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Ferns of Rocky Mountain National Park

Botanist Scott Smith specializes in ferns, orchids and cactus, but today at the Rocky Mountain National Park BioBlitz he was looking for ferns. At something like 9,500 feet above sea level, in the park’s subalpine zone, he showed visitors how to find two species of an ancient plant invisible to all but expert eyes. The expedition formed part of the BioBlitz organized by the National Park Service and the National Geographic Society to identify in 24 hours as many species as possible within Colorado’s Rocky Mountain National Park. Thousands of students and other members of the public were led by some 150 scientists into the different environments of the park to help spot and catalog species.

National Park Service map indicates the location of Hidden Valley in the Rocky Mountain National Park. Photo of NPS map by David Braun/NGS.

I joined the fern inventory team that boarded a school bus for a midday excursion to the subalpine region of Rocky Mountain. The park ranger on board recounted some of the history of the park and told us what was so special about the plants and animals living in the subalpine ecosystem, which lies between 9,000 and 11,400 feet. Our destination was Hidden Valley, site of a former ski resort slowly being restored to wilderness.

Smith led our small team up a former ski run. Around us towered the peaks of the Rocky Mountain tundra, a forbidding treeless place that even in late August has patches of snow. But where we were was pleasantly warm, although it was a little difficult to breathe evenly as we climbed the slope; subalpine air, we were told, contains only 70 percent of the oxygen found at sea level. But walking up the steep slope also gave us the impression that we were leaning toward the ground, making it easier to scan the small plants in front of us.

Our quest was the subalpine ferns of Rocky Mountain National Park. Smith briefed us before our climb that he had already scouted the area and found only small patches of tiny ferns that were not in very good condition because they were at the end of their season. We waded through a meadow of wild flowers, alive with bees, dragonflies, and grasshoppers snapping their wings about our heads. Stellar’s jays flitted through trees near us. “Is this a fern,” asked one of our “citizen scientists,” pointing enthusiastically in the direction of a cluster of grasses and other plants. It was a Gentian. “I’ll let you know when we are near the ferns and you can show me where they are,” Smith said.

Botanist Scott Smith (foreground) shows BioBlitz participants where ferns are growing around the remnants of infrastructure built for a commercial ski run decades ago. The National Park Service dismantled the structures and is in the process of restoring the area to wilderness. Ferns were among the first plant settlers in the distressed landscape, taking advantage of the lack of competition from other plants to establish themselves in nooks and crannies of eroding concrete foundations. Photo by David Braun/NGS.

 

After a few more false alarms and an exciting discovery of scat containing a voluminous pile of digested remnants of a very hairy animal, Smith announced we had reached a spot where ferns were all about us. In the miniature forest around my ankles I could see nothing that looked like what I know to be a fern. “Remind us, what makes a fern a fern,” I asked. “Spores,” Smith said. Ferns have neither seeds nor flowers. They propagate by means of spores, reproductive cells they shed for transport by wind or water to just the right conditions to germinate and thrive.

Fern leaves come in a variety of shapes and sizes, not only the familiar fronds of the more popular ornamental plants that I was expecting to find. It was tough to know what I should look for. Smith said botanists may also be challenged to find some tiny species, so they look for clues. A more showy plant, such as a strawberry, could indicate the presence of obscure fern species known to grow in the same conditions. Shade or sunny location and even recent environment distress, such as a heavily used ski slope, could be a clue for ferns that would have an edge over other plants in such places. But not even the clues could help me see ferns apparently hiding in plain sight.

We were looking for this:

 

Botrychium, also known as Moonwort, a fern found in the subalpine zone of Rocky Mountain National Park. Photo by David Braun/NGS.

 

Smith showed us Botrychium, also known as Moonwort because of its lunar-shape leaves, a relatively common fern in the Rocky Mountain National Park. Found in the subalpine ecosystem all over the world, it is difficult to see in the tangle of strawberries and lookalike plants. Moonwort has survived for millions of years, even though its spores must find a water source, the mycorrhizal fungus beneath the soil which it needs to help feed itself, and a crack in the ground to provide the darkness required to germinate.

Common Moonwort illustration courtesy of USDA.

Moonwort may not be an extravagant fern like those I associate with tropical jungles, or even my Northern Virginia backyard, where the impressively large native Ostrich Fern is asserting itself aggressively. But it has a fascinating story and could be a poster species for adaptation and persistence of life.

The hunt for this tiny obscure fern on the high slopes of the Rockies was the highlight of  my rewarding expedition into Hidden Valley’s wildflower meadows. I find that the real value of a BioBlitz is the discovery of a species new to me.

More about Moonwort (USDA)