Lianas rapidly colonize early stages of tropical forests, presumably through leaf trait diversification

Abstract

Questions Ecological succession is the process during which ecosystems recover after disturbances. Studies investigating community reassembly during tropical forest succession have rarely compared lianas to trees. We addressed two questions: (1) how do changes in stem density, total basal area and species richness of lianas and trees compare throughout a secondary succession, and to what extent does the relative basal area of lianas change along a secondary succession; and (2) how do the successional trajectories of functional community trait values of lianas and trees compare? Location Yoko forest reserve, central Congo basin. Methods Using univariate Bayesian modeling techniques, we analyzed differences in successional pathways between lianas and trees in terms of community structure, and functional assembly in a replicated chronosequence spanning from young to old‐growth forests. Results We found divergent structural trajectories between lianas and trees along the forest chronosequence. The stem density of lianas peaked at the intermediate stage, while that of trees almost linearly decreased from early to late stages of succession. The basal area of lianas increased at a higher rate than that of trees, which translated into a marginal increase of liana relative basal area over succession. On the contrary, we observed a lower rate of increase in species richness for lianas than trees over succession. We found a progressive convergence in the responses of lianas and trees to changes with succession in terms of specific leaf area and leaf nitrogen content, but a diverging response in terms of leaf phosphorus content. These functional composition patterns most probably resulted from environmental filtering, induced by a change from nitrogen to phosphorus limitation as the succession progressed to a mature forest. Conclusions These findings underscore the rapid colonization of tropical forests by lianas after agricultural abandonment, presumably by deploying a more diverse leaf economic spectrum early in succession.