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Epiphytes, plants that germinate and root non-parasitically on other plants at all stages of their life, constitute one of the most prominent life forms in the canopy of the tropical forests on Earth. Epiphytes, have been considered particularly vulnerable to climate change and forest loss because of their existence at the interface of vegetation and atmosphere. In humid tropical forests, one of the biomes where an increase in extreme temperatures is expected for long periods of time (heat waves), vascular epiphytes (e.g.,orchids, bromeliads, and ferns) can represent up to 50% of the diversity of local vascular flora, while globally they constitute about 10% of plant diversity. In the Neotropics, for example, in the forests of Ecuador, vascular epiphytes represent up to 39% of the flora, while in Brazil, Colombia, Costa Rica and Panama, they contribute with 23-26% of the plant species diversity. In general, epiphytes are highly dependent on tree structure and environmental quality, drastically reducing their abundance and diversity in disturbed ecosystems. Land-use change has dramatically impacted tropical forests resulting in degraded landscapes with fragmented forests in different states of conservation, and embedded in a mosaic of agricultural and livestock patches. This condition impacts the dispersal and natural regeneration processes of plant communities. For many epiphyte species, it reduces dispersal opportunities since they require well-established tree communities to survive. Here, we present advances on the conservation status of epiphytes according to The International Union for Conservation of Nature (IUCN) for species in Brazil, Colombia, and Mexico. In addition, for selected species we evaluated the impact of deforestation on species distribution and habitat loss due to increasing temperature. Given that many epiphyte species are endemic, and many are represented by only few records, considerably more studies are needed to assess the conservation status of more species and –if possible– vascular epiphytes as a group. Our knowledge of diversity and ecology of epiphytes is still incipient, and data on epiphyte species distribution in degraded forests are extremely scarce. Our results indicate that deforestation represents the greatest impact on epiphyte diversity due to habitat loss, followed by ecosystem degradation and conversion of forests to agricultural systems. However, even if epiphyte species richness loss is imminent, the diversification of epiphyte phylogenetic diversity may imply high resistance to environmental filters produced by climate change and landscape transformation.

Keywords:

vascular epiphyte, tropical forest, climate change, diversity, species distribution, disturbances

Ana Benavides, Sven Batke, Helena Einzmann, Joao Elias, Edilia de la Rosa-Manzano, Alejandro Flores-Palacios, Valeria Guzmán-Jacob, Florian Werner, Maria Judith Carmona, Flavio Ramos, Daniel Zuleta, Thorsten Krömer, Glenda Mendieta Leiva

Presentation within symposium:

S-13 Vascular epiphytes: current knowledge and future challenges

Identification of responses to anthropogenic disturbances and Climate Change on vascular epiphytes

-Review-