Remove a particularly important species from an ecosystem and the catastrophic consequences can ensue. This, in painfully abbreviated form, is the summary of what must be considered the most significant study of the illustrious career of the great ecologist Robert T. Paine, who died this week. The notion that removing a critical species - a keystone species, to use the term Bob coined - can lead to a crash in diversity may seem obvious enough today, but it was anything but in 1969. This was the year in which Bob published his research on the effects of predation by the sea star
Pisaster on the intertidal communities on the lands of the Makah Nation on the far northwest tip of the Olympic Peninsula. One might expect that the removal of the ecosystem's top predator would cause its prey to become common across the board, but instead the removal of sea stars released mussels from their main form of population control, allowing them to take over swathes of the intertidal and driving out almost all - indeed, in some cases, all - other animal species. Because of the importance of
Pisaster in controlling diversity on the rocky shores of the Northwest, it was likened to a keystone in an arch which, if removed, will cause the entire structure to collapse. The concept of keystone predators has since grown to become one of the most important in all of ecology, informing studies in areas as diverse as conservation biology and my own field of paleoecology. It is also unquestionably the largest academic feather in Bob's cap (which is so covered in feathers that it resembles the head of one of the coastal birds whose calls he could so precisely identify and interpret), but I would argue that the idea of keystone species was not Bob's greatest contribution overall. Somewhat ironically, a man best known for analyses of what happens when when an important player is removed from a community had his most profound impact by adding to the ranks of the scientific community. By mentoring generations of students and postdocs, who themselves would go on to mentor others, he was the father of what has quite reasonably been described as a dynasty of ecologists, the impressive scope of which is best appreciated in
visual form. It was in 2003 in the capacity of a summer research assistant for two of Bob's former students,
Cathy Pfister and
Tim Wootton, that I met Bob, who accompanied us on several trips to Tatoosh Island, one of the world's great natural laboratories. I doubt he would have remembered me (and, given that I was fairly new to ecology at that point and exceedingly new to serious field work, this is probably for the best), but to have been even a bit player in the saga of one of the century's great biologists has been one of the great honors of my life thus far. Even my relatively brief interaction with him, with his students, and with his students' students, was enough to impress upon me the significance of his legacy. Cooperating with the Makah, he established a study area on Tatoosh and on nearby areas of the mainland that has been the focus of active research since the '60s, and for anyone interested in the long-term effects of changes in climate and other ecological variables, the importance of such an extensive data set cannot be overstated. One of my most enduring memories of Bob was a discussion we had after dinner one evening, in which he talked about his pride not only having established the research program on Tatoosh but in knowing that he had inspired others to ask similar questions to those he had been asking, meaning that this program would perpetuate itself well into the future. Perhaps this moment of self-reflection stands out to me because of Bob's generally (though good-naturedly) cantankerous demeanor (another enduring memory I have of that summer is him knocking down swallow nests in our sleeping area before a visiting scientist arrived, since he was concerned they had "a mystical view of nature" but was under no circumstances going to sleep beneath what amounted to a guano factory), but it also stands out because it was so clearly true. In a field that is often accused of relying heavily on models and on extrapolations beyond available data, Bob understood better than anyone the value of data gathered in the field for answering some of the most important scientific questions of our age. This understanding is what made him a titanic figure in ecology, and his ability to impart this understanding and his enthusiasm for field-based experimental research is what truly cemented this status. His prowess as a researcher means his death will leave a huge hole in the world of ecology, but the legion of ecologists he inspired will insure that the community of which he was a part will continue to thrive.
