As long as it has been known to science, the diminutive western swamp tortoise has been in peril. By the time it was formally named in 1901—using a decades-old museum specimen—Pseudemydura umbrina was presumed extinct. And since it was rediscovered in the 1950s, biologists have struggled to protect it from the twin threats of habitat loss and introduced predators, which drove its numbers to bottom out at just 30 individuals in the 1980s. Now that climate change poses an even more urgent threat to the endangered tortoise, biologists have a controversial plan to safeguard its future—by moving it to new sites outside of its known historical range. The translocation, which took place today, makes the tortoise the first vertebrate to be deliberately relocated because of climate change.
The yearlong trial, several years in the planning, will track 12 captively bred juvenile tortoises released to each of two sites roughly 250 kilometers south of their native habitat on the outskirts of Perth, Australia. Although the sites aren’t ideal for the tortoises now, detailed modeling of rainfall, temperature, swamp hydrology, and tortoise biology predict they will be in half a century.
The trial will be a contentious test case in conservation circles. Introducing nonnative species into new ecosystems has an ignominious history, not least in Australia, where the deliberately introduced European red fox and domestic cat have wreaked havoc on native wildlife. But the idea of assisted colonization has gained some favor over the past decade as conservationists grapple with the impacts of rapidly changing climate on habitat suitability for numerous flora and fauna.