Tougher Than They Look: Wildflowers Mix It Up to Survive Drought

Lupine and California golden poppies are already blooming everywhere. They’re more than beautiful, and tougher than they look: Wildflowers can teach us a lot about surviving drought.

A new study shows wildflowers employ a mixture of strategies, some intentionally risky and others cautiously conservative, both above-ground and below, to thrive in conditions that can vary widely from year to year. With climate change making drought more frequent and more severe, this work hones the ability of land managers to predict which plants will thrive in which ecosystems in the future.

People who manage regional parks, restore former agricultural land and plant for pollinators, for example, “can take this information and decide which species they’re going to plant in a landscape where drought is becoming more common,” said Jennifer Funk, a professor in the UC Davis Department of Plant Sciences. 

Funk and team are creating this new management framework using data that other scientists have collected at more than 60 sites in the United States and around the world and catalogued in the International Drought Experiment. As a part of that project, scientists have recorded precipitation and temperature along with the traits of plants growing at those sites to see how they respond to drought. That project is funded by the United States’ National Science Foundation.

In particular, the Funk team wanted information about plants called forbs – flowering, broadleaf, non-woody plants like poppies and lupine. Then, the team dug into key plant traits – including height, root structure and nutrients stored in the leaves – in different species and ecosystems. Their result is one of the most comprehensive tools to date for predicting how which traits, in which circumstances, will help plants resist extreme, single-year drought.

“Our study shows that forbs don’t fit neatly into a simple ‘fast vs. slow’ growth model. Instead, they mix strategies,” Funk explained. 

The team found that drought-resistant forbs used some “fast” traits – such as taller stature and high levels of nitrogen in their leaves, which help plants grow and reproduce quickly before drought wears on. Plants combined those with “slow” traits such as dense roots, which help them hang on when water is scarce. In other words, forbs paired rapid aboveground growth with robust belowground investment.

Even cooler, Funk added, “The idea originated as a graduate seminar, and many of the co-authors are students from that class!” The team’s paper detailing their findings was published Feb. 11 in Nature Ecology and Evolution. Samantha Worthy, a former postdoctoral scholar in the UC Davis Department of Evolution and Ecology, was lead author on the paper. Contributors from the Department of Plant Sciences included graduate students Brooke Wainwright, Anca Barcu, Katherine Brafford and Jennifer Cribbs, and postdoctoral scholar Justin Luong.

“Graduate students are eager to get hands-on experience working with large datasets, and this project allowed us to combine drought-response data from the International Drought Experiment with publicly available plant trait data from several online databases to ask several interesting questions,” Funk said.

Different pathways to survival

The team found that taller forbs suffered less in short-term drought. Height helps plants compete for light, and this advantage increases when their leaves contain more nitrogen — an essential nutrient for photosynthesis, maintaining their DNA and growing. Together, these traits support a “drought escape” strategy.

Root systems also played a key role. Plants with larger roots can recruit fungal “partners” in the soil that help them pull in water and nutrients. Others produce long, thin roots that explore more widely and draw in additional resources. However, both tall growth and large roots require significant energy investment, posing trade-offs. In addition, root traits mattered most when combined with other plant traits.

Environmental conditions also shaped how traits mattered. High leaf nitrogen improved drought resistance mainly when drought was mild. Under more severe or prolonged dryness, more conservative traits likely become more important.

Different species of plants combine traits in different ways, yet they showed similar drought resistance, suggesting multiple pathways to survival.

Trait effects were strongest in annual plants, whose success depends on current environmental conditions. In contrast, grasses and perennials showed weaker links between measured traits and drought response. These plants may rely more on stored reserves, clonal growth or other traits not measured in the study.

“There’s no single best drought strategy. What works depends on the environment,” Funk explained.

Next up: Funk and collaborators are looking at the traits of seeds to see which ones lead to more reliable germination in dry areas.

Related links

Read the paper here: “Growth form and lifespan of herbaceous species mediate the role of traits in short-term drought response.” Jennifer Funk was the lead investigator on the research. Information used in this paper came from the International Drought Experiment and includes data collected by many researchers around the world, including Justin Luong while a Ph.D. student at UC Santa Cruz; Luong contributed to this paper while a postdoc in the Funk lab. IDE data contributors also includes a team led by Amelia Wolf of the University of Texas, Austin.

The International Drought Experiment (IDE) was a four-year project to create a global network of data describing how plants respond to drought in all kinds of ecosystems. The data collected is available to scientists, with the goal of identifying patterns of responses and understanding the mechanisms underlying those patterns. The IDE was funded by the National Science Foundation, which was created by the United States Congress in 1950 to promote progress in science. Learn more about the IDE here.

This news article was written with the assistance of artificial intelligence. All material was edited and reviewed for accuracy by real human beings before publishing.