Nuanced qualitative trait approaches reveal environmental filtering and phylogenetic constraints on lichen communities

We propose that a qualitative trait approach based on more detailed
nuanced traits may reveal previously overlooked patterns, especially when
combined with phylogenetic perspectives. By sampling epiphytic lichens and
using a functional approach based on nuanced qualitative traits, such as a
much greater resolution over photobiont identity, type of cortex and
chemical compounds, we evaluated the effects of environmental filtering
and phylogenetic constraints on community assembly along natural
succession of Atlantic rainforest. We found changes in taxonomic,
functional and phylogenetic composition, structure and diversity.
Functional traits such as photobiont genera, type of cortex, reproductive
structures, propagule size and protection strategies showed strong
responses to succession. Mature forests with a closed canopy impose strong
environment filtering that is reflected in lichen species turnover,
limiting diversity, but also holding different functional and phylogenetic
composition. The use of a nuanced qualitative trait approach may overcome
some of the limitations of using this type of traits and show the
importance of often overlooked key lichen functional traits, including
presence of carbon concentrating mechanisms in photobionts and cortex
properties. Furthermore, this is the first study showing how patterns of
phylogenetic assembly along forest succession structure lichen
communities.