Bob Paine is nearly 2 meters tall and has a powerful grip. The ochre sea star, however, has five sucker-lined arms and can span half a meter. So when Paine tried to prise the creatures off the rocks along the Pacific coast, he found that his brute strength simply wasn't enough. In the end, he resorted to a crowbar. Then, once he had levered the animals up, he hurled them out to sea as hard as he could. “You get pretty good at throwing starfish into deeper water,” he says.
It was a ritual that began in 1963, on an 8-meter stretch of shore in Makah Bay, Washington. The bay's rocky intertidal zone normally hosts a thriving community of mussels, barnacles, limpets, anemones and algae. But it changed completely after Paine banished the starfish. The barnacles that the sea star (Pisaster ochraceus) usually ate advanced through the predator-free zone, and were later replaced by mussels. These invaders crowded out the algae and limpets, which fled for less competitive pastures. Within a year, the total number of species had halved: a diverse tidal wonderland became a black monoculture of mussels.
By re-engineering the coastline in this way, Paine dealt a serious blow to the dominant view in ecology of the time: that ecosystems are stable dramas if they have a diverse cast of species. Instead, he showed that individual species such as Pisaster are prima donnas, whose absence can warp the entire production into something blander and unrecognizable. He described these crucial creatures, whose influence far exceeds their abundance, as keystone species, after the central stone that prevents an arch from crumbling. Their loss can initiate what Paine would later call trophic cascades — the rise and fall of connected species throughout the food web. The terms stuck, and 'keystone' would go on to be applied to species from sea otters to wolves, grey whales and spotted bass.
Today, ecology students take these concepts for granted — but they shook the field when Paine first articulated them in the 1960s. “He's been one of the most influential ecologists in the last half century,” says Simon Levin, a mathematical ecologist at Princeton University in New Jersey, and one of Paine's closest friends. The revelation that not all species are equal was as disruptive to ecology as the loss of Pisaster was to Makah Bay. So was Paine's insistence on tinkering with nature — what some have called kick-it-and-see ecology — at a time when most ecologists simply observed it.
But Paine — an organism whose disproportionate influence equals that of any starfish or sea otter — has also changed the ecosystem of scientists. In his five-decade career, he has trained a thriving dynasty of around 40 students and postdocs, many of whom are now leading ecologists themselves and who consider their time with Paine formative. They include Paul Dayton at the Scripps Institution of Oceanography in La Jolla, California, who has shaped understanding of rocky shores, kelp forests and Antarctica's sea floor; Bruce Menge at Oregon State University in Corvallis, who expanded Paine's research to coasts worldwide; Jane Lubchenco, who heads the US National Oceanic and Atmospheric Administration (NOAA) in Washington DC; and Steve Palumbi at Stanford University in California, who used genetics to track the illegal trade of whale and dolphin meat.
“There are other ecologists as famous as Bob, but if you look at their list of students, there aren't nearly as many whom you know by reputation,” says Chris Harley at the University of British Columbia in Vancouver, Canada, who was one of Paine's most recent PhD students. Once Paine's students' students are taken into account, his academic family easily stretches into the hundreds. “Everyone is tied to Paine,” says Craig McClain, a deep-sea biologist at the National Evolutionary Synthesis Center in Durham, North Carolina, who is three links removed — his postdoctoral adviser was Dayton's student.