Climbing Through Changing Forests: Is Liana Diversity or Morphology Affected by Forest Age or Precipitation?

The importance of lianas in tropical forest processes and diversity has recently been recognized, leading to an increase in studies on liana biomass, abundance, and physiology. In this study, liana species richness, grouped by family, and morphological characters of lianas are evaluated as a function of successional forest age in two neotropical forests: a dry seasonal forest and a moist seasonal forest in Costa Rica and Panama, respectively. Diversity, and morphology are compared between the dry (Costa Rica) and seasonally moister (Panama) forests. Vegetative characters examined include climbing mechanism, leaf organization, leaf margin and petiole length. Reproductive characters include diaspore type, diaspore and seed size, and seeds per fruit. Bignoniaceae, Sapindaceae and Fabaceae were the most species rich families at each site. Celastraceae was more species rich in the moist forest while Malpighiaceae was more species rich in the dry forest. The proportion of tendrilling lianas was similar in the dry (50%) and moist (48%) forest, and there were no significant changes of dominant climbing mechanism among species across forest age. The other vegetative characters did not vary significantly across forest age at either site and were not different between sites. Wind dispersal was more dominant for species in the dry forest (76%) than the moist forest (60%). The relative number of animal dispersed species increased with successional forest age in Panama, perhaps due to dispersers’ response to changes in forest stand structure. Seed size did not vary significantly across forest age or between sites, most likely due to canopy gaps maintaining diversity in older forests. This study suggests that family level species richness and the morphology of liana communities may not respond strongly to forest age or to sites with variable seasonality in the neotropics, however evaluation using abundance data is in order.Honors (Bachelor's)Honors (Bachelor's)Program in the EnvironmentUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/62111/1/Koski_Thesis_2009.pd