Ecology, biogeography and diversity of the Bolivian epiphytic cacti — with the description of two new taxa

Abstract

We provide an overview of the taxonomy, ecology, and biogeography of the epiphytic cacti of Bolivia, which is second only to southeastern Brazil as a centre of epiphytic cactus diversity in South America. Twenty-one obligatory or facultative epiphytic species with 2 varieties in 7 genera occur in Bolivia. A further 14 species in 6 normally terrestrial genera are recorded as accidental epiphytes. Two taxa are described as new: Lepismium asuntapatense sp. nov. M. Kessler, P.L. Ibisch & Barthlott and Rhipsalis baccifera ssp. nov. cleistogama M. Kessler, P.L. Ibisch & Barthlott. Eight species are endemic to Bolivia, mostly in humid montane forests. Preliminary ecograms and extrapolated range maps for all obligatory epiphytes are provided. GIS-overlay of the range maps is used to predict the species diversity patterns for all obligatory epiphytes and for the genera of Rhipsalideae. Species-richness is highest in humid montane forests, but physiognomically and in relation to overall species-richness of vascular epiphytes, epiphytic cacti are most important in semi-humid montane forests of inter-Andean valleys and the Chaco zone. Three species are classified as vulnerable and all others as not endangered.