The plants in our backyards do more than add beauty – they support local insects and thrive, or struggle, depending on the climate. As temperatures shift and rainfall patterns become less predictable, the timing of when plants bloom and insects emerge is changing.

Emily Meineke, assistant professor with the Department of Entomology and Nematology, and her team created the Climate Adaptation Living Lab, or CALL Garden, to study which plants can withstand changes in climate while continuing to support insects. The project is a collaboration with the UC Davis Arboretum and Public Garden and its Climate-Ready Gardening Program, which promotes sustainable horticulture and recommends species that do well in today’s shifting climate.

Researchers are testing different water levels to see how a selection of plants, and the insects that visit them, respond. The goal is to share these findings with communities so home gardeners can make informed choices about the plants they include in their yards.

“The world is becoming increasingly more urban, especially California, and increasingly the places that plants and insects have to live are around our homes, and it's actually where we can have the most environmental impact,” said Meineke.

Researchers are focused on how temperatures and rainfall affect when insects emerge and interact with plants. By testing different watering techniques on native and non-native plants, they aim to understand which plants will support insects while using water efficiently.

“If you drought-stress a plant, does that then affect who visits it; who eats from it? Does it affect bees? Does it affect caterpillars? Does it affect not only what plants that they prefer, but how they perform on those plants? Those are the kinds of questions we're interested in asking,” Meineke said.

Long-term research garden

The project is funded in part with the National Science Foundation's Faculty Early Career Development Award that Meineke recently received. The garden is located behind the Arboretum’s teaching nursery on campus. Construction started during the summer of 2023, when dozens of Arboretum staff and volunteers helped clear a large section of land to make way for 40 raised beds, each equipped with irrigation systems.

Lauren Azevedo-Schmidt, a postdoctoral researcher in Meineke’s lab, has done extensive work into understanding the impact of modern global climate change on plant-insect interactions. In early December, she led a group of volunteers and fellow researchers as they planted 200 plants in the raised beds. She said each bed has these five plant species growing in the space:

• Mugwort – hardy, drought-tolerant herb with scented foliage
• Black sage – fragrant shrub that thrives in dry conditions
• Snowberry – shrub with white berries that attracts birds and insects
• Sneezeweed – perennial with yellow flowers to support pollinators like bees
• Phacelia – drought-tolerant plant with nectar-rich blue flowers

Various water treatments

The plants are getting various water treatments that simulate both past and future climate scenarios to see how the different watering practices affect plant and insect interactions. The control treatment replicates the historical watering conditions these plants have received in the past. The team will gradually stress the plants by adjusting water availability throughout the growing season.

Another treatment predicts future water regimes, designed to reflect the more intense weather patterns anticipated due to climate change. The plants will experience drought stress followed by bursts of water – which researchers call “pulse stress.”

“It's not just that we're going to get drier, but the rain events are becoming more intense when they are happening,” Azevedo-Schmidt explained. “We're going to do what’s called pulsing, so we're not just depriving them of water completely, but when we have water, it's coming in these bursts, so lots of water and then nothing for a while.”

There will also be an ambient water treatment, where some plots receive the amount of water they would naturally get from rainfall.

“We're also curious about what summer watering is doing to the quality of the plants, because if a plant isn't putting out as many flowers because it's not watered as much during the summer, it's probably not as useful to a bee, so we want to quantify some of that,” Meineke said.

Researchers also built hoop houses to protect some of the plants by controlling environmental conditions and keeping animals like rabbits away. That also helps ensure precise watering. Azevedo-Schmidt said the team is tracking changes in insect communities this growing season and will continue collecting data over the next three years.

“Looking at all these different kinds of intersections of how plants and insects are interacting is super important because it's not just one straightforward way that insects are interacting with their food source, whether it's pollen, nectar or leaf material itself,” Azevedo-Schmidt said. “That's what we're looking at, so we can hopefully understand the effects of drought and climate change and how they're going to be affecting these plants.”

Connecting science and art

Meineke is also adding an element of art to the project. Students taking her undergraduate course, ENT 001 – Art, Science and the World of Insects, are creating a series of panels that will come together as one large mural displayed at the CALL Garden. Each piece is about 15-feet long and 5-feet tall and represents different regions of California – from the coast to the Sierra Nevada – highlighting the unique plant and insect communities in each area. 

Students, faculty and staff recently started installing a portion of the mural. Meineke said the artwork visually connects the research with the biodiversity shaped by California's varied climates.

“From the coast to the mountains, we have such a biodiverse state, and a lot of that is dictated by water availability, so we wanted to show that in a mural,” Meineke said. 

Along with the vibrant artwork, an important aspect of this project is making sure the community can benefit from what the researchers learn. By sharing their findings with Arboretum visitors, including through regular plant sales at the nursery, Meineke and her team hope to encourage people to select plants that will flourish in a changing climate while also supporting insects and wildlife.

“It's very important; if we were all cognizant of these things, we would have big populations of healthy plants that can survive into this non-analog climate and plants that are going to support food webs,” said Meineke. “We have huge swaths of residential and neighborhood areas, and parks, where we can take all of this great information that the Arboretum has and translate it into real biodiversity adaptability.”