How do lianas and vines influence competitive differences and niche differences among tree species? Concepts and a case study in a tropical forest

1. Lianas and other climbing plants are structural parasites of trees, generally reducing host tree survival, growth, and reproduction, yet their influences on the outcome of competition among tree species have remained largely unexplored. 2. We propose that there are three distinct components to liana-tree interactions: prevalence, defined as the proportion of infested trees; load, defined as the mean liana cover on infested trees; and tolerance, defined as the effect of a given level of infestation on tree population growth rates. We introduce a new metric that integrates these components, the liana burden, defined as the total effect of lianas on per capita population growth rates given current prevalence, load, and tolerance. Using these metrics, we quantify variation among 33 co-occurring tropical tree species in liana-tree interactions and its relation with shade-tolerance. 3. The focal tree species vary strongly in liana prevalence, load, tolerance, and burden. Interspecific v...