Nahanni Aster

Dotted across various spots where tufa and thermal springs converge in Nahanni National Park Reserve is the endemic Nahanni Aster.

The small, white flowering plant’s only known locations are within the boundaries of the park, meaning it is endemic to Nahanni.

Within ecosystems, everything relies on each other, like the tufa (a calcite formation) needs spring water to form, the Nahanni Aster needs both the tufa and thermal spring waters to survive and thrive.

Because of its rarity, the Nahanni Aster is listed as “Special Concern” under the Species at Risk Act and Parks Canada works hard to monitor and protect the plant.

First discovered at a few sites in the 1970s, only two dedicated surveys had ever been done. The most recent? Back in 2012.

That left quite a few unknowns about the species - how are the populations doing since the last survey? What does Nahanni Aster like or not like as a habitat? Are there any other undiscovered populations?

So in summer 2019, four Parks Canada staff set out to explore remote and incredible springs where Nahanni Aster is found to better understand its biology and distribution. They aimed to not only set up a monitoring program at the known sites, but also visit other, previously unexplored thermal springs in search of potential new Nahanni Aster populations.

Adventure along with us as we take you back to that summer in our weekly serial series, “The (Not-So-Secret) Life of the Nahanni Aster Seekers.” We’ll be posting on Parks Canada NWT’s Facebook page for the next eight weeks, and you can scroll further on this page to read the stories as they are published.

The (Not-So-Secret) Life of the Nahanni Aster Seekers

In this weekly serial series, the seekers will be sharing stories with you over the next eight weeks. We’ll explain what exactly we did in summer 2019, all the exciting things we saw along the way, and most importantly, what we found!

• Serial 1 – The One Where We Planned and Prepared

  The Nahanni Aster has only been known to science since 1975, when botanists Scotter and Cody found it at three springs within Nahanni National Park Reserve. Two more surveys, in 2003 and 2012, found populations at three more sites; but the different survey goals and methods make them hard to compare.

  We wanted specifics:

  • How many Nahanni Asters are there?
  • How much of each spring did they cover?
  • What might be affecting where they grow?
  • What do they like (or not like) as a habitat?

  We wanted to know these things and more so we can plan and better manage conservation efforts, but we also needed the specifics so we could get accurate data for future surveys. Having the specifics allows us to see how things are changing over time, which is critical for the future.

  Since Nahanni Aster hadn’t been monitored before, our first step was to research how other people monitor rare plants, and what kinds of information they collected. That helped us to develop a brand new trip plan, survey protocol and data sheets.

  There was only about four weeks to prepare during the middle of an already busy field season, so we soaked up as much knowledge as we could.

  We reviewed the previous survey reports to learn as much as we could about the plant and the unique habitat in which it grows. That meant studying photographs, and field guides of Nahanni Aster and other similar species so we could identify the plant in the field. We also looked at historical records of springs from previous geological surveys to map out springs with potential habitat for the species.

  Finally, we assembled our camping, safety, and specialized science gear, making sure to double-check everything. There’s no turning back once the helicopter takes off!

• Serial 2 – The One Where We Mapped Very Carefully

  There were no previous records of where the Nahanni Aster grows at each of the springs, so our first task once on the ground was to actually find the plants.

  Can you imagine our excitement the very first time we saw a live Nahanni Aster plant? We were SO excited – very few people get that chance!

  Nahanni Asters are quite small, and when they’re not flowering, they’re hard to spot! We spent at least three hours looking for them at each site. We walked kilometres back and forth across each spring, being extremely careful not to damage the fragile tufa or trample the plants. We even did these surveys barefoot at some sites in order to minimize the impacts to the sites!

  While each spring has to have the right habitat conditions for Nahanni Aster, they’re still all very different—we waded through thigh-deep channels at some sites, nearly got trapped in mud at others, and made an offering of tobacco at the Gahnįhthah Mįe tufa mound, which is a sacred and spiritual place to the Dene.

  As we walked, we mapped the locations of the plants using handheld GPS units, site photos, and notebooks.

  Later, this helped us to calculate the “area of occupation” to include in the Management Plan for the Nahanni Aster in Canada

  If this project excites you as much as it excites us – please submit your comments on the Management Plan by July 21st (that’s NEXT WEEK!) here: https://bit.ly/3epXzEi

• Serial 3 – The One Where We Started Collecting Data

  

  Now that we knew where the plants were at each spring, we could take a closer look at the growing conditions.

  We used a 1 x 1 meter grid to lay out plots – this helps us establish a “control” zone. We did 3 to 4 randomly selected plot counts across each site. Within the grids, we counted the number of Nahanni Aster stems and whether they were flowering or had seeds. This allowed us to get an estimate of the density of Nahanni Aster across the site.

  If there was deep enough water nearby, we used a sonde, a piece of water quality monitoring equipment, to measure pH levels, dissolved oxygen, temperature and conductivity. These factors can affect plant growth.

  

  Like researchers before us, we noticed that Nahanni Asters were more common, grew more densely, and were flowering more near the edges of the springs. But, we also found small, vegetative (leaf-only) plants in areas with old, dry tufa.

  These differences in the type of plant growth may provide insight into what environmental factors create ideal growing conditions for the species, or whether the separate populations have evolved over time so that the plants at each spring now look a little different. We carefully preserved a few samples from each location in a plant press, for further research, along with some of the surrounding species growing near Nahanni Aster.

• Serial 4 – The One Where We Expanded Our Search

  Now that we were familiar with Nahanni Asters from the known sites, we could explore some possible new locations—three springs that had similar water quality characteristics to the known sites, but that hadn’t been visited in previous surveys.

  Using the same methods as the 2012 survey, we flew over each possible spring to see if there was tufa or other suitable habitat for Nahanni Aster. We knew from a glance that the first site was no good, because from the air we could see that the spring was almost dry, there was no tufa around and there wasn’t really any vegetation or mossy substrate.

  The second spring, though, had some mossy meadows and calcium deposits in the soil that were very promising.

  After landing, we quickly found other species of asters (Symphyotrichum boreale) growing along the edges of the forest.

  Then… one of our technicians, Sheyanne, spotted some 2-inch-high plants with narrow, purple-green leaves…it looked like Nahanni Aster! A little more searching turned up a second patch, both of which we carefully mapped before counting stems and collecting some samples. These plants looked slightly different than the Nahanni Asters at other sites, and weren’t flowering, so we were not 100% sure that is what they were. We would have to consult the experts! Still, excitement permeated our team as we made our way back home—we might have found a new population!

  What a way to end our trip!

• Serial 5 – The One Where We… May Have Found a New Population?

  

  It was thrilling to discover what seemed to be Nahanni Aster at a new site on the final day of our trip! But could it be true?

  Had we really found a seventh Nahanni Aster site?

  We couldn’t be certain—not without sending photos of the spring and plant specimens to the world expert on this species, Dr. John Semple, to verify our identification.

  Where we found the plant was kind of a giveaway that it was a Nahanni Aster, but identification can get quite specific and things like leaf width, diameter of the bottom of the plant’s stem and the number of flowering heads can help to tell the Nahanni Aster apart from other closely related species. So, Dr. Semple compared our specimens to known Nahanni Asters to verify all of those factors.

  Thankfully, he quickly confirmed our hopes—there was a new, albeit small, population at Persistent Spring!

  Since Nahanni Aster is found in so few locations, any additional populations can help buffer the species from random destructive events like landslides.

  And there are still more thermal springs that the Nahanni Aster Seekers haven’t made it to, so maybe there are more populations out there!

• Serial 6 – The One Where We Prepare For The Future

  So, we’d found a seventh (!!) Nahanni Aster population, but the adventure doesn’t stop there.

  Because we knew for sure it was a new population now, there was a lot of work to do. We had to gather all of the data, information and plant specimens from the entire summer in one place so we could start to organize and analyze it.

  With such an exciting find, it’s important to share our newly-gained knowledge. We sent a few of the photos and mounted specimens to the Canadian Museum of Nature to preserve for all Canadians.

  We also carefully entered all the plot and GPS data we’d recorded, and cleaned it up so we could see what it told us about the plants and their habitat. Mel, our GIS technician, mapped the data over satellite imagery so we could easily see the plants distribution at each site.

  Once we had all of that organized, we updated our abundance and area occupied estimates for the Management Plan for the Nahanni Aster in Canada, which is now closed for public comments and in the process of being finalized! Thanks for your help with that.

  Nahanni Aster reproduces from rhizomes (long, shallow roots) that produce clones of the adult plant. This makes it hard to count “individuals” when estimating abundance; but our new plot count methods established a more consistent process for future monitoring.

  With all the data lined up next to each other, we found that there is a lot of variability in what this rare plant likes in terms of habitat. Even within the individual sites, we noticed differences and particularly at larger springs, where there’s both flowing water and old, dry tufa terraces.

  We did find that Nahanni Aster plants were denser, taller, and more likely to be flowering in areas closer to deeper water and with warmer air temperatures.

  Ongoing monitoring will help us assess some of the habitat requirements and changes to Nahanni Aster populations. The most exciting part of all our findings?

  There’s still a lot to uncover about this unique plant, and we hope to learn from and work with Indigenous knowledge holders and researchers over the five-year timeline of the Management Plan for the Nahanni Aster in Canada.

• Serial 7 – The One Where We Ask… What’s Next?

  Judging from the data we collected on our 2019 trip—not to mention the new site we found at Persistent Spring!—the Nahanni Aster is doing OK right now. But it’s only found in seven locations, so environmental changes like landslides, invasive species or climate change could harm the plants or their habitat, and quickly threaten the species.

  That’s why the Nahanni Aster is listed as “Special Concern” under the Species at Risk Act.

  Parks Canada will continue to protect the Nahanni Aster under the Management Plan for the Nahanni Aster in Canada, with the goal to protect and maintain the distribution and abundance of the Nahanni Aster population, while improving our understanding of the species ecological role and requirements, and promoting awareness of the species, possible threats, and research opportunities.

  If you inputted your comments into the Management Plan for the Nahanni Aster in Canada before the public commentary period closed on July 21, thank you so much for your contribution.

  We’ll be working over the next few months to implement comments into the plan and it will be released in its final form soon.