A great deal of effort is spent protecting geographically peripheral p
opulations of widespread species. We consider under what conditions it
is appropriate to expend resources to protect these populations. The
conservation value of peripheral populations depends upon their geneti
c divergence from other conspecific populations. Peripheral population
s are expected to diverge from central populations as a result of the
interwoven effects of isolation, genetic drift and natural selection.
Available empirical evidence suggests that peripheral populations are
often genetically and morphologically divergent from central populatio
ns. The long-term conservation of species is likely to depend upon the
protection of genetically distinct populations. In addition, peripher
al populations are potentially important sites of future speciation ev
ents. Under some circumstances, conservation of peripheral populations
may be beneficial to the protection of the evolutionary process and t
he environmental systems that are likely to generate future evolutiona
ry diversity.