A rare plant gets help from a biology professor and his students

It’s just a small population of a small plant. But it matters.

That’s why the National Park Service has turned to Associate Professor of Biology Ross McCauley and his students to see what might be the best way to give Astragalus schmolliae the best chance to survive and thrive in its small domain in Mesa Verde National Park.

The rare species of legume is only known to exist on southwestern Colorado’s Chapin Mesa, in remote parts of Mesa Verde National Park and the Ute Mountain Ute Tribal Park. It was first recognized as a unique species in the 1940s and has been monitored by the park since the late 1970s because of its globally rare status.

"Recent trends inferred from the monitoring data are showing a reduction in the number of individuals in individual sites and a general reduction in the size of the total population,” says McCauley. “Some of that seems to be due to the 2002 fire on Chapin Mesa, which affected a large area of the plant’s habitat.”

Immediately following the fire, E. schmolliae appeared to rebound, but it has since continued its mysterious decline. This has prompted the Park Service to consider applying for protection for the plant under the Endangered Species Act.

Part of the process of applying for Endangered Species designation is to collect data about the status of the species. The Park Service has historic demographic data that describe characteristics such as its distribution, population sizes, and reproductive processes, but there is no information about the species’ genetics, says McCauley. So that’s what he and his team aim to find out.

The project is a two-year study to "sample plants across the distribution and then genotype these to understand patterns of genetic diversity," McCauley says. "This will give us insight into how the genetic diversity is distributed across the species, where it's the most diverse, and how that diversity may be related to the structure of the community in different parts of its range. Then we’ll combine that with the park’s demographic data to develop a management plan."

The project’s field and laboratory work involve traveling to the national park, 45 miles west of Durango, and gathering hundreds of small leaf samples in the spring and summer (work that started this summer). Samples are then transported on ice to the laboratory on campus, where they are stored at -80C. Students then will be working with faculty on the DNA extraction and analysis.

“In modern conservation, genetics is a very important aspect,” explains McCauley. “We talk about genetic diversity, and how much a species maintains within its population and how that is distributed. That really helps to address a couple key concerns: How might that species respond to changes in the environment? Does it have low genetic diversity, and thus doesn't have the ability to adapt? Or does it have diversity, and if we manage it properly, we can improve the chances of that population surviving?"

Regardless of the success or failure of these efforts, though, there is a question that lingers: Why should we care about such a rare and remote little plant?

"That's a question we're asked all the time in plant conservation,” McCauley says. “The answer is, because we're trying to preserve all biodiversity. Biodiversity gives you stability in an ecosystem. If you have just one species, you're not very stable, and you're not able to a support a complete functioning ecosystem. So the greater the diversity, the greater stability and resilience to change.”

“You can look at the big species that get all the attention, like elephants and polar bears,” he continues, “but plants are the base of all terrestrial ecosystems. And so what we want to do is preserve as much of the plant diversity that makes up these ecosystems as we can."