Thu. Feb 29th, 2024
Arctic-alpine disjunct plants along Lake Superior

Today’s post comes from park naturalist Lesley Ng of Sleeping Giant Provincial Park.

Did you know that there are flowering beauties that are adapted to arctic tundra or alpine environments? In short, they like it cold!

And we don’t need to traverse the tundra or climb mountains to see them. We just need to take a spring hike along the shore of Lake Superior.

Arctic-alpine disjunct plants, eh? What does “disjunct” mean?

Typically, these plants grow a lot However, further north, these plants are separated from their regular distributions throughout the boreal forest. They are therefore “disjoint” or divided from their usual arctic-alpine habitat.

We are not in the Arctic or the mountains, so why are they here?

butterArctic-alpine disjunct plants persist along the shores of Lake Superior in microclimates created by the Great Lake. These cold-loving plants are believed to be relics of the last ice age.

About 10,000 years ago, the Wisconsin Glacier covered most of Canada. When the ice sheet formed, plants normally found in northern regions were pushed south and grew along the ice sheet. As the ice sheets retreated, arctic alpine plants followed.

In colder regions where warmer species could not survive, arctic plants remained. Approximately 100 species have been identified as arctic-alpine disjunctions in the Great Lakes region.

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It’s a hard rock life

Superior’s rugged coastline creates many challenges for all forms of life. The cliffs and cold water temperatures of Lake Superior provide a cold microhabitat for cold-loving species.

saxifrageEmbedded saxifrage (close-up)

These specialized plants withstand the colder temperatures and nutrient-poor soils of rocky cracks and crevices along the coast. Arctic-alpine disjunct plants are often found growing in volcanic and other high-lime, calcium-rich soils. These soils are usually shallow and plant roots have direct contact with the underlying rocks.

Arctic-alpine disjoint plants have a slow growth rate and a very short growing season. These plants are often stunted in height as they must tolerate the cold wind and fluctuating temperatures that Lake Superior brings. Staying low also gives plants a better chance to use the snow as insulation.

Arctic Alps off the coast of Lake Superior

embedded_saxifrage_leavesEvery spring, I make a few trips to the Lake Superior shoreline to feast my eyes botanically. The flowering period is short, but it is always worth the effort!

If you have the opportunity to venture to the shores of Lake Superior in May or early June, you are in the best season to observe arctic and alpine plants!

Grab a camera, put on your plant goggles, and prepare to spend some time hunched over on your hands and knees. You will have to look carefully as these plants fly under the radar and are often overlooked.

These botanical gems are harbingers of spring, a testament to survival, and a reminder of the true power of Lake Superior.

Bird’s eye primrose

Bird's eye primrose

The lobed petals of this plant are set in a distinctive yellow ring in the center. This simple plant with pink flowers measures up to the length of your little finger. It may remind you of a miniature ornamental primrose that is a common find in your local floral department, as they are related.

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Common Buttercup

plain butter

Don’t be fooled by the delicate purple flowers, this plant is carnivorous! Butterflies supplement their nitrogen-deficient diet with unsuspecting insects. Look closely and you can see some of the remains of the plant on its leaves. Its sticky rosette-shaped leaves attract insects and the moment they make contact, it’s game over. They soon realize they are stuck, and as they fight, the plant excretes additional enzymes that eventually suffocate and digest the insect’s nutrients.

Embedded saxifrage

Saxifrage

This plant is a relatively taller arctic plant that prefers north-facing slopes. If you look closely, you’ll notice the white crust on the edges of the succulent-looking leaves of this lime-loving plant. As the liquid evaporates, a layer of lime remains on the tips, which gives rise to the name of this plant.

Because they are important?

Arctic-alpine disjunct plants are indicator species.

This means they help us measure the health of their ecosystem. In particular, their need for a cold habitat helps us monitor the effects of climate change.

Arctic-alpine disjunct plants contribute to biodiversity.

Arctic alpine plants contribute to the richness and diversity of habitats found along the northern shore of Lake Superior.

Support for disjunct plants between the Arctic and the Alps long-term follow-up.

The plants can serve as a reference species for research initiatives, as arctic-alpine species are often found in specialized habitats.