The founder space race: a response to Waters et al.

Abstract

We welcome the attempt by Waters et al.[1], in the spirit of the journal that they are publishing in, to address scales not typically dealt with by ecology (too long) or evolution (too short). The basic scenario that they address [i.e., the expansion of the range of a taxon (species, population, or genotype) into empty niche space], is a nonequilibrium situation in which many ecological processes occur. However, the timescales they refer to range from very short (a few generations) to very long (thousands to millions of generations). They suggest that a ‘founder takes all’ principle might explain reduced genetic diversity in recently colonised areas. We are concerned that their use of the term ‘density-dependent effects’ to describe how genetic structure within newly colonised areas impedes establishment of invading taxa misrepresents the process and does not address all the main mechanisms by which this can occur.