When are extinctions simply bad luck? rarefaction as a framework for disentangling selective and stochastic extinctions

1. A key challenge in conservation biology is that not all species are equally likely to go extinct when faced with a disturbance. Traditionally, differences in species extinction risk are considered a form of extinction selectivity, a nanrondom process by which species’ extinction risks are associated with their traits. While selectivity clearly contributes to varation in extinction among taxa, it is also clear that rare species are more likely to go extinct than are common species. While obvious, this law of extinction suggests that random chance, operating on species abundance, plays an important role in the extinction process. Unless ecologists and conservation biologists can disentangle random and nonrandom extinction processes, then the prediction and prevention of future extinctions will continue to be an elusive challenge. 2. We suggest that a modified version of a common null model procedure, rarefaction, can be used to disentangle the influence of stochastic species loss from ...