have been uncovered in comparative phylogeographic surveys of regional biotas in several other parts of the world (Bermingham and Moritz, 1998; Avise, 2000). In at least several cases, the current boundaries between ESUs tend to be spatially concordant with transition zones between zoogeographic provinces as identified by more traditional evidence (such as species’ ranges and faunal distributions). Such concordance suggests that similar types of evolutionary forces [perhaps operating as detailed in Avise (2000)] may be responsible for both of these seemingly unrelated biogeographic phenomena.

The phylogeographic observations discussed above suggest that a concept—of Pleistocene Parks or Phylogeographic Sanctuaries—might be added to the compelling list of scientific rationales for earmarking particular regional nature reserves. Such nature reserves (like those based on traditional biodiversity hotspots) would protect and highlight the distinctive “legacy biotas” they contain, in much the same way that traditional historical landmarks (such as Civil War battlegrounds) honor important legacy events in human affairs. A carefully designed archipelago or network of phylogeographic reserves on each continent and in each marine region could thus add an emotive element of historical legacy to the catalog of societal inducements to preserve biodiversity. Furthermore, a widely promoted concept of Pleistocene Parks (like the evocative notion of Jurassic Park) might resonate well with the public and policymakers. It also might dovetail nicely with the PANGEA WORLD initiative discussed above and perhaps also with proposals to “re-wild” ecosystems with Pleistocene-like biotas (Martin, 2005).

Thus, a compelling assignment for the field of comparative phylogeography will be to map the spatial and temporal dimensions of Earth’s remaining genealogical capital on all of the world’s continents and ocean regions (a task already well initiated in several areas, such as Europe and parts of North America). A comprehensive phylogeographic inventory of Earth’s microevolutionary history will complement ongoing attempts to identify and catalog all extant species [see Blackmore (2002)], and it also will complement ongoing appraisals of Earth’s macroevolutionary history in the Tree of Life project. An overarching practical mission will be to incorporate information from all of these integrative endeavors into meaningful conservation plans, notably with regard to implementing the concept of regional sanctuaries for nature (Moritz and Faith, 1998).