Our lab’s research seeks to explore the causes and consequences of biodiversity across the world. Our research involves a combination of mathematical modelling, computer simulation, statistical analysis and fieldwork.

Mechanistic biodiversity models
Species diversity varies enormously across the world. For example, aseasonal tropical forests can contain over a thousand species in a 50 ha plot, while seasonal tropical forests may have fewer than 100 species and temperate forests may have only a dozen. At regional scales, large turnover of species composition can occur within a few hundred kilometres or a few thousand years. Despite the bewildering complexity of these multi-species systems, regular statistical patterns of species richness, abundance and turnover often emerge. This suggests that a broad understanding of biodiversity can be obtained from relatively simple models if we can only identify the most important mechanisms. We seek to build such models and test them against large data sets. We also use these models to explore the potential effects of human actions, such as habitat destruction, on biodiversity.

Biodiversity–ecosystem function models
The relationship between biodiversity and ecosystem function is of long-standing interest in ecology. Do communities with higher diversity function better, for example in terms of their ability to take up and store carbon? This question has been explored extensively in grasslands, but our understanding of forests lags. We are building theoretical models to explore what mechanisms can explain complex scale-dependent relationships between diversity and function observed in forests.

Malayan Horned frog (Megophrys nasuta). Photo by Prarthini Selveindran.

Estimating historical extinction rates
A large number of species are known to have gone extinct in recent centuries, locally and globally. But these known extinctions are only part of the story. Because species discovery is also an ongoing process, many species are likely to have gone extinct before they could become known to science. How can we estimate these “undetected extinctions”? We have built statistical models to estimate total rates of extinction, including undetected extinctions, from historical data. We have applied these models to birds in Singapore and are currently applying them to other taxonomic groups at other scales. These efforts are essential if we are to understand the full impact of human activities on Earth’s biodiversity.