A presence-absence matrix (sites in rows and species in columns,
with the first two columns containing the longitudinal and latitudinal coordinates,
respectively), or an object of class PresenceAbsence.
method
The method used to calculate the overlap matrix. "Chesser&Zink"
calculates the degree of overlap as the proportion of the smaller range that overlaps
within the larger range (Chesser & Zink 1994). "Proportional" calculates the proportion
of a range that overlaps another range, the resultant matrix is not symmetric.
"Cells" will show the number of overlapping grid cells between a pair of species'
ranges (same for both species in a pair), here the resultant matrix is symmetric.
xy
Logical, if TRUE the input matrix contains geographic coordinates in
the first two columns.
References
Chesser, R. Terry, and Robert M. Zink. "Modes of speciation in birds: a
test of Lynch's method." Evolution (1994): 490-497.
Barraclough, Timothy G., and Alfried P. Vogler. "Detecting the geographical
pattern of speciation from species-level phylogenies." The American Naturalist 155.4
(2000): 419-434.