Vascular epiphytes in Argentinian Yungas: Distribution, diversity, and ecology

Abstract

Vascular epiphytes are an important component of the flora of subtropical regions, but they remain understudied compared to tropical regions. Subtropical montane region of Yungas in Argentina has high epiphyte diversity, but information on epiphytes remain in little disseminated sources such as herbariums, theses and publications not available on the web. The objective of this study was to describe the distribution and diversity of epiphytes and to review ecological research on epiphytes in Yungas of northwestern Argentina. Occurrence records of epiphytes were compiled to prepare a floristic list, to describe spatial bias, and latitudinal and altitudinal patterns. There are 168 epiphyte species in Argentinian Yungas, which belong mainly to the families Orchidaceae, Bromeliaceae, and Polypodiaceae. Most species are holoepiphytes and facultative epiphytes (83%), and the rest are trees, herbs, and shrubs that occasionally occur as epiphytes. The species richness of the 14 most abundant epiphyte species in this region peaks at 1500 m, and decreases at higher and lower elevations. Most trees with a diameter at breast height ≥ 10 cm (62.2%) are epiphyte hosts, and epiphytes are most diverse in larger than in smaller native trees of this region. Species richness and cover of epiphytes increased with the diameter at breast height of Ocotea porphyria, the most important host tree for epiphytes in this region. It is expected that this study will serve to acknowledge the high diversity of epiphytes in the region and identify gaps in knowledge for new sampling and studies.