Invasion by extremes: population spread with variation in dispersal and reproduction.

摘要: abstract: For populations having dispersal described by fat‐tailed kernels (kernels with tails that are not exponentially bounded), asymptotic population spread rates cannot be estimated traditional models because these predict continually accelerating (asymptotically infinite) invasion. The impossible predictions come from the fact fitted to data have a quality (nondiscrete individuals and, thus, no moment‐generating function) never applies data. Real organisms produce finite (and random) numbers of offspring; an empirical function can always determined. Using alternative method estimate in terms extreme events, we show estimates derived for kernels, and demonstrate how variable reproduction modifies rates. Whereas define rate as speed advancing front describing expected density individuals, our alternative...