The geographic range size and vulnerability to extinction of epiphytes
in the Atlantic Forest of Brazil
Abstract
Epiphytes have long been reported to have larger geographic ranges than
terrestrial species, despite evidence of their outstanding diversity and
endemism. This apparent contradiction calls for further investigation of
epiphytes’ poorly understood range size patterns. Here, we address the
question of whether epiphytes have larger geographic ranges than
terrestrial species in the Atlantic Forest of Brazil, a global centre of
epiphyte diversity. In contrasting the extent of occurrence and area of
occupancy of 12,679 epiphytes and non-epiphytes at varying taxonomic
scales, we found that epiphytes have among the smallest geographic
ranges of flowering plants and likely a high vulnerability to species
extinction. We found no evidence that epiphytism leads to differences in
geographic ranges between close relatives. However, epiphytes and
non-epiphytes in epiphyte-rich lineages share many diversification
mechanisms and ecological adaptations (‘epiphyte-like traits’), which
probably explains why both sets of species have small range sizes and
high vulnerability to extinction.