REVIEW: 'The Next Great Migration,' by Sonia Shah

About 230 pages into her arresting new book, Sonia Shah takes you to a lush mountainside in Hawaii, where a team of research botanists is battling invasive plants. They uproot shrubs, fell trees, capture fugitive seeds — all in an effort to protect the island's native flora.

Sometime later, Shah returns to discover that the scientists have abandoned the mission. Not only did they find it unrealistic but they have begun to think the new species add diversity and strength to that patch of forest.

It's one of many striking examples Shah cites in "The Next Great Migration" to present a novel and important thesis: Migration of people, plants and creatures is not something new and threatening — as we often think today — but a healthy, long-standing characteristic of a living planet. Shah, a science journalist and the author of 2016's highly praised "Pandemic," writes: "Migration is not the crisis: it is the solution."

Midwestern readers will recoil, thinking of recent invaders such as buckthorn and purple loosestrife. But Shah's voluminous research shows that living things have been on the move for millennia, often improving the places where they land. She describes extraordinary migrations — a species of monkey that crossed the Atlantic, a variety of sweet potato that found its way to Polynesia, the koa tree of Hawaii, which begot the tamarind 10,000 miles away — all centuries before humans crossed the seas.

In fascinating passages on mitochondrial DNA and GPS technology, she explains that the vast migrations of plants and birds was pretty much a mystery to scientists until very recently.

As for invasives, she cites a study which found that only 10% of migrating species survive in their new habitats, and only 1% thrive sufficiently to threaten the incumbents. She quotes Stephen Jay Gould: The "moral or practical superiority of 'natives' must be dismissed as romantic drivel."

But Shah has assigned herself a much larger task, for the book also undertakes a critique of Western science since the 18th century, exposing the bigotry that has often poisoned its conclusions. The history of eugenics, "race science" and population studies consume three long chapters — too long, in this reader's view.

It is startling to learn that the revered taxonomist Carl Linnaeus held repellent views toward the people of Asia and Africa. Still, one wishes Shah had devoted less time to social history and more time to the intriguing questions raised by her core thesis. Haven't humans greatly accelerated biology's exodus with the "assisted migration" that brought zebra mussels and Asian carp to North America? Isn't there a difference between the roaming of early hominids and the Syrian genocide that created 5 million refugees almost overnight?

That said, "The Next Great Migration" is both a terrific work of science journalism and a valuable corrective to the latest wave of immigration hysteria sweeping Western nations. Shah closes with a set of heartbreaking mini-profiles — a refugee family from Afghanistan, a teenager fleeing Eritrea, two boys escaping Iraq. One can only admire the courage that drove them to seek a better life in a strange new place and hope that we can regard them with open hearts and open minds.

David Hage is a former writer and editor at the Star Tribune.

The Next Great Migration

By: Sonia Shah.

Publisher: Bloomsbury, 400 pages, $28.