Geography Reference
In-Depth Information
Crisci et al. (2000) distinguished three variants of PAE according to the
units analyzed: localities, areas of endemism, and grid cells. There are sev-
eral other units, such as hydrological basins (Aguilar-Aguilar et al. 2003),
real and virtual islands (Luna-Vega et al. 1999, 2001; Maldonado and Uriz
1995; Trejo-Torres and Ackerman 2001), transects (García-Trejo and Nav-
arro 2004; León-Paniagua et al. 2004; Navarro et al. 2004; Trejo-Torres and
Ackerman 2002), communities (Ribichich 2005), and political entities (Cué-
Bär et al. 2006). García-Barros (2003) proposed a more appropriate classi-
fication based on the objectives of the analysis: to infer historical relation-
ships between areas, to identify areas of endemism, and to classify areas
(as a phenetic association method).
Figure 4.12
Parsimony analysis of endemicity. (a-c) Distributional maps of three
species, with grid cells superimposed; (d) data matrix of grid cells × species; (e)
cladogram of grid cells; (f) area of endemism obtained.
In order to root the PAE cladograms, a hypothetical area with all “0”
is added to the matrix. However, some authors (Cano and Gurrea 2003;
Ribichich 2005) have used an area coded with all “1.” This alternative root-
ing groups areas according to shared absences, which would imply deple-
tion through time starting from a cosmopolitan biota (Cecca 2002).
