Assoc Prof Ryan Chisholm recognised with George Mercer Award
Associate Professor Ryan Chisholm from the NUS Department of Biological Sciences (DBS) received the prestigious 2025 George Mercer Award for the paper “Unveiling the Transition from Niche to Dispersal Assembly in Ecology,” published in Nature on 7 June 2023. He received the award with lead author Dr Lynette Loke, an NUS DBS alumni.
The George Mercer Award was established in 1948 and is awarded annually for an outstanding ecological research paper published within the past two years by a younger researcher, with the lead author of the paper being 40 years of age or younger at the time of publication.
The researchers’ paper was recognised for advancing the understanding of the effects of immigration on species coexistence in intertidal communities. The authors planned a field experiment with a novel design for manipulating immigration rates. Dr Loke executed the experiment on seawalls in Sentosa, Singapore. The authors then combined these results with models to test a classic hypothesis about community assembly versus a novel hypothesis recently developed in Assoc Prof Chisholm's lab.
Consistent with the novel hypothesis, the authors showed that the number of niches in a habitat sets a low floor rather than a high ceiling on the number of coexisting species — and that there appears to be no ceiling at all if new species arrive rapidly enough. The results support the view that most species coexist transiently, not stably, and that coexistence is maintained by ongoing immigration.
The integration of field experiments with clear hypotheses and mathematical modelling provides novel insights that advance the understanding of the forces structuring ecological communities. The researchers also combined theory and empirical evidence in a creative and exceptionally well-written way.
