‘The canary in the coalmine’: How does a flower ring an alarm bell? It begins to disappear

ST. LOUIS, Mo. (First Alert 4) - Wetlands and floodplains have been rapidly depleting across the United States, and many of the plants that once thrived in the turbulent environment of floodplains are now facing a harsher reality.

In hopes of learning about the effects of habitat loss on different plants, the Decurrent False Aster is one of the six plants studied by the Missouri Botanical Garden Center (MoBOT) for Plant Conservation’s National Collection of Endangered Plants.

The Decurrent False Aster only grows in floodplains, and its endangerment is from humans, making it a clear choice for researchers.

“It’s kind of a canary in the coal mine in terms of habitat destruction,” said Christy Edwards, a scientist with MoBOT who works with the Seed Bank, which holds the seeds of the plant species being studied.

“I think the idea is, is that with all of the species that we have on the planet, they all have different connections to different other species, you know, pollinators, seed dispersers, and all of those connections are important,” said Edwards. “If you lose one member of the community, it causes the system overall to become more fragile. And so, as you lose species, it becomes more and more fragile.”

MoBOT and the Seed Bank have hundreds of samples of seeds from each plant in the study. Each seed is labeled and assessed for variables beyond the species type and serves as a way to study the best growing practices for each plant. Labels include information such as where the plant was harvested from, the date it was harvested, and several other technical markers used to study the plant’s genetics.

“Our project on (Decurrent False Aster) is part of the larger project looking at essentially the best way to conserve variation in endangered species,” said Edwards. “What we’re trying to do is look at all these different forms of variation… and then use that data to do the best job of conserving that variation in the most efficient way possible.”

The Decurrent False Aster grows naturally from Missouri through Illinois, which leads to studying the flower in different growing climates. However, it’s also noteworthy as there are multiple known growing areas in Illinois, and only one area consistently blooms in Missouri due to wetland disruptions.

“Because of all the changes that we’ve made in wetland habitats, it’s caused changes in flood regime, and that’s caused issues with (the Decurrent False Aster). So, it’s caused losses in habitat,” said Edwards. “It’s a species where we can do something to try and conserve and do a good job of doing it, because it’s not endangered just because it’s rare.”

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In January 2025, dozens of pots of Decurrent False Aster were lined up within MoBOT’s Hardy Plant Nursery. The plants were just beginning to peek over the edge of their pots.

“When they are little, they just form a small rosette, and then they get to be, you know, four or five feet tall,” said Edwards. “So, several technicians that were measuring them, and they’re like, ‘we can’t actually measure them because they’re so tall.’”

The flower reaches its peak height during blooms, typically in late summer from July through October.

The plant is known for its need for “disturbance” and flooding to eliminate competing vegetation and provide high light and moist soil for the seeds. Several research papers have noted that the flower responded well to the Great Flood of ’93, as much of the area it grows in was covered by floodwater for up to 10 weeks.

The plants are considered “hardy” and able to grow and thrive in harsher climates.

Edwards notes that since the plant only grows when there have been soil disruptions, it does not grow yearly. However, this does not affect the population of the Decurrent False Aster, and it is large-scale changes that have impacted the plant.

“If you clear it and it’s a historical population, then it’ll pop back up. And so, it just depends on like the different environments and whether there’s like a kind of a disturbance event that will clear the canopy for that species,” said Edwards in reference to the flower. “There’s probably only a few ways which the population could be dead… like, physical structure, right? So, if you put concrete along the sides of riverbanks, or if you like, chain, ditch and channel like a floodplain, then that would cause the population to just go away.”

Such structures were brought about in the 20th century, in part by agricultural development and in part by the United States Army Corps of Engineers. The US Army Corps began to implement locks, dams, and other flood mitigation strategies to help alleviate destruction to housing and farmland, many of which are still in use as of 2025.

“It’s complicated, and how you’re actually supposed to restore that because it means you have to try to change like flows in the river,” said Edwards. “So, trying to restore those kinds of natural flood cycles would be a really important tool for conserving this species and restoring its habitat.”