Occupancy is the proportion of sites within a given area where a species
is present. This parameter is central in conservation biology because it determines
the probability of persistence of a species through time. That is, a species is more
likely to persist longer in areas where it has high occupancy than in areas where its
occupancy is low. The distribution map of Bignonia heterophylla, selected here
as the focal species, shows that occupancy is higher in Central America than in South
America. In this case, the lack of presence records (i.e., collections) in the areas
of South America that match the ecological niche of the focal species is not the result
of lack of botanical work aimed at documenting the occurrence of plant species through
collections. Rather, it reflects true absence, or low occupancy, of the focal species.
The localities where a focal species, Bignonia
heterophylla, has been collected are indicated by red points, and the areas that
match the ecological niche of the species are shown in gray. Note that the latter
extend beyond areas of known occurrence.
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