Effect of forest successional stage on the host-epiphyte orchid relationship in the Pindo Mirador biological station, Ecuador

Epiphyte diversity in forest ecosystems is closely related to forest structure; however, in the Pindo Mirador Biological Station in Ecuador, there are no studies documenting this interaction. Eight plots of 0.1 ha each were established, four in the secondary forest and four in the primary forest, with the objective of evaluating the effect of the current successional stage of the forest on the host-epiphyte orchid relationship in that station, based on the behavior of forest structure factors and orchid diversity. All epiphytic orchids present and host trees were recorded by measuring their diameters and heights (total and stem), comparing richness and abundance by stage and host, and applying a Canonical Correspondence Analysis between forest structure variables and epiphyte records by plots. It was detected that the main feature of the horizontal structure of orchid epiphytism is the higher abundance and lower richness in the secondary forest, occurring the opposite in the primary forest. With respect to the vertical structure, a greater abundance of orchids in the highest part of the stem of the hosts in the secondary forest, while in the primary forest they predominate at the base of the main branches, concluding that the successional stage of the forest affects both the richness and abundance of orchids on the basis of the changes experienced by the forest structure, in each of them.