(Plant) Life in a Disaster Zone

As I walked through the exhibition Nature Unleashed at the museum, the stories that struck me most proudly were those of resilience and recovery. Endurance and rebuilding (most notably New Orleans after Hurricane Katrina) leapt off the walls and struck a chord with me. Of course, while my empathy was focused on the people, rebuilding and recovering, the scientist in me was thinking about how the environment would be regenerating, too.

A cone and needles growing from a branch.

Tamarack (Larix laricina) is a tree well adapted to life in a burn zone. Because its cones open in the heat and release their seeds, the species regenerates quickly after a fire. Image: Cassandra Robillard © Canadian Museum of Nature

Ecosystem regrowth after an existing ecosystem is damaged is called secondary succession. As a botanist, I’ve learned that many plant species are exceptionally well adapted to such cycles of disturbance and restoration. Before insects, birds and mammals return, plants move into the recovering ecosystem and provide the substrate for everything else.

Take pine, spruce and tamarack trees, for example: these conifers need the heat from forest fires to release the seeds from their cones. Without fire, these trees cannot successfully reproduce. When the seeds are dispersed, they find a sunny and open burn zone to germinate and thrive in—where previously a dark, tall forest once stood. The same is true for the aptly named fireweed (Chamerion angustifolium). This plant forms dense purple swathes through burned areas, and readily colonizes disturbed sites throughout the boreal forest. The establishment of these plants is often the first step on the path back to the state of the forest before the burn.

Several flowers bloom on a stem.

Fireweed (Chamerion angustifolium) is one of the first signs of plant life returning to the boreal forest after a fire. Image: Paul C. Sokoloff © Canadian Museum of Nature

So, if re-vegetation after disturbance is called secondary succession, what do you call the process of an ecosystem forming on a brand-new land mass? Primary succession, of course!

Although rare, new niches for species to colonize can open up after a glacial retreat, tectonic upheaval, or even volcanic eruption. The most well-known example in recent memory is Surtsey, a volcanic island that formed in 1963 off the southern coast of Iceland.

A rocky landscape showing two patches of distinct vegetation.

Seabeach sandwort (Honckenya peploides; foreground) and Arctic dunegrass (Leymus mollis; background) in the Canadian Arctic. Seabeach sandwort and a relative of Arctic dunegrass, European lymegrass (Leymus arenarius), were some of the first colonizers of the volcanic island Surtsey. Image: Roger Bull © Canadian Museum of Nature

Since its dramatic introduction to the planet, Surtsey has been studied by scientists of every stripe seeking to uncover how the continents and ecosystems that we call home came into being. Some of the first plants to become established on this island were the seabeach sandwort (Honckenya peploides), and European lymegrass (Leymus arenarius). These plant species stabilized the loose sand that comprised the beaches, forming resilient dunes and thus allowing other species to gain a foothold in this initially inhospitable place.

A scan of the herbarium sheet for Honckenya peploides CAN241259.

This specimen of seabeach sandwort (Honckenya peploides) in the museum’s collection comes from Iceland. This species is one of the first plants to become established after volcanic eruptions—something not uncommon in that island nation. Image: Paul C. Sokoloff © Canadian Museum of Nature

As the ecosystem on Surtsey or any new land mass develops, so too will the mechanisms that restore an ecosystem after a disaster. Seeds will be deposited in the soil and await the right conditions to sprout, and the soil will gain nutrients as plants die and decompose. Should nature again be unleashed, the stage will already be set for an ecosystem recovery.

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