A potted scarlet monkeyflower can look fine one day and collapse a few days later if you forget to water it. But out in the wild, some populations of this same species made it through California’s brutal four-year drought.
The wildflowers didn’t survive because the drought “wasn’t that bad,” or because the plants found hidden water. They survived because, according to a new study, they evolved fast enough to keep up.
The researchers tracked scarlet monkeyflower populations in Oregon and California for more than a decade.
The team reports something scientists have long discussed but rarely captured in nature from start to finish: climate-driven decline, rapid genetic adaptation across the whole genome, and then recovery in some populations.
In other words, “evolutionary rescue” happening in the real world, not just in theory or in lab experiments.
“Essentially what we found is that the populations that recovered are also the populations that evolved the fastest,” said study first author Daniel Anstett, an assistant professor of plant biology at Cornell University.
A real-world case study
Evolutionary rescue has been a bit like a famous concept without a clear documentary film to match it. Researchers have shown it can happen in lab settings, and models suggest it should happen under certain conditions.
But this study is presented as the first full natural-population record that ties all the pieces together: climate change pressure, population declines, genome-wide adaptation, and then a rebound.
That matters because droughts and other extreme events are expected to become more common as the planet warms.
If some populations can evolve quickly enough to survive, it changes how we think about risk. It doesn’t make climate change harmless, but it adds a new dimension to how species might cope – or fail.
“And the genetic variation we saw, even before the drought, predicted demographic recovery five, six, seven years later,” Anstett said. “That’s astounding. That’s the crystal ball we can use to predict the future.”
Tracking monkeyflower populations
The story begins in 2010, when senior author Amy Angert at the University of British Columbia and then-PhD student Seema Sheth, now at North Carolina State University, started tracking variation in monkeyflower populations in Oregon and California.
They weren’t setting out to catch a historic drought. They were doing careful long-term work, the kind that often pays off only later.
Then California’s drought arrived in 2012. The study notes it was the most extreme drought in more than 10,000 years. Populations began to shrink. Some hung on. Some struggled. Some disappeared.
As conditions worsened, the researchers realized they had something rare: a “before” snapshot they could compare against the “after.”
Even better, they had stored seeds back in the lab, essentially a biological archive of what these populations were like before the climate slammed them.
A way to watch evolution unfold
Using pre-drought data, Anstett and the team built a genetic baseline by sequencing whole genomes across 55 populations.
They didn’t just look for random differences. They paid special attention to genetic variation linked to climate differences across the plant’s range.
That gave them a map of “climate-associated sites” in the genome – places where natural selection might push change when drought hit.
Then they watched what happened as the drought unfolded. Populations declined. Genetic patterns shifted. Some groups adapted enough to survive. Others did not.
“Really, this is a story of successes and failures and the different strategies that came about, some of which were more successful than others,” Anstett said.
“Evolution has no foresight – it’s a process the same way gravity is a process.”
The team found that three populations did especially well. These were the populations with the strongest adaptation at those climate-associated genetic sites.
In plain terms: the ones whose genomes shifted the most in the “right” drought-related direction were the ones that later looked healthiest.
Mysterious survival genes
The researchers can’t yet point to a neat list of “the drought genes.” But they have clues about what kinds of traits might be involved.
Anstett said the changes seem to correlate with differences in stomata – tiny pores on leaves that open and close to control water loss and carbon uptake – as well as how the plant handles carbon during photosynthesis.
Those are exactly the kinds of traits you’d expect drought to pressure. If a plant can limit water loss without starving itself of carbon, it has a better shot.
Still, the study is careful here. The team sees signals, but the precise genes that control these traits remain unknown.
“That’s a starting point for further research. Identifying the genes involved in this evolution would help us understand what traits allow populations to survive these extended drought periods,” Anstett said.
“There also isn’t a final verdict on whether the genetic adaptation that occurred during the drought helps in the long-term. We’re still working on that.”
That last point is important. A traitù that helps in a drought might come with tradeoffs when conditions change. Evolution can solve one problem and accidentally create another. The study doesn’t pretend those risks are settled.
Implications for conservation planning
The team’s “crystal ball” claim is what could make this work especially useful. If genetic variation measured before an extreme event can predict which populations will bounce back years later, that’s potentially powerful for conservation planning.
It suggests scientists might be able to scan at-risk species, identify populations with better adaptive potential, and prioritize those for protection – or use them as sources for restoration.
“This is one species, but it’s a really good indicator for drought adaptation,” Anstett said.
“Conservation is a complicated calculus, and this gives greater information to decisionmakers that can be integrated with other types of knowledge – it’s another arrow in our quiver to try to conserve species.”
It’s not a promise that evolution will always rescue species. Plenty of populations in this study still declined or disappeared.
But the research does suggest that, for some organisms, genetic tools might help us see resilience coming before it becomes obvious on the ground.
The work continues
Anstett’s lab is now using monkeyflower seeds from 2017 to 2025 to figure out what happened after recovery and whether recent evolution changes how populations will respond to future climate events.
That’s the next question: not only “did they survive,” but “what did survival cost,” and “does it make them stronger or more fragile for the next shock?”
For Anstett, the project has also been personally huge – a long, messy, creative stretch of research that pulled him deeper into genomics.
“It’s a highly creative process ultimately, which is not something you’d expect, but you’re always finding new ways to handle the data,” he said.
“This study also just became such a big part of a lot of people’s lives – my wife is second author, so we collaborated on this, and we all worked through the pandemic. A lot of lives were intertwined with this research.”
The drought was extreme. The losses were real. But the study’s core message is surprisingly hopeful.
Sometimes, evolution moves fast enough to matter on the timescale of climate change – and if we learn how to spot that potential early, we might get better at choosing what, and where, to save.
The study is published in the journal Science.
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