Bay Nature magazineSpring 2023

Bay Nature Local Heroes

Local Heroes 2023: Stu Weiss, Conservation Action Award

March 22, 2023
Stu Weiss, Conservation Action hero. (Illustration by Eric Nyquist)

Sometimes Stu Weiss thinks he is “in a coevolutionary relationship with the Bay checkerspot butterfly,” the orange-flecked serpentine denizen he’s studied for four decades. “It nourishes me,” he says. “I nourish it.” Creekside Science’s chief scientist is known for helping monarchs and assembling a data trove called the Conservation Lands Network, among many accomplishments. But the checkerspot will always be his muse. Hard problems give Weiss juice, and the checkerspot has posed plenty of those.

He encountered the bug at Stanford University, chasing through fields of wildflowers to catch checkerspots under renowned biologist Paul Ehrlich. Nothing could be better. He chose fieldwork over grad school, at first. Worked for Ehrlich for years, got the PhD, and eventually started Creekside, a biodiversity and conservation consultancy.

In 1984, Weiss saw how a hill’s slope could determine how much sunshine checkerspot larvae encountered. Topographic complexity could be measured, predicted—and designed for. Since his 1988 paper planted that seed, ecologists have learned such complexity imparts resilience more generally, because species can easily move to better nooks.

Another checkerspot-triggered revelation in the early 1990s: Plumes of atmospheric nitrogen from cars and power plants were changing California. Nitrogen fertilized fast-growing weeds, which choked out the checkerspot’s host plants. Cattle grazing, Weiss realized, could keep the weeds down. Nonnative species could help native ones. The idea led to his seminal 1999 Conservation Biology paper, “Cars, Cows, and Checkerspot Butterflies.” 

The 2023 Bay Nature Local Hero Awards

Every year, the Bay Nature board chooses four community-nominated leaders who are changing Bay Area nature and communities for the better. “These are folks who speak with their actions and choices over days, years, and decades and motivate us all to do the same,” writes our editor in chief, Victoria Schlesinger. Here are profiles of the other 2023 award winners:

Blanca Hernández, Environmental Educator Award

Omar Gallardo, Community Hero

Alexii Sigona, Young Leader Award

Then the checkerspot taught Weiss how to transform science into action. He was commiserating with a conservation activist about how somebody should do something. They realized that something was up to them. Weiss dove into the slippery worlds of bureaucracy and real-
estate deals. He learned that conservation’s supposed enemies—
power-plant companies, ranchers—could make fine partners. His research helped establish a legal precedent that atmospheric nitrogen emissions require mitigation. It then became the basis for a $665 million habitat conservation plan, approved in 2013, for Santa Clara County, which is checkerspot central. 

How long that took was one more lesson from the little butterfly. Saving a species is deeply gratifying, he allows—but “you’ve got to be in it for the long haul.”

Since 2006, Weiss, as the Conservation Lands Network’s science adviser, has been synthesizing—with hundreds of local experts—heaps of geographic species data, to inform upland conservation planning in the Bay Area. CLN is “a ready-made tool to look at the conservation values of any piece of land in the Bay Area,” Weiss says. Now, he adds, we need to amp up stewardship, so he’s working on a CLN 3.0 to address that.

On a January morning, Weiss stands in a South Bay eucalyptus grove he designed for monarchs. A curved row of newly planted red gums stands inside a row of red ironbarks: a growing wind block for butterflies. More nonnative species being put to use for the natives, Weiss notes, and as he talks, a butterfly flits by into the warm sun. 

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About the Author

Kate Golden is Bay Nature's digital editor. Her background is in investigative, data-driven, and science journalism, and she has reported from rural Australia to the Bering Sea. She is also an artist, cyclist and sailor. Send tips to kate at, or find her on IG at @meownderthal.