A rare desert plant shows benefits of sustainability efforts at a large solar array in the Mojave Desert

Although sunlight is one of the cleanest forms of renewable energy available, clearing large swathes of desert habitat to build solar arrays has consequences for the plants and animals it displaces. Researchers are trying to find better ways to preserve desert landscapes without impeding solar energy development. Now, a new study demonstrates that with careful planning and consideration for the ecosystem around it, at least one desert plant is surviving—and thriving—amidst the solar panels helping to power Las Vegas.

The research, published late November in Frontiers in Ecology and Evolution, was led by DRI ecologist Tiffany Pereira. She and her team monitored the Gemini Solar Project for a rare plant called threecorner milkvetch two years after solar panel installation.

Findings on plant survival

The results were striking, with 93 plants found on site in 2024 compared to 12 plants found before construction in 2018. This demonstrates that the plant’s seeds not only survived construction, but that the species returned in numbers. By comparing threecorner milkvetch plants at Gemini to those at a nearby site where the habitat was undisturbed, the research is able to relate the differences between the two populations to the solar panel’s impacts, and not just changes in weather patterns.

“We were curious to see how the seed bank would be impacted by the construction,” Pereira said. “What we found was that not only did the seed bank survive, but the plant came up. And these were big plants, they were larger in every metric we measured—width, height, number of flowers and fruits, leaf length—than the plants that we measured off the site. That was really cool and surprising.”

Conservation efforts at Gemini Solar Project

The Gemini Solar Project is unique because it made efforts to preserve the desert plants and animals on site during and after construction. Most large-scale solar arrays use a method known as “blade and grade” which involves tearing up the plants and soils before installing the solar panels. This method not only denudes the landscape, it also destroys the fragile seed bank preserved in the top layers of the soil, preventing the habitat from recovering.

For these reasons, scientists and conservation practitioners have expressed concerns about the impacts of large solar installations on fragile desert landscapes. Efforts at Gemini show that the push for renewable energy development can be better paired with habitat preservation efforts.

The plant at the center of the research, threecorner milkvetch, is a rare species in the pea family that is under consideration for listing under the Endangered Species Act. The State of Nevada has categorized it as Critically Endangered and Fully Protected, and the Bureau of Land Management considers it a Special Status Species.

Threecorner milkvetch and rainfall patterns

Like other plants in this parched part of the world, its persistence is highly dependent on rainfall. As an annual species, it can be impossible to find during dry years and then found in significant numbers when higher rainfall brings the desert back to life. It’s this relationship with water that Pereira and the study team suspect is responsible for the plant’s higher growth rates at Gemini.

“Subsequent years of monitoring will help us unpack this,” Pereira said, “but the soil moisture content on Gemini is higher after rainfall events. The water is retained in the ground for longer after rainstorms, so it takes longer to dry out. The plants might just be soaking up that extra water.”

Future research and habitat trade-offs

Pereira emphasizes that the results of this study only represent one year of surveys following construction, and that she will continue surveying Gemini for threecorner milkvetch plants to determine if this pattern holds.

Her team also noted in the study that although the plants at Gemini seemed to be thriving, they only found one plant growing in the shaded area beneath a solar panel. This could mean that there continue to be trade-offs in habitat reduction, as the species may now be limited to germinating in the limited space between solar panels. Pereira is planning to conduct a germination study to verify this limitation.

“Our main goal for land managers is always avoidance,” she said. “When it comes to rare plant habitat, avoid if possible, and then these alternative construction methods can be used to preserve habitat in areas where it can’t be avoided.”

Balancing renewable energy and conservation

The study offers hope for powering humanity’s needs with fossil fuel-free, plentiful sunlight, without sacrificing the sweeping desert vistas that are the allure of the Southwest.

“Our desert species are amazing,” Pereira said. “These seedbanks can withstand a lot—they persist in the soil for years, just waiting for the right conditions to germinate, and now we know that they can even survive through more gentle construction methods. With a little ingenuity, we can address both habitat and renewable energy concerns. These things can work together.”