Assessing the impact of lianas on tree growth in tropical forests.
Kearsley, E., van der Heijden, G., Schnitzer, S., & Verbeeck, H.
Lianas (woody climbers) are structural parasites and an important component of tropical forests. Due to their strong competition with trees for above and belowground resources, lianas can have a large effect on tree diversity, recruitment, growth and survival, which can further impact tree community composition, carbon storage and carbon, nutrient and water fluxes. Moreover, recent research from the Neotropics has indicated that lianas are proliferating in abundance and biomass related to climate change. Although the drivers behind this liana increase are currently not fully understood, liana proliferation itself can endanger the future of the tropical carbon sink as lianas reduce carbon sequestration and storage in these forests. As tropical forests play an important role in the global carbon cycle, this in turn may lead to increased atmospheric CO2 concentrations, which may have serious implications for climate change. In this study, we use a large-scale liana removal experiment conducted in the Barro Colorado National Monument in the Republic of Panama to investigate the impact of lianas on individual tree growth. The impact of varying severities of liana infestation in the crown on tree growth is assessed, while controlling for growth environment (light, neighboring competition) and species identity using structural equation modeling. The impact of lianas is validated with plots that are liana-free. Different scenarios of future increases in liana abundance and biomass are assessed.