GREATER LAKE TAHOE AREA, Calif./Nev. – If you have lived in Tahoe or frequented it for some time, chances are you’ve heard about Tahoe yellow cress or stumbled on beach signs cautioning of the rare and endemic species. But have you heard of the plant called Tahoe draba?

“It hasn’t received as much attention in part,” plant ecologist, Robert Shriver says, “because it just doesn’t have as many direct human impacts as Tahoe yellow cress, which is really impacted by whatever level they’re setting the lake at with the dam at Tahoe City.”

Tahoe draba (Draba asterophora) is another one of Tahoe’s rare endemic plants. “Endemic species in general are cool because,” Shriver says, “these are the species that only live here.”

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Rather than the sandy beaches of its endemic counterpart, Tahoe draba is found in the gravely soil of decomposed granite located in high elevation alpine environments. “And it’s often in the places where the snow sticks around pretty late into the year,” the professor and researcher at the University of Nevada, Reno, explains.

One of his master’s students, Sage Ellis, found herself particularly struck by the resilience of rare plants like the Tahoe draba. “These species often occur in habitats that are pretty inhospitable to most other plants and they just have the right stuff to endure some of these conditions, which,” she says, “I think is super cool to see and observe.”

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It’s one of the reasons why she chose the Tahoe draba for her thesis project. The natural resources and environmental sciences student finds people are often surprised at the size of the plant. “It’s this tiny plant,” she says, raising her hand to demonstrate, “that is usually about this big, the size of a quarter, maybe a little bit bigger.”

“It’s just a cute little guy that is up there.”

But despite the mustard family member’s small size, both teacher and student find the plant plays a significant role in making Tahoe special. “Lake Tahoe is a pretty unique and beautiful place,” Shriver says. “One of the things that makes it unique and beautiful are the things that only live in that area.”

He adds, “preserving what makes the region unique and beautiful, I think is really important.”

The Tahoe Draba is a threatened species in both California and Nevada.

Shriver and Ellis’ fascination for rare plants is partly due to their mystery. The professor explains, it’s always a question of what makes them rare. “Are they rare because they’ve always been rare? Are they rare because something has caused them to decline?”

Both Shriver and Ellis have conducted a three-year monitoring program for the species as a part of Ellis’ master’s program to gain data to one day answer those questions.

A grant through the Lake Tahoe License Plate program provided the funding for the three-year project that started in 2022 and is ending this year. Ellis and Shriver conducted the project by revisiting Tahoe draba populations the USDA Forest Service had previously monitored. It gave the Tahoe draba the first monitoring attention in years.

Over the course of the project, they’ve found in general that Tahoe draba has declined since it was last monitored by the Forest Service around 2015. “Unfortunately,” Shriver says, “we don’t know when exactly that decline occurred.”

Ellis and Shriver have seen populations slowly increase since their monitoring began in 2022, “…but they’re not quite back up to where they were prior to that decline,” Shriver notes.

Draba’s high altitude location doesn’t keep it totally out of reach of human impacts. It’s been found within two major ski areas in the Tahoe Basin with populations on Mount Rose and Heavenly Ski Resort.

Shriver said there has been past evidence that grading ski runs has impacted the plant. However, that doesn’t appear to be the culprit for this decline since the populations in those ski resort locations aren’t doing any worse than others.

“So whatever mitigation, disturbance limitation efforts the ski areas have had,” Shriver says, “do seem to be helping in that regard.”

But the question remains, why the decline? Due to the gaps in monitoring and not knowing exactly when the decline occurred, it’s hard for Shriver and Ellis to say what caused it. The gap years between monitoring presented both wet and drought years. From the limited data available, they’ve found that warm winters and late snowmelt each have negative impacts as well as reduced summer precipitation.

Further answers may take more time since this is the last year of funding for their current project. “It’s a challenge that anyone has to maintain these monitoring programs because they cost money and there’s often a lot of needs for research in other places as well,” Shriver explains.

He hopes to still monitor the populations potentially every couple of years until they receive funding to do another monitoring project. For now, the goal is mitigating avoidable impacts.

“If you’re not actively out looking for these plants, you could pretty easily miss them if you’re not looking at the new spring flowers,” Ellis says.

Populations are often found near hiking trails and one of the main human disturbances to the Tahoe draba is off-trail use. “Especially because they’re so small,” Ellis explains, “I don’t think people realize that they’re trampling them.”

In some regions where they are found, including Heavenly, site managers have placed signs and barriers to help keep people from unintentionally trampling them.

“We can’t necessarily control longer-term climate trends or what the weather is, but we certainly can make things better,” Shriver explains, “by limiting impacts that we have direct control over.”