¹Laboratoire Génétique et Environnement, Institut des Sciences de l'Évolution, CC065, USTL, Place E. Bataillon, 34095 Montpellier Cedex 05, France

Correspondence: F Rousset, Laboratoire Génétique et Environnement, Institut des Sciences de l'Évolution, CC065, USTL, Place E. Bataillon, 34095 Montpellier Cedex 05, France. E-mail: rousset@isem.univ-montp2.fr

Received 14 October 2002; Accepted 12 February 2003.

Abstract

A coalescent argument is used to derive the effective size in simple models with recurrent local extinctions. Several alternative methods of derivation of this result are given and compared to earlier analyses of this problem. The different methods described in this paper all give the same result, which differs from earlier ones. For two published sets of estimates of demographic parameters, metapopulation structure appears to result in a moderate reduction of effective size relative to total adult population size.