such as tigers, orangutans, elephants, rhinos, and other endangered large mammals.