Geography Reference
In-Depth Information
ent demarcation criteria, with the consequence that the nine approaches are
not mutually exclusive (van Veller 2004). Humphries (2004) found that some
of the approaches and techniques are intended to resolve problems of con-
flicting data, some are explanations of patterns, and some are variations on
cladistic biogeography implementing different optimizing principles, quantit-
ative methods, and spatial models. The main differences with my classifica-
tion (Morrone 2004a, 2005a) are as follows:
• Phylogenetic biogeography, ancestral areas, and intraspecific phylo-
geography are part of dispersalism, sharing the primary objective of
estimating the ancestral areas of the taxa analyzed. It may be argued
that phylogenetic biogeography also takes into account vicariance,
but its use of the progression rule makes it dispersalist. Comparative
phylogeography is very different from intraspecific phylogeography; it
is aimed toward finding general patterns based on the comparison of
the cladograms of different taxa, so it corresponds to cladistic biogeo-
graphy.
• Parsimony analysis of endemicity is included in panbiogeography, hav-
ing the same objective: to identify primary biogeographic homology.
• Event-based methods, which include tree reconciliation and dispers-
al-vicariance analysis, are part of cladistic biogeography.
• One technique of cladistic biogeography (“integrative method”) and an
event-based method (“combined method”) are not techniques in them-
selves but approaches combining methods.
As a consequence of the frequent episodes of geodispersal, biotic evolution
is rarely divergent, resulting in a reticulate rather than branching structure
(Brooks 2005; Hovenkamp 1997; Riddle and Hafner 2006; Upchurch and
Hunn 2002). To analyze this complexity, we should try to discover the in-
stances of vicariance and those where biotic convergence occurred. A step-
wise approach may allow one to identify particular questions, choose the
most appropriate methods to answer them, and finally integrate them in a
coherent framework. Most authors involved in the theoretical development
of biogeography and those who apply their methods usually see them as
representing alternative schools; however, they can be used to answer dif-
ferent questions, which can be different steps of an evolutionary biogeo-
graphic analysis (
fig. 1.1
).
