How demographic stochasticity can slow biological invasions

Ecologists have traditionally neglected demographic stochasticity in describing the spread of an invading species. However, the region most critical in determining wave speed is often the leading edge, precisely the point where demographic stochasticity is most pronounced. In this paper, I analyze a common class of one-dimensional, single-species invasion models and find that, for very general conditions, demographic stochasticity slows biological invasions. Nonetheless, the slowing is not large enough to be noticeable in most ecological time series. 1 also briefly discuss the role of transient dynamics and rare, long-distance dispersal.