By Donnisa Edmonds

Medill Reports

Amid rising global concern about climate change, scientists at the Chicago Botanic Garden are tackling conservation and extinction in a unique way — by seed banking.

The Dixon National Tallgrass Prairie Seed Bank at the Chicago Botanic Garden is one of about 1,700 seed banks across the world busy collecting and storing millions of plant seeds.

“The overall program here is about plant conservation and restoration, so conserving species out in the wild, where they live, and also conserving offsite here in the collections and in our Seed Bank,” said Kayri Havens, Ph.D., a chief scientist at the Garden’s Negaunee Institute for Plant Conservation Science and Action. “And it all starts with seeds. Seeds are a wonderful way to conserve plants for the long term.”

As a result of climate change, habitat destruction, loss of pollinators and other environmental factors, many native plant species are dying globally. A 2019 study in Science Advances reported almost 40% of all native plant species in the world are exceedingly rare and vulnerable to extinction.

Seed banking, the process of storing seeds to preserve genetic diversity, is one way to safeguard against the growing threat of plant extinction. As long as seeds exist, it will be possible to reintroduce plants back into their native habitats.

However, conserving seeds requires a specific process.

Seed banking starts with collection. Havens explained that most collecting at seed banks occurs during the fall, when many plants naturally drop seeds. Collected seeds are brought back to the seed bank and cleaned, which involves separating the seed from the fruit and the rest of the plant. These seeds are later dried at 15% humidity and sealed in airtight foil before being placed in a temperature-controlled vault.

Almost all seeds in the Garden’s Seed Bank are stored at minus 20 degrees Celsius. Havens noted that the vault currently contains 1,800 different plant species. Each of the 1,800 species can have anywhere from 3,000 to 300,000 seeds stored. If the seeds are stored properly, they can last for decades or even centuries.

The Seed Bank focuses primarily on plants native to the tallgrass prairie and is in the process of banking some of the rarest seeds in the Midwest. There is a small percentage of seeds that can’t be frozen, but they can be preserved through other means, such as pollen banking.

However, Havens said that in addition to preserving and storing seeds, much of the work that happens at the Seed Bank is about making sure the seeds don’t stay in the vault forever.

“We want it to be a bank, not a morgue,” Havens said. “We really want to be using those seeds: getting them back out onto the landscape, getting them into collections and making sure they don’t just molder away in there.”

To ensure this, the Seed Bank is involved in a wide variety of land restoration efforts to bring back prairies in Illinois. The bank makes all its seeds available for research and is in the process of making them available to parties selling seeds for restoration efforts.

Ryan Lothian, senior manager of Conservation Impact at the Garden, highlighted the many partnerships through which the Seed Bank is returning seeds to nature. They work with the Chicago Park District to convert lawns to clover or meadows with higher plant diversity and provide seeds for the garden at the Gichigamiin Indigenous Nations Museum.

One of their larger projects is a partnership with the Forest Preserves of Cook County. The Seed Bank is currently working to provide enough seeds to restore 30,000 acres of forest. Through this project, the Seed Bank has been able to merge urban farming efforts with land restoration.

The Garden supports several farms across the city of Chicago known as Windy City Harvest Farms. According to Lothian, while these farms largely focus on growing fruits and vegetables, the Rodeo Farm site has been growing eight varieties of native plants in an area that is too shady to grow crops. The seeds for these native plants were initially collected within the Forest Preserves.

“(The seeds) are grown out there, amplified and then they’re harvesting each year,” Lothian said. “The first year they got eight pounds, the second year it was 50 pounds, so it’s something we’re thinking about expanding — to grow within urban spaces the seeds that we need to restore the Forest Preserves.”

They are also contributing seeds to restoration efforts within the Botanic Garden, allowing researchers at the Seed Bank to troubleshoot some of the potential issues that can arise with reintroducing native plants back into the wild.

Andrea Kramer, Ph.D., is the senior director of restoration at the Negaunee Institute and has been working to reintroduce rare orchids to McDonald Woods.

McDonald Woods is an old woodland within the Botanic Garden that has been undergoing restoration for almost 40 years. Kramer cited recent efforts to reintroduce the purple fringed orchid to the woodlands as an example of some issues that can occur during restoration.

“Deer love to eat orchids, and they love the species that are the most rare usually, and so it’s like a negative feedback loop,” Kramer said.

In addition to direct interference from hungry wildlife, the relationship between plants and other organisms can limit reintroduction. According to Kramer, orchids have close relationships with fungi; they help them get the energy they need to grow, so the right type of fungi needs to be present in the ecosystem for these rare orchids to grow.

The Seed Bank also offers myriad ways for nonscientists to get involved in land restoration, cultivating native plants and even seed preservation.

People can volunteer to collect and clean seeds with the Seed Bank, but it also has online resources on how to preserve seeds at home. Through the Negaunee Institute, the Seed Bank is also involved in  BudBurst, a nationwide program that allows anyone to help track the progress of climate change by reporting on the flowering patterns of local plants in their own backyard or nearby woods.

In the future, the Lothian hopes to publish additional resources through the Seed Bank on how to support native plants through gardening, which is a key thing people can do at home to support seed banking and restoration efforts.

“It’s hard to find things that people can do and feel good about and that actually make a difference,” Lothian said. “Gardening is one of those things, so we want to give people the tools to be able to do that.”

Donnisa Edmonds is a Ph.D. candidate in the Interdepartmental Neuroscience program at Northwestern. You can follow her on X at @donnisa_ and on Bluesky at @donnisa.bsky.social.