Putting fossils to work in hopes of restoration

Abstract

Paleo detective work is at the core of an emerging field called conservation paleobiology. Its researchers hope to stem the loss of species and ecosystems in a rapidly changing world. In the early 1990s, University of Arizona geoscientist Karl Flessa decided to scout out a new research site in the Colorado River Delta in Mexico. With few roads, it wasn’t easy: his four-wheel drive Chevy Suburban got stuck and he ended up hiring a fishing boat to travel to remote shores and islands in the Gulf of California. Vast beaches of dead clams near the Gulf of California reveal the past impact of water diversions from the Colorado River. They also offer clues as to what it would take to bring back this once-productive ecosystem. Image courtesy of Karl Flessa (University of Arizona, Tucson, AZ) and reproduced from ref. 6. But there was a big scientific payoff: the discovery of vast beaches made out of millions of clam shells. “For a paleontologist, that was a pretty cool thing,” Flessa says. And the discovery came with a mystery: Why had live clams almost completely disappeared? That’s when Flessa had his “duh” moment, he says. The once-productive clam ecosystem must have been wiped out when dams and diversions on the Colorado River cut off the flow of water into the Gulf. “We realized that we could use the dead shells as a window into the past to measure the impact of those diversions, and to ask what it would take to bring the ecosystem back,” Flessa says. From that insight—and similar ones—was born a new scientific discipline, which Flessa dubbed “conservation paleobiology” in 2002. The central idea is that the fossil record isn’t just a look backward; it also offers a crucial guide for strategies to conserve or restore species, communities, …