Liana functional assembly along the hydrological gradient in Central Amazonia

Area of Science:

• Ecology
• Botany
• Forest Science

Background:

• Tropical tree species composition varies with soil hydrology, nutrients, and disturbance.
• Habitat filtering, driven by hydraulic traits, explains tree distribution along hydrological gradients.
• It remains unclear if similar patterns govern liana species composition and trait-environment relationships.

Purpose of the Study:

• Investigate if hydrological gradients, soil fertility, and forest disturbance explain liana species composition.
• Determine if liana species-environment relationships are mediated by leaf and stem wood functional traits.
• Compare liana distribution patterns to those of tropical trees.

Main Methods:

• Sampled liana species composition in 18 1-ha plots across a 64 km² Central Amazonian landscape.
• Measured eleven leaf and stem wood functional traits for 115 liana species (2000 individuals).
• Correlated liana species composition (PCoA) with functional composition (PCA) and tested relationships with environmental gradients.

Main Results:

• Liana species composition strongly correlated with functional composition.
• Both taxonomic and functional compositions were significantly associated with the hydrological gradient.
• Forest disturbance had a minor influence on functional composition; lianas exhibited distinct trait-environment relationships at valley and plateau sites.

Conclusions:

• Liana species employ different functional strategies to cope with varying hydrological conditions.
• Habitat preferences and functional traits explain liana species distributions less directly than previously observed in trees.
• Hydrology is a key driver of liana community assembly and functional trait variation in tropical forests.