Archives For conservation genetics

Rooting for Native Plants

Undercover Science

Julianne Beck —  October 25, 2016 — Leave a comment

Competition is heating up in the western United States. Invasive and native plants are racing to claim available land and resources. Alicia Foxx, who studies the interplay of roots of native and invasive plants, is glued to the action. The results of this contest, says the plant biology and conservation doctoral student at the Chicago Botanic Garden and Northwestern University, could be difficult to reverse.  

Cheatgrass, which is an aggressive, invasive plant with a dense root system, is in the lead and spreading quickly across the west. Native plants are falling in its wake—especially when it comes to their delicate seedlings that lead to new generations.

Foxx is one of the scientists working to give native plants a leg (or root) up. She hypothesizes that a carefully assembled team of native plant seedlings with just the right root traits may be able to work together to outpace their competition.

PHOTO: Alicia Foxx (left) participates in seed collection in Southeastern Utah.

Alicia Foxx (left) participates in seed collection in southeastern Utah.

“We often evaluate plants for the way they look above ground, but I think we have to look below ground as well,” she said. Foxx’s master thesis focused on a native grass known as squirreltail, and her hypothesis addressed the idea that the more robust the root system was in a native grass, the better it was at competing with cheatgrass. Now, “I’m looking more at how native plants behave in a community, as opposed to evaluating them one by one… How they interact with one another and how that might influence their performance or establishment in the Colorado plateau.”

In the desert climate, human-related disturbances such as mining, gas exploration, livestock trampling, or unnaturally frequent fires have killed off native plants and left barren patches of land behind that are susceptible to the arrival of cheatgrass.

PHOTO: Seedlings in the growth chamber.

Seedlings in the growth chamber

“Some of our activities are exacerbating the conditions [that are favorable for invasive plants]. We need to make sure that we have forage for the wildlife and the plants themselves, because they are important to us for different reasons, including the prevention of mudslides,” she said. “We are definitely confronted with a changing climate and it would be really difficult for us to reverse any damage we have caused, so we’re trying to shift the plant community so it can be here in 50 years.”

Garden conservation scientist Andrea Kramer, Ph.D. advises Foxx, and her mentorship has allowed Foxx to see how science theories created in a laboratory become real-life solutions in the field. “I think I’m very fortunate to work with Andrea, who works very closely with the Bureau of Land Management…it’s really nice to see that this gets replicated out in the world,” said Foxx. Seeds from their joint collecting trip in 2012 have been added to the Garden’s Dixon National Tallgrass Prairie Seed Bank.

Alicia Foxx loves to walk through the English Walled Garden when she steps away from her work.

In a way, Foxx is also learning from the invasive plants themselves. To develop her hypothesis, she considered the qualities of the invasive plants; those that succeeded had roots that are highly competitive for resources. After securing seeds from multiple sources, she is now working in the Garden’s greenhouse and the Population Biology Laboratory to grow native plants that may be up to the challenge. She is growing the seedlings in three different categories: a single plant, a group of the same species together, and a group of species that look different (such as a grass and a wildflower). In total, there will be 600 tubes holding plants. She will then evaluate their ability to establish themselves in a location and to survive over time.

PHOTO: Seedlings: on the right is a sunflower (Helianthus annuus) next to a native grass (Pascopyrum smithii).

On the right: a sunflower seedling (Helianthus annuus) next to a native grass (Pascopyrum smithii)

There has been very little research on plant roots, but Foxx said the traits of roots, such as how fibrous they are, their length, or the number of hair-like branches they form, tell us a lot about how they function.

“I’m hoping that looking at some of these root traits and looking at how these plants interact with one another will reveal something new or solidify some of the theories,” said Foxx.

She aims to have what she learns about the ecology of roots benefit restorations in the western United States. It is possible that her findings will shape thoughts in other regions as well, such as the prairies of the Midwest. Future research using the seeds Foxx collected could contribute to the National Seed Strategy for Rehabilitation and Restoration, of which the Garden is a key resource for research and seeds for future restoration needs.

The Chicago native has come a long way since she first discovered her love of botany during high school. After completing her research and her Ph.D., she hopes to nurture future scientists and citizen scientists through her ongoing work, and help them make the connections that can lead to a love of plants.


©2016 Chicago Botanic Garden and my.chicagobotanic.org

Between a Rock and a Future

Undercover Science

Julianne Beck —  January 10, 2015 — Leave a comment

A pretty little iris growing in the mountainous rocky outcrops of Jerusalem is the focus of a research collaboration stretching over 6,000 miles.

Scientists at the Chicago Botanic Garden and Jerusalem Botanical Gardens have combined their strengths to study the natural population structure, or remaining genetic diversity, of the rare Iris vartanii. What they have discovered may save the species, and others like it, into the future.

The finicky wildflower exists in just 66 locations in Israel’s Mediterranean ecosystem—a dangerously low number. New road construction, urban expansion, and even afforestation in the area have reduced the availability of its natural habitat, fueling the crisis. For a plant that is endemic to, or only lives in, one narrow region, that spells trouble.

PHOTO: Iris vartanii ©Dr. Ori Fragman-Sapir

Iris vartanii Photo ©Dr. Ori Fragman-Sapir

“Whenever you have a rare plant, you always have concern that as diversity starts to go down, the plant becomes more and more endangered,” explained Garden volunteer and molecular biologist Eileen Sirkin, Ph.D. “The idea of diversity is that maybe one plant is more drought tolerant, another is more flood tolerant, and another is more wind tolerant, for example, so no matter what the conditions, there will be some survivors. As you narrow that, you are more and more in danger of losing that species.”

Do the existing plants contain adequate genetic diversity? And to sustain the species, how many plants are enough? These are the central questions.

Gaining a Foothold

The scientific partnership between the two gardens was forged when Jerusalem Botanical Gardens’ Head Scientist Ori Fragman-Sapir, Ph.D., who has monitored the species and studied its demography in the field, visited the Chicago Botanic Garden and met with Chief Scientist Greg Mueller, Ph.D. The two quickly saw an opportunity to combine Dr. Fragman-Sapir’s research with the genetic capabilities of the Garden to answer those critical questions.

“Conservation genetics is one of the core strengths of our science program,” said Dr. Mueller.  “There are few other botanical institutions that have this expertise, especially internationally, so we are happy to collaborate on interesting and important plant conservation projects like this one.”

“Conservation genetics is one of the core strengths of our science program,” said Dr. Mueller. “There are few other botanical institutions that have this expertise, especially internationally, so we are happy to collaborate on interesting and important plant conservation projects like this one.”

It wasn’t long before Fragman-Sapir began shipping leaf samples to the Garden’s molecular ecologist, Jeremie Fant, Ph.D. Together with his dedicated volunteer Dr. Sirkin, Dr. Fant set to work extracting data from the samples and documenting DNA fingerprints for each plant. Once they had a large enough data set, they compared and contrasted the findings—looking for similarities and differences among the plants’ genetic compositions.

Gaining Altitude

To give scientists a point of comparison, Fragman-Sapir shared tissue samples from five populations (geographically separated clusters of plants) of a more commonly occurring related species, Iris histrio. By also documenting the DNA fingerprints of those plants, which grow in the surrounding area, but unlike Iris vartanii are not rare, Fant was able to determine how much diversity is needed to sustain the species.

PHOTO: Volunteer Dr. Eileen Sirkin

Dr. Eileen Sirkin volunteers in the laboratory.

Although the study subject is far away from the Garden, its challenges hit close to home. In 2013, Fant and Sirkin published findings from a similar study on a rare plant found at Illinois State Beach Park, Cirsium pitcheri. For that initiative, they examined the DNA of plants from a restored site at the beach and compared them to the DNA of naturally occurring plants across the range, measuring diversity.

“We’re always working with rare and endangered species, and we collaborate with different people around the world to answer those questions,” explained Sirkin.

The Summit

After completing a statistical analysis of Iris vartanii’s DNA fingerprints, Fant made several encouraging conclusions but also issued an alert for continued attention.

The rare species’ genetic diversity was similar to that of Iris histrio. “This does tell us that genetic diversity in Iris vartanii is not likely an issue,” said Fant, who was not surprised by the conclusion. “Genetic diversity of any population is determined by the origins of the species, the age of the population, and proximity to the site of origin,” he explained. “As both species likely arose locally [from Jerusalem northward to the Galilee and further on] and have been around for a very long time, they possess similar levels of genetic diversity.”

PHOTO: Dr. Jeremie Fant.

Conservation scientist Dr. Jeremie Fant

Especially encouraging was that each Iris vartanii population had significant differences in their genes, likely a result of their longtime separation. The findings highlight that it is all the more valuable to conserve each population for their potential to contribute unique genes to future plants, according to Fant.

Although many populations showed high diversity and low inbreeding, which is preferred, others showed the reverse, increasing their potential risk of extinction. The latter group, explained Fant, may benefit from extra special monitoring and care.

To conserve the existing populations, attention will need to be given to their surrounding natural areas, explained Sirkin. “If you find a species that people like and you study it and say we need to do all these things to save it, you are not just saving one plant, you are saving an ecosystem, including all the other plants, insects, other invertebrates, lizards, birds, and whatever else is involved in that ecosystem,” she said.

The findings and recommendations give land managers a clear direction for their conservation efforts, all because of one eye-catching plant that told the story of many.


©2015 Chicago Botanic Garden and my.chicagobotanic.org