# Tropical forest disturbances reveal increase in stress-tolerant(s) strategy among epiphytes while simplifying the taxonomic and layer structure of epiphytic communities

## TL;DR

Disturbed tropical forests see a rise in stress-tolerant epiphytes and a loss of species diversity and canopy layering.

## Contribution

This study applies Grime’s CSR strategies to epiphytes for the first time, revealing their unique response to forest disturbances.

## Key findings

- Stress-tolerant (S) epiphytes dominate in disturbed forests, while competitive (C) species decline.
- Primary forests host diverse epiphytic communities, including Orchidaceae and mid-stem sciophytic species.
- Forest disturbances simplify the taxonomic and vertical layer structure of epiphytic communities.

## Abstract

One of the most popular approaches in functional plant ecology is the study of CSR strategies based on Grime’s theory. However, this approach to the study of epiphytes has not been used yet. We assumed that the response of epiphytes to disturbances would be different than that of terrestrial plants. Namely, this would lead to a decrease in epiphytes with the competitive (C) strategy and an increase in the number of stress-tolerants (S) in disturbed forests. We found that in primary forests, representatives of the Orchidaceae family dominate in terms of species number, while in disturbed forests, Orchidaceae and Polypodiaceae dominate. Epiphytes demonstrate a tendency to a more pronounced C- strategy than tropical forest trees and to a more R- strategy than terrestrial herbs. At the same time, most epiphytes gravitate toward the radical S- strategy. In the primary forest, epiphytes adhering to competitive, ruderal, and mixed strategies are widely represented. Representatives of these strategies disappear in secondary forests so that predominantly (S) stress-tolerant and one (C) competitive species remain. In the studied secondary formations of tropical forest, the lower forest layer is occupied by succulent orchids and ferns. Undisturbed tropical forest is characterized by the presence of sciophytic and mid-stem epiphytes. Disturbance of the tropical forest structure leads to the loss of epiphytic species of the lower synusiae, while the advantage passes to stress-tolerant succulents. Thus, the change in the functional diversity of epiphytes is directly related to the change in the structure and layering of the forest canopy