Branchfall as a Demographic Filter for Epiphyte Communities: Lessons from Forest Floor-Based Sampling

Area of Science:

• Ecology
• Botany
• Forest Science

Background:

• Vascular epiphyte communities are influenced by environmental factors like substrate and microclimate.
• The impact of tree and branch turnover on epiphyte communities is less understood.

Purpose of the Study:

• To investigate the influence of branch turnover on epiphyte communities.
• To analyze trends in epiphyte abundance, richness, and demographics relative to branch diameter.

Main Methods:

• Conducted surveys of fallen branches and epiphytes on the forest floor across 96 transects in Brazilian and Panamanian rainforests.
• Quantified branch and epiphyte abundance, richness, and adult proportion across varying branch diameters.
• Compared forest floor epiphyte data with existing canopy data in Panama to validate survey methods.

Main Results:

• Branches <2 cm in diameter constituted over 90% of forest floor branches.
• Epiphyte abundance and richness were highest in Brazilian core transects and lowest in Panamanian transects.
• Branch diameter positively correlated with epiphyte abundance, richness, and adult proportion, indicating smaller branches support more epiphytes.

Conclusions:

• Forest floor surveys provide valuable floristic and demographic data, especially for epiphytes on inaccessible, smaller branches.
• Branchfall acts as a significant demographic filter, shaping epiphyte community structure.
• Differences in forest structure and dynamics influence the relationship between branch diameter and epiphyte communities across sites.