Arctic Wonders: Tiny Plants of the Tundra and How They Survive

The world of the northernmost plants is obviously a tough one, but it also has features you may not have considered. For example, Arctic ecosystems are the youngest on earth—only about ten to twelve thousand years old, which is much younger than Homo sapiens! Most land life in the Arctic was eliminated during the last glaciation, so current plant communities have only been able to establish themselves since the big melt.

Living systems in the Arctic are simpler than more temperate ones. As you travel from the equator to the poles, biological diversity diminishes. Generally, there are fewer species in the North but large numbers of them.

“Arctic ecosystems have the same elegant … complexities, the same wild grace, as tropical ecosystems; there are simply fewer moving parts—and on the flat, open tundra the parts are much more visible, accessible, and countable.” —Barry Lopez, "Arctic Dreams"

In response to large-scale change like global warming, northern ecosystems lack the resilience of tropical systems. Besides, in the North, severe disturbances are more common and recovery times are more prolonged. For example, in the fall of 1973 and again in 2003, a rainstorm created a thick layer of ground ice that the muskox could not penetrate to access their botanical food sources. Tens of thousands of muskoxen died.

Not Just Cold

The Arctic is also a dry desert. Precipitation is scant and liquid water is only in the top few inches of soil. Because of the cold, evaporation is very slow. Sometimes moisture at the surface seems abundant, but that is only because it doesn't disappear and simply refreezes every winter.

Not Enough Dirt

Soil development is slow to nonexistent in the Arctic. Dead plant parts can last for years. Soil is thin, acidic, poorly drained and aerated, and lacks nitrogen and phosphorous. There are some spots of higher fertility, such as around boulders or knolls that are slightly raised above the rest of the tundra. Here, snowy owls, gyrfalcons, and jaegers perch to scan their surroundings and their droppings create little oases for plant life—relatively speaking, that is.

A Short Growing Season

In a year, all areas of the earth receive about the same number of hours of daylight: half the year. But in the Arctic, it comes all at once during the summer. Each day does not begin anew with first light. However, the sun shines at a low angle of incidence and therefore packs less of a punch than it does at lower latitudes. With a short growing season in the North, the life cycles of both plants and animals must be finely tuned to take advantage of conditions when they are at their best.

So, how do Arctic plants cope? Let's look at eight common adaptations.

1. Stay low

Summer air temperature can be eight to nine degrees Celsius warmer at ground level compared to just thirty centimetres above it, due to the effects of the cooling wind and solar radiation. Therefore, Arctic plants grow low to take advantage of the warmer temperatures and more gentle wind. Staying low also helps keep the precious growing tips beneath the erosive effect of the fiercest winter winds, which are often laden with cutting ice crystals.

2. Make a Cushion

Growing as a tussock or cushion, the way moss campion does, adds other benefits. A tussock can trap warmth, raising the temperature inside the plant by several degrees above that of the outside air. Dead leaves do not drop off, but rather stay in place, thus adding to the mass of the plant. The tussock also catches blowing dust to add nutrients and matter to its own little patch of soil. In the case of moss campion, the cushion also has a very deep tap root that helps anchor it against frost heaving.

3. Be Ready

Many Arctic plants are evergreens, so that as soon as the light returns, growth can begin anew. Even those flowering plants that are not evergreen grow their flower buds in late summer and then overwinter in that state, so they are ready to go as soon as conditions are right the following season.

4. Track the sun

Some flowers, such as Arctic poppies and mountain avens, work like satellite dishes following the sun, much the way sunflowers do further south. This maximizes heat collection for their reproductive process.

5. Make a Greenhouse

Willows and mountain avens are known for their puffy seed pods, similar to those of the common dandelion. These gossamer enclosures work like little greenhouses to concentrate the sunlight for the maturing seeds. Then, when the time is right and the seeds are ready for dispersal, winds can lift them like tiny parachutes and spread them to new ground.

6. Put on a Sweater

Many plants of the Arctic, like the woolly lousewort, have a furry covering that works just like a sweater to capture warmth and hold it close to the plant. It also serves to net moisture when it is available and to prevent dehydration.

7. Use the Wind

The seed pods of a number of ground-hugging plants, like prickly saxifrage for example, have long stems that seem to defy the benefits of staying low. This is to help with seed dispersal. With their seed pods poking up above the hard-packed snow, they vibrate in the fierce winter winds and release their seeds.

The wind then blows them across the landscape, and even hundreds of kilometres across the frozen sea, until they reach some obstruction and come to rest at its base. If the obstruction is on the sea ice, those seeds will be lost. But if the seeds are on land when the snow melts, they can find themselves in a band of relative fertility, since the winds have been blowing seeds and dust to that spot for thousands of years.

8. Be Tasty

Berry plants, such as blueberry, mountain cranberry, and crowberry have a different adaptation for seed dispersal. By enclosing their seeds in juicy, sweet globes, they make themselves appetizing for voles, lemmings, foxes, bears, ptarmigan, and other creatures. After being eaten, many seeds are not digested and are deposited in the excrement some distance away from the parent plant.

Where are the trees?

There’s a saying in the North: “If you get lost in the woods, stand up.” Trees, like willow and birch, do grow in the Arctic, but they grow more horizontal than vertical and benefit from the same ground-hugging posture of other Arctic plants.

However, contrary to what you might think, the driving factor behind this is not the extreme winter cold—in fact, the coldest temperatures occur in forested regions further south. It is not permafrost, nor strong winds, nor lack of light (although all of these are contributors).

The primary factors preventing vertical tree growth are the lack of summer warmth and the short growing season. All resources must be devoted to developing leaves, roots, flowers, and seeds. There is little left over to produce wood, which is what allows trees to stand upright.

The Challenge of Reproduction

We are accustomed to thinking of bees and butterflies as the primary pollinators of flowers, but they are scarce in the Arctic. Small flies perform that role instead. Since the season is so short, plants must produce their flowers at exactly the right time when the flies are present, which is often a period as short as three weeks. This means that there is much competition between flowering plants to lure pollinating insects. Studies in Greenland show that mountain avens are the clear winners in the contest for pollinators.

Many flowering plants are not exclusively dependent on sexual reproduction through pollination and seed production. Rather, they multiply asexually through bulbils (little self-contained plant offspring) and rhizomes (underground shoots that send up new above-ground stems a small distance away from the parent plant). One example is the cloudberry plant, which produces seeds but also spreads vegetatively by rhizomes.

This is why you often see Arctic flowers in clusters. This type of reproduction can be so important that the underground plant mass can actually be greater than that aboveground.

Lichens Galore

There are nearly a thousand species of lichens that grow in the severe conditions of the Arctic by anchoring themselves to bare rock, soil, other plants, bones, and even the antlers of caribou. Cold and wind don’t bother them.

They are symbiotic organisms composed of one part fungus and another part photosynthetic alga. The fungus draws nutrients from the substrate and the alga produces energy. The combo can draw moisture from the air when it is available, but it can also become desiccated without harm when it is not.

All in all, the Arctic poses very little challenge to lichens. That said, they are vulnerable to atmospheric pollution, so their presence or absence is a good indicator of a region’s air quality.

Defying Explanation

When learning about living organisms, I find that there are always a few outliers that just seem beg the question: “But why?” The Arctic bladder campion is one such plant, that I suspect would be quite at home on the set of a sci-fi movie.

Peat

I was once asked: “Why does the tundra feel like such a soft, thick carpet?” This is especially true in the southern Arctic and in protected valleys, but less so as you travel through the more austere, gravelly High Arctic. It all goes back to the very slow decay of the plant material mentioned earlier. Rapid decay requires warmth and moisture, which are both lacking in the North. So, the living surface of the ground cover is growing on top of the dead and dying plant parts which grew decades and centuries earlier.

Over thousands of years, the dead parts of the plants accumulate to create a layer of cushioning peat. Eventually the peat is deep enough that it becomes part of the permafrost layer. It is this peat that makes the tundra an important, natural carbon sink—amongst the world’s largest—where more carbon is absorbed than is released into the atmosphere. While the Arctic warms and the permafrost melts, the carbon that is released represents another significant contributor to the greenhouse effect.

Change is Afoot

The Arctic is heating up faster than almost anywhere else on earth. The more temperate world is creeping north, and plant communities are affected. Woody vegetation like dwarf birch is expanding and replacing herbs and grasses, resulting in an overall decline of botanical Arctic specialists.

The seasonal timing of life cycles, both plant and animal, is changing. Since many of these cycles are tightly synchronized, there is little doubt that Arctic warming will cause disruptions both for herbivores and higher up on the food chain. Recent studies show that plant changes are affecting the time of calving for caribou, for example, and, in turn, this could influence lives of the people who depend on caribou.

So, as you northern adventurers experience the tundra, look down at the small marvels at your feet. Beauty is in the detail. Take the time to notice it. And be aware that the snapshot you see is likely to change within the next few decades, or less.