Life history traits of lianas during tropical forest succession
Letcher SG; Chazdon RL
Tropical secondary forests form an important part of the landscape. Understanding functional traits of species that colonize at different points in succession can provide insight into community assembly. Although studies on functional traits during forest succession have focused on trees lianas (woody vines) also contribute strongly to forest biomass species richness and dynamics. We examined life history traits of lianas in a forest chronosequence in Costa Rica to determine which traits vary consistently over succession. We conducted 0.1 ha vegetation inventories in 30 sites. To examine the establishment of young individuals we only included small lianas (0.5–1.5 cm diameter at 1.3 m height). For each species we identified seed size dispersal mode climbing mode and whether or not the seedling is self-supporting. We found a strong axis of variation determined by seed size and seedling growth habit with early successional communities dominated by small-seeded species with abiotic dispersal and climbing seedlings while large-seeded animal-dispersed species with free-standing seedlings increased in abundance with stand age. Contrary to previous research and theory we found a decrease in the abundance of stem twiners and no decrease in the abundance of tendril-climbers during succession. Seed size appears to be a better indicator of liana successional stage than climbing mode. Liana life history traits change predictably over succession particularly traits related to seedling establishment. Identifying whether these trait differences persist into the growth strategies of mature lianas is an important research goal with potential ramifications for understanding the impact of lianas during tropical forest succession.