When National Geographic magazine came out with their cover story on de-extinction in April 2013, it set off quite a controversy. Now that we are on the scientific brink of being able to bring back long-gone species, proponents and critics are hotly debating whether we should.
An intriguing side issue to this discussion relates to our native landscapes and the biodiversity they provide—and how quickly we’re losing them. We know that extirpated animals performed vital services in their ecosystems, which benefit when they return.
Could de-extinction, then, achieve a similar result?
The wolves of Yellowstone National Park
Landscape restoration is defined as the attempt to reverse human impact by returning an ecosystem or habitat to an earlier state; or as some call it, its “predisturbance situation.” Restoration means trying to copy a specific historical structure; in a sense, turning back the environmental clock. Some say restoration is more aptly characterized as making the environmental clock tick again. Standard examples of such efforts include eliminating nonnative, invasive animal or plant species and reintroducing formerly native species.
The wolves of Yellowstone are probably one of the most well-known examples of reintroducing a native species. During the wolves’ 70-year absence from the park as a result of being killed off by humans, elk were free to roam, reproduce and feed on the region’s small aspen shoots. Starting in 1995 when the wolves were reintroduced, the elk’s fear and reduced population improved the aspens’—a tree species in decline all over the West—chances for survival. From the 1920s to the early 1990s, when wolf packs were absent in Yellowstone, no new aspen trees that hadn’t suffered from animal browsing were found. The first time that significant aspen growth was documented was after the wolves came back. In the past few decades, a large number of aspen trees have reached heights of more than seven feet, key for long-term survival because it places the crowns high enough to keep them safe from elk.
Aspens aren’t the only landscape beneficiaries of the wolves’ return. In the absence of their predators, elk not only chewed on trees but browsed heavily in the open flats along rivers and wetlands. Without a predator to evade, there was no reason for them to seek thicker cover. Since the Yellowstone wolves have come back, elk spend more time in the safety of dense vegetation or on the move. As a result, riparian areas that had been suppressed by decades of overbrowsing are regenerating, improving habitat for species such as beavers and songbirds. Beavers, which create wetlands with their dams, have improved water quality in streams by trapping sediment, replenishing groundwater and cooling water.
According to the Wyoming chapter of the Sierra Club, other species that rely on healthy riparian habitats and benefit from the presence of wolves in Yellowstone National Park include:
- small mammals (muskrats and other rodents),
- songbirds (warblers, wrens, and thrushes),
- waterfowl (ducks, geese, trumpeter swans) and
- Yellowstone cutthroat trout and other native fish.
The woolly mammoths of Siberia
So, we know that returning extirpated wildlife can restore native landscapes. But now that we’re capable of bringing back long-extinct species, landscape restoration by the use of wildlife takes on a new twist.
Twelve thousand years ago, northern Siberia was home to woolly mammoths and other big, grazing mammals. Back then, the landscape was not moss-dominated tundra as it is today but grassland.
Sergey Zimov, a Russian ecologist and director of the Northeast Science Station in Chersky, believes that this was no coincidence; the numerous herbivores maintained the grassland by breaking up the soil and fertilizing it with their manure. Once they disappeared, moss took over and transformed the grassy steppes into less productive tundra.
In recent years, Zimov has tried to turn back time on the tundra by bringing European bison, musk ox, Yakutian horses and other big mammals to a region of Siberia he calls Pleistocene Park. His theory is that by filling the vast, Russian Arctic with grass-eating animals, we can slow global warming. Today, climate change is being felt most sharply in the Arctic, where temperatures are warming faster than anywhere else on the planet. Zimov states that his herbivores will keep wild grass short and healthy, causing it to send up fresh shoots through the summer and fall. In winter, the animals will trample and flatten the snow that otherwise would insulate the ground from the cold air. That helps prevent the permafrost from thawing and releasing powerful greenhouse gases. Grass also reflects more sunlight than forests, a further impediment to global warming. Climate scientists and environmentalists are watching Zimov’s Pleistocene Park project closely.
Skeptics say, however, that it will take millions of animals to change the landscape of Siberia and effectively seal the permafrost. But Zimov says that left alone, big grazers such as bison, caribou and musk ox multiply quickly.
He believes the next step—with the help of de-extinction scientists—may be to bring in the woolly mammoths.
Do you think that landscape restoration is a compelling reason to support de-extinction?
Here’s to finding your true places and natural habitats,