The ecology of black swans
David Hume once famously observed that the theory that “all swans are black” would be disproven by the observation of a single black swan. Nicholas Taleb has popularized the use of the term “black swan” to describe the often unexpected events that violate or modify our existing theories. I’ve been thinking about what black swans mean for ecological research, and some of my thoughts scare me. Ecologists are increasingly promising to forecast the effects of global change on species. The problem is that the models used for these forecasts are quite uncertain, and definitely not of the precision of those in physics or chemistry. Moreover, even if the models do turn out to be correct, ecologists are attempting to forecast well outside the range of the data that were used in construct the model. In essence, ecologists are being asked to predict the response of a novel unreplicated experiment- always a bad situation for a scientist to be in! The “black swans” of global change will inevitably occur, and perhaps all ecologists can hope to do is firmly state that they will occur and perhaps estimate their potential order of magnitude. How big could the black swan be?
