I ran into an old friend five thousand miles from home last weekend. But the story actually starts several years ago when I first began exploring the Rocky Mountains.
Near my research sites there was one peak visible to the north, higher than all the others: the Treasure Mountain massif. And I had never climbed it. Below is a view of the peak covered in snow in 2013, taken from a different mountain.
This year I finally was able to satisfy my curiosity and climb to the top of Treasure Mountain. It was well worth it, and not just for the views.
Near the summit I found a population of one of my favorite species, moss campion (Silene acaulis, in Caryophyllaceae). It grows in a low, cushion-like form, with small sharp green leaves. For most of the year it is under snow, but for the summer it puts out a beautiful display of five-petaled pink flowers. Observing it from ground level is a worthwhile exercise. Of all the plants I have met, only jasmine and orange flowers have a richer scent. It is a pleasure to find this species, because it is truly restricted to the high alpine zone and often does not appear on many high peaks.
So imagine my surprise when I found this familiar friend five thousand miles away on an unfamiliar mountain. I am in Norway this month on research collaborations at NTNU in Trondheim, and took last weekend to climb Blåhøa, the highest peak in Trollheimen.
The weather for the ascent was poor, and the views from the summit cliffs were nonexistent.
As I navigated my way back down in the winds and mist, I noticed the same moss campion growing out of the rocks!
A familiar species in a foreign land is always a comfort. In this case, Silene acaulis has a holarctic distribution, meaning it can be found not only in the Rocky Mountains but also in the tundra of Svalbard, the peaks of Fennoscandia, and the windswept plains of Siberia. The interesting thing is that the species occurs at very different elevations in each part of its range. My photo in Colorado was taken at 13,500′ elevation – and my photo in Norway was taken at only 5,300′ elevation. The alpine zone starts at very different elevations in different parts of the world, generally becoming much lower at higher latitudes where growing seasons are shorter.
The other reason I was glad to see this species is that it is a classic example of how microclimate construction leads to species interactions. As a low and dark-colored plant, the moss campion escapes high winds and traps heat at the surface, enabling it to be much warmer than surrounding plants or bare rock (Körner 1999) – a notable benefit for growth in cold and short summers. And these warmer microclimates in turn facilitate the growth of nearby plants (Molenda 2012). I like to imagine Silene acaulis as a friendly ecosystem engineer.
I’ve been thinking a lot about microclimate recently, and this species provides much inspiration for my work. I am sure there is far more we don’t understand about the slow and quiet life of this foundation species. I will have to spend more time with it, wherever I may find it.