The maintenance of genetic polymorphism in small island populations: large mammals in the Hebrides

In this chapter we seek to emphasize a particular virtue of island populations: they can be used to evaluate the population genetic processes responsible for changing allele and genotype frequencies, and hence levels of genetic variation. This virtue is distinct from the more commonly discussed merits of island populations for investigating speciation, which occupy most of the other contributions to this book, and for investigating loss of genetic variaton in island-hopping founder events, exemplified by Gilbert et al. ‘s (1990) investigation of California Channel Island fox (Urocyon littoralis) populations.