Denver Botanic Garden scientists are keeping tabs on how climate will change Colorado’s flora

They’re also saving seeds in preparation for a worst-case scenario.

Sprouting seeds from Denver Botanic Gardens' seed bank that researcher Alex Seglias is using to test how Colorado's alpine plants will fare in a changing climate. May 25, 2022.

Sprouting seeds from Denver Botanic Gardens' seed bank that researcher Alex Seglias is using to test how Colorado's alpine plants will fare in a changing climate. May 25, 2022.

KEVIN-lighter

In 2007, the Bureau of Land Management approached the Denver Botanic Gardens with a concern. Sclerocactus glaucus, a small, round cactus that sprouts hot-pink flowers, had been on the endangered species list since 1979. The government needed to make sure the little species didn’t go extinct as oil-and-gas development and rampant plant-poaching threatened its livelihood.

So Michelle DePrenger-Levin, a DBG researcher, set out to find the species and study it for the long term. Every year, she takes a trip across the state to check in on thousands of individual plants that she’s tagged and tracked since her project began. Her work, in addition to a headcount orchestrated by the BLM, found that the spiky globes were doing better than expected.

Sclerocactus glaucus, one of Denver Botanic Gardens researcher Michelle DePrenger-Levin's specialties, pressed and accessioned in the Denver Botanic Gardens' herbarium collection. May 25, 2022.

Sclerocactus glaucus, one of Denver Botanic Gardens researcher Michelle DePrenger-Levin's specialties, pressed and accessioned in the Denver Botanic Gardens' herbarium collection. May 25, 2022.

Thanks to these efforts, the cactus will officially shake its endangered status. But the future holds unprecedented uncertainty for Sclerocactus glaucus and a lot of other Colorado species. Now, DePrenger-Levin and her colleagues are working to get ahead of biggest existential threat facing this state’s flora.

“If things are kind of okay. If we don’t continue to ruin the climate, then maybe it’ll go on fine,” she told us recently as she produced a stack of pressed Sclerocactus glaucus from a research cabinet. “But even in ten years, I think we will pick up on if we start to have catastrophic events.”

In reality, we don’t really know what climate change will mean for Colorado’s plants. We need more science to find out.

Researchers across the world are zeroing in on individual species to figure out what hotter temperatures and more frequent natural disasters will actually do to them. Some may thrive, and bring different complications, like more miserable allergy seasons, with them. Others may not fare so well.

Even when her rare cactus is delisted from U.S. Fish and Wildlife’s endangered species roster, DePrenger-Levin will continue checking in on her longtime friends. The data she collects each year feeds statistical models that helps her make educated guesses on what could come next. But those equations can only go so far.

The longer she conducts her study, the further she can peer into Sclerocactus glaucus’ future. But she can only guess what unprecedented temperatures will mean for it, since her cacti have never experienced the drastic warming experts predict will happen without serious intervention.

“I think they’ll have a nice big boom for a little while,” she said. And then: “I think there’s going to be a threshold when they’re going to peter out.”

Denver Botanic Gardens researcher Michelle DePrenger-Levin dives into the institution's herbarium records, which contains thousands of pressed plants collected around Colorado. May 25, 2022.

Denver Botanic Gardens researcher Michelle DePrenger-Levin dives into the institution's herbarium records, which contains thousands of pressed plants collected around Colorado. May 25, 2022.

And that’s if something else doesn’t get to them first. A plant’s ability to survive in the wild depends on a complex web of factors, including neighboring species’ abilities to survive around it or other plants that could take over its territory. DePrenger-Levin said she’s not even sure what would happen if megafires sweep through the populations she keeps tabs on.

On one hand, she’d rather not see her cacti burn alive. On the other: “From a data side, I would love to have that forced-upon experiment on my species.”

While researchers like DePrenger-Levin are watching things change in real time, others are experimenting to learn more – and planning for a worst-case scenario.

Through a doorway, beyond where Botanic Gardens visitors could wander, researcher Alex Seglias opens an incubator to check in on tiny seeds she’d begun shepherding into sproutlings. The chamber was set to simulate what alpine temperatures could feel like once the planet becomes warmer.

Her project had just begun, so Seglias couldn’t say what the future might hold for the scrubby asters she studies, but experiments like this will give her a real look at how a changed climate would affect them in the wild. She’s also using plexiglass containers to simulate the effects of temperature change on plants growing in the wild.

Seeds from Denver Botanic Gardens' seed bank that researcher Alex Seglias is using to test how Colorado's alpine plants will fare in a changing climate. May 25, 2022.

Seeds from Denver Botanic Gardens' seed bank that researcher Alex Seglias is using to test how Colorado's alpine plants will fare in a changing climate. May 25, 2022.

Seglias specializes in germination, seeds’ transformation into actual plants, and is one of very few scientists in the nation studying how some rare high-altitude Colorado wildflowers, like Townsendia rothrockii, would perform under warmer conditions.

She’s also the steward of DBG’s seed bank program, a collection of envelopes that currently fits inside a single (very cold, -20C) fridge in her lab.

Her asters are not so picky, and she expects they’ll be able to sprout under a range of future conditions. But, since nobody knows for sure, she is helping preserve what she can in case any of Colorado’s rarest species goes extinct.

“People still consider seed banking the best way to conserve these species that are are at risk of climate change. But something that I think about is: We might make this collection and then, ten years later, we want to use these seeds for a reintroduction process. And the climate may be totally different than what it was at the time of collection.”

Denver Botanic Gardens researcher Alex Seglias stands with the institution's seed bank, all of which fits in a fridge in her lab. May 25, 2022.

Denver Botanic Gardens researcher Alex Seglias stands with the institution's seed bank, all of which fits in a fridge in her lab. May 25, 2022.

Reintroduction may only be possible in places where extinct plants were never found.  This raises larger ethical and practical questions that Seglias said researchers and institutions have been talking about for years. If a plant disappears from Colorado’s high country, should it be brought back to life? While that decision may not result in a Jurassic Park-like catastrophe, it’s still tricky.

“There are continuous debates in the ecological world about which species do we focus our concerns on to conserve, or how do we conserve these species in the face of climate change?” she said.

Seeds from Denver Botanic Gardens' seed bank that researcher Alex Seglias is using to test how Colorado's alpine plants will fare in a changing climate. May 25, 2022.

Seeds from Denver Botanic Gardens' seed bank that researcher Alex Seglias is using to test how Colorado's alpine plants will fare in a changing climate. May 25, 2022.

For example, she said a lot of researchers are interested in “assisted migration,” where humans would plant seedlings in northern climates that might resemble places where extinct species once lived. But not everyone is on board for such a drastic measure, fearing unintended consequences could befall an ecosystem that’s not ready for a brand new resident.

“People are coming at it from different perspectives, and there’s not one clear answer. But I think, you know, we can’t just sit back and just wait for nature to take its course,” she told us. “At the rate we’re going, we’re just going to lose a lot of important species.”

The Botanic Gardens’ researchers have a front-row perspective on where Colorado is headed, for better or for worse.

The thought that her seed bank might be needed in the next century doesn’t always sit will with Seglias. It’s a Noah’s Ark she’d rather never meets a flood.

“There are times when, yeah, I do feel that dread weighing down on me,” she said, “like the world is in a terrible place, like we’re at this tipping point where if we keep going at this rate, then there’s no turning back.”

But doom isn’t a good place to let her mind linger, and she feels a sense of empowerment that she’s on the front lines of a larger fight to do something about it.

Denver Botanic Gardens researcher and seed bank steward Alex Seglias. May 25, 2022.

Denver Botanic Gardens researcher and seed bank steward Alex Seglias. May 25, 2022.

“I think to be in this field, you have to at least have some optimism,” she said. “Otherwise, what’s the point, you know?”

It’s helpful that her work is nested in a public institution like DBG, she added. Here, her work won’t fall into an academic black hole and might inspire visitors to care or take action.

“Being at botanic garden really offers that opportunity to get the science out there and distill it in a way where it’s really easy for the public to understand and really make a connection to,” she said.

DBG scientists publish five or six research papers a year, including one a few years ago that used their vast archive of pressed plants to determine the growth cycles of some Colorado flowers moved back an average of one month over 60 years as a result of climate change.

Denver Botanic Gardens researcher Michelle DePrenger-Levin looks out into the institution's cactus plot. May 25, 2022.

Denver Botanic Gardens researcher Michelle DePrenger-Levin looks out into the institution's cactus plot. May 25, 2022.

DePrenger-Levin, on the other hand, says she can’t help but come a different mindset.

“I’ve always been a pessimistic person. But then, it works well because then I’m pleasantly surprised when things aren’t as bad as I think they could be,” she told us.

Even in a time of crisis, the natural world always holds pleasant surprises. Each year, as drought and disaster causes havoc across the state, she finds those little gifts when she heads into the Colorado desert to check on her cacti.

“It looks like it’s gonna be horrible. And then, to see these guys blooming and you know, doing their thing,” she said. “Everything is just growing so well. I’m watching these decade-old patterns happening, but seeing some of these plants rebound in some interesting ways, it’s – I don’t know. I’m hopeful.”

Correction: The language in this story was updated to reflect that Alex Seglias is one of a few scientists working on rare Colorado wildflower germination, that her fridge is really more of a very cold freezer. We also clarified that Michelle DePrenger-Levin’s cactus project began in 2007 amd corrected the term “assisted migration.”

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