This function returns a list containing three shapefiles derived by
information supplied by GIFT. "regs" includes all the features corresponding
to regions where the species has been listed as present. "regs_native"
includes all the features corresponding to regions where the species has
been listed as native. And "regs_alien" includes all the features
corresponding to regions where the species has been listed as alien.
Arguments
species
character, species binomial name
min_size
numeric, minimum size of checklists (in km2) to be included
in the analysis.
max_size
numeric, maximum size of checklists (in km2) to be included
in the analysis.