Functional traits behind the association between climbers and subordinate woody species
Functional differences among climber species may reflect different strategies to cope with the environment created by the set of trees and shrubs used to reach the canopy. Moreover, climber diversity may be promoted and maintained by associations with subordinate woody species. Considering that functional differences among climbers may reflect this relationship, we aimed to identify trait differences among climbers, and the traits related to the association between climbers and woody species.
Restinga de Jurubatiba National Park, a tropical sandy coastal plant community in southeast Brazil.
Relative abundances of climbers and shrubs/trees were surveyed, and climber species were described by a set of traits related to dispersal, establishment and persistence. Principal coordinate analysis was used to identify trait differences among climbers. Further, we performed principal components analysis in a community-weighted mean trait values matrix (CWM) and compared the major pattern of variation with the abundance of dominant and subordinate woody species, and with environmental variables.
The analyses revealed functional traits behind the association between climbers and subordinate woody species. These species are mostly characterized by the presence of latex and dry fruits, anemochorous dispersal and stem twining climbing strategy. They were associated with the subordinate shrub Erythroxylum subsessile. Tendril climbers were more generalist and were also characterized by zoochoric dispersal and the presence of endosperm.
The associative behaviour between climbers and the subordinate shrub E. subsessile is explained by a specific set of traits present in species of the same plant family, Apocynaceae. While stem twiners were positively associated with the specialist nurse E. subsessile, tendril climbers were associated with the dominant nurses. These results offer clues to understand the presence of specialist and generalist groups of climber species in tropical plant communities, as well as community assembly through facilitation driven by subordinate species.