Beyond the species–area relationship: improving macroecological extinction estimates

Summary The species–area relationship is often used to predict extinction rates following habitat loss and climate change. This metric, however, has several shortcomings for conservation applications, as it does not predict extinction risk for individual species, only predicts the expected number of extinctions without an associated measure of uncertainty, and assumes that a species is protected if one individual of a species remains in a landscape. Here, we propose two new metrics, the extinction–area relationship and probabilistic species–area relationship, that address these shortcomings, and present equations for each metric based on empirically well‐supported species abundance and spatial abundance distributions. Extinction predictions are found to be strongly influenced by the choice of a minimum abundance required for a species to be considered protected, a parameter that cannot be adjusted explicitly in the classic power law form of the species–area relationship. These new metrics provide a flexible and theoretically grounded means of applying macroecological principles to the prediction of extinction.