Geography Reference
In-Depth Information
there are two possible interpretations for PAE cladograms: static and dy-
namic. The former assumes that cladograms constitute an alternative to
pheneticclassificationmethods,whereasaccordingtothelatter,cladograms
are hypotheses on the historical or ecological relationships of the areas ana-
lyzed. If we interpret the external area with all “0” as an area lacking suitable
conditions for the taxa to survive therein (ecological interpretation), relation-
ships will indicate ecological affinities. If we interpret the external area as
a geologically ancient area, where none of the taxa has yet evolved (his-
torical interpretation), relationships will indicate biotic interchanges or vicari-
ance events. Most of the authors who have used PAE explored historical
interpretations of the detected patterns, usually from a vicariance viewpoint;
for ecological interpretations, see Trejo-Torres and Ackerman (2002), Trejo-
Torres (2003), and Ribichich (2005).
Enghoff (2000) considered PAE an extreme “assumption 0” approach
because only the widespread taxa provide evidence of area relationships.
Morrone and Márquez (2001) and Brooks (2005) considered PAE an in-
complete implementation of Brooks parsimony analysis (BPA). Szumik et
al. (2002) criticized the use of PAE for identifying areas of endemism be-
cause an explicit optimality criterion is used a posteriori to select areas of
endemism found by what they considered less appropriate means. Brooks
and Van Veller (2003) criticized the use of PAE as a cladistic biogeographic
method, which is erroneous because it has a different objective. Parenti and
Humphries (2004) suggested that PAE adopts protocols directly from phylo-
genetic systematics and violates some of the basic assumptions of cladistic
biogeography.
Nihei (2006) presented a revision of PAE, including a discussion of its
history and applications. He suggested that most of the criticisms dealt with
its method rather than its theory and that they usually resulted from the con-
fusion between the dynamic and static approaches. Nihei warned biogeo-
graphers applying PAE to be aware of the problems and limitations of both
dynamic and static PAE and to evaluate new variations of PAE.
Algorithm
PAE-PCE consists of the following steps (Craw 1989b; Crisci et
al.2000;Grehan2001c;Lomolinoetal.2006;Morrone1994b,2004b;Posa-
das and Miranda-Esquivel 1999; Vargas 2002):
1. Construct an
r
×
c
matrix, where
r
(rows) represents the units analyzed
(e.g., localities, distributional areas, grid cells) and
c
(columns) represents
the taxa. Each entry is “1” or “0,” depending on whether the taxon is
