Abiotic and biotic drivers of liana community change in an Asian tropical rainforest

Abstract

Lianas have a major influence on community and ecosystem processes in tropical forests, but their dynamics and underlying drivers have rarely been assessed. This study evaluates which demographic processes underlie liana community change and how these demographic processes are driven by abiotic factors (light gaps, soil nutrients, soil water availability, and topography), and biotic factors such as competition by life forms (liana and tree basal area) and the functional properties of the liana community. In a tropical rainforest in Southwest China > 20,000 liana individuals were monitored in 20 1-ha plots and for each plot, average trait values of the liana community were determined for eighteen functional traits that are important for plant performance. Across the 20 plots, changes in liana density were more strongly driven by mortality than by recruitment. Liana recruitment and mortality were driven by biotic factors, especially the functional properties. Liana mortality was higher for acquisitive communities, possibly because of strong competition amongst fast-growing liana species and the short lifespan of pioneers. Liana growth was driven by abiotic factors and increased with elevation and soil water availability. Hence, liana community dynamics are shaped by mortality, and functional properties are more important than the environment. Simultaneously testing the roles of multiple environmental factors and inherent plant characteristics yields better insights into the mechanisms underlying community dynamics.