Introduction:

Functional traits analysis allows an understanding of the mechanisms that structure plant communities epiphytes. The distribution of taxonomic and functional epiphyte diversity along vertical gradients is a key tool to track epiphytes’ response to environmental changes, especially in biodiversity hotspots, where a high number of endemic species are threatened.

Objective:

To relate the taxonomic and functional epiphyte diversity and their vertical distribution with forest structural variables of the Montane and Dry Forest ecosystems in the Colombian Andes.

Methods:

Epiphyte diversity in each study site was recorded in 35 random phorophytes. Alpha and functional diversity were compared for five vertical strata of the canopy (Z1-Z5) and related to forest structural and floristics variables such as tree richness, tree density, diameter at breast height (DBH), canopy height, crown area, and canopy openness.

Results:

The Montane Forest presented a greater diversity of epiphytes, mainly orchids, with Stelis angustifolia as the dominant species. In contrast, the Dry Forest presented a greater Bromeliad abundance, and Tillandsia recurvata was dominant. Montane forest epiphytes were represented by three functional groups: tank-bromeliads, shallow tank-bromeliads, and ramicauls-orchids, while in the Dry Forest shallow tank-bromeliads and nebulophyte-bromeliads. Positive correlations were found between epiphyte richness, abundance, and diversity with variables related to phorophyte size (DBH and crown area) in montane forest. There was also a different tendency on the preference for some strata between Orchids (Z2-Z3) and Bromeliads (Z3-Z4).

Conclusion:

Differences were found in the taxonomic and functional diversity of epiphytes between the two forests, where orchids and bromeliads often coexist in similar environments but are distributed in different habitats, resulting from adaptation to specific environmental conditions, which allows them to coexist in different niches within the ecosystem.