Scientists develop novel method to estimate biodiversity loss in Singapore over the past two centuries

Led by Affiliate Professor Ryan Chisholm from the NUS Division of Organic Sciences, the analysis workforce compiled over 200 years of biodiversity data for Singapore, encompassing greater than 50,000 particular person data and over 3,000 species throughout ten main taxonomic teams.

From this complete dataset, the examine estimated that Singapore has misplaced 37 per cent of its species. Importantly, the novel statistical fashions utilized by the workforce thought of ‘darkish extinctions’ — species that went extinct earlier than they might be found and documented. Though 37 per cent is a excessive extinction charge, it is just half that of a earlier 2003 estimate that additionally tried to account for darkish extinctions. The workforce additionally discovered that sure teams are significantly susceptible to extinction, together with bigger mammals, forest-dependent birds, orchids and butterflies.

The findings had been detailed in a scientific paper titled “Two centuries of biodiversity discovery and loss in Singapore,” revealed within the journal PNAS on 11 December 2023.

Utilizing novel statistical fashions for extra correct estimation

“Using statistical fashions developed in my lab allowed us account for species which have disappeared earlier than we even knew they existed. The novel MODGEE (matrix-of-detections-gives-extinction-estimates) mannequin is especially highly effective as a result of it takes under consideration your complete detection historical past of every species,” mentioned Assoc Prof Chisholm.

Whereas earlier fashions estimated extinction charges utilizing simply every species’ first and final data, the MODGEE mannequin takes a extra detailed method by utilizing the total species-by-time detection matrix, facilitating a richer evaluation. The MODGEE mannequin offers estimated possibilities and dates of extinction for every species, and is appropriate for software to teams of species with extra complete information data.

Prioritising charismatic species for conservation

The examine’s findings are important not just for Singapore however the broader Southeast Asian area. The researchers extrapolated Singapore’s historic expertise to mission that if present deforestation tendencies persist, Southeast Asia could lose 18 per cent of its species by 2100. They describe this as a ‘tropical Europe’ state of affairs, as a result of though a big majority of species is projected to persist sooner or later human-dominated landscapes of the area, extinctions will probably be concentrated amongst giant charismatic species.

Given these findings, the NUS researchers beneficial a shift in conservation technique, prioritising landscape-scale conservation centred round charismatic species — species that garner extra public curiosity as a consequence of their aesthetic attraction or cultural significance.

“Adopting this method not solely advantages different species but additionally aligns with different conservation targets, such because the safety of carbon shares, essential in mitigating local weather change,” added Assoc Prof Chisholm.

In city settings like Singapore, the researchers advised specializing in medium-sized species resembling langurs, pangolins, hornbills and butterflies, which may adapt to urbanised landscapes with correct conservation assist. For the bigger Southeast Asian area, the main focus expands to incorporate species resembling tigers, orangutans, elephants, rhinoceroses and different endangered giant mammals.