Fig. 1.

Species persistence times. Persistence time τ within a geographic region is defined as the time incurred between a species’ emergence and its local extinction. Recurrent colonizations of a species define different persistence times. The number of species in the ecosystem as a function of time (gray shaded area) crucially depends on species emergences and persistence times. We analyze two long-term datasets about North America breeding birds (22) and herbaceous plants from Kansas prairies (23). (Inset) Observational routes of the Breeding Bird Survey. Aggregating local information comprised in a given geographic area, we reconstruct species presence–absence time series that allow the estimation of persistence-time distributions.