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.
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.
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.
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.
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.