By Chris Sasaki

As the global climate crisis continues, scientists are measuring its effect on myriad species to understand the impact of rising temperatures.

As oceans become warmer and more acidic, researchers study the increased bleaching of corals; as arctic ice cover disappears, they study the effect on the ability of polar bears to hunt. They also see the impact of global warming on plants as they evolve to become hardier or die out, or as their ranges shift in response to rising temperatures or arid conditions.

Now evolutionary ecologists have advanced our ability to accurately predict the effect of rising temperatures on plants with the unexpected discovery that competition between different species can improve a species’ ability to adapt to a warming climate.

“Researchers typically don’t consider species interactions or whole communities when studying how plants evolve in response to warming,” says Takuji Usui, a postdoctoral researcher in the Department of Ecology & Evolutionary Biology and co-author of a study describing the discovery.

“We often think of organisms evolving on their own. Also, we tend to think that competition is a negative thing—with organisms fighting for light, nutrients and space,” says Usui.

This work shows that you can’t just look at species evolving in isolation; you have to consider community context as well.

“But our study reveals that the presence of competitors acts as a catalyst to speed up adaptation to a warming climate. We’ve shown that two traits—the ability to compete and the ability to adapt to rising temperatures—can be associated and evolve hand-in-hand.”

“This work shows that you can’t just look at species evolving in isolation; you have to consider community context as well,” Usui continues. “It shows that interacting species can fundamentally shape how organisms respond to rapid, environmental change. Without this understanding, predictions about how species respond to global warming won’t be accurate.”

Usui is an evolutionary ecologist who, in EEB, works with Megan Frederickson and Stephen Wright. His research focuses on how ecological and evolutionary processes together shape the geographical distribution of species, as well as patterns of biodiversity—particularly in an era of rapid global change.

The research is described in the paper, “Competition Enables Rapid Adaptation to a Warming Range Edge in a Model Plant Community,” published in the journal Science. Usui’s co-author is Amy Angert, a population and evolutionary ecologist in the University of British Columbia’s Departments of Botany and Zoology.

Usui and Angert conducted their study using duckweed, a common aquatic plant with a tiny leaf which floats on the surface of the water and a root that hangs down from it. Found growing together in mats on ponds, rivers and lakes around the world, duckweed makes an ideal model organism for the lab because a single generation lasts only two to five days.

Usui and Angert conducted their experiment by placing duckweed species from one genus, Lemna, in climate-controlled, aquatic “pondscapes” that simulated the plants’ natural habitat. In half of all pondscapes, they also added a duckweed species from a different genus, Spirodela, which competed with the Lemna species for light, nutrients, and space. Finally, submersible heaters allowed them to simulate warming temperatures.

The experiment showed that after 10 to 15 generations, adaptation to warming occurred only for the Lemna duckweed exposed to competition.

“We found that the ability to survive warmer temperatures evolved in lockstep with the plant’s ability to compete,” says Usui. “Selecting for one trait selected for the other; the two traits seemingly evolved together.”

For Usui and Angert, the next step would be to show that this is happening in nature, outside the lab.

“It would be very valuable to track populations over long periods of time to accurately see what’s happening,” says Usui. “We can do experiments in the lab and formulate theories, but testing those ideas in a natural setting would be productive and exciting.”

“Organisms may face extinction if they can’t evolve in response to ever-warming temperatures,” says Usui. “This work highlights the urgency of including community context in predicting that response and the importance of more research.”

Originally published August 25, 2026, on University of Toronto Faculty of Arts & Science News.