Modeling the impact of liana infestation on the demography and carbon cycle of tropical forests

Manfredo di Porcia E Brugnera; Félicien Meunier; Marcos Longo; Sruthi M Krishna Moorthy; Hannes De Deurwaerder; Stefan A Schnitzer; Damien Bonal; Boris Faybishenko; Hans Verbeeck

doi:10.1111/gcb.14769

Modeling the impact of liana infestation on the demography and carbon cycle of tropical forests

Glob Chang Biol. 2019 Nov;25(11):3767-3780. doi: 10.1111/gcb.14769. Epub 2019 Sep 11.

Authors

Affiliations

¹ CAVElab - Computational and Applied Vegetation Ecology, Ghent University, Ghent, Belgium.
² Ecological Forecasting Lab, Department of Earth and Environment, Boston University, Boston, MA, USA.
³ Embrapa Agricultural Informatics, Campinas, SP, Brazil.
⁴ Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA.
⁵ Smithsonian Tropical Research Institute, Balboa, Ancon, Panama.
⁶ Department of Biological Sciences, Marquette University, Milwaukee, WI, USA.
⁷ UMR Silva, Université de Lorraine, AgroParisTech, INRA, Nancy, France.
⁸ Earth and Environmental Science Area, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.

Abstract

There is mounting empirical evidence that lianas affect the carbon cycle of tropical forests. However, no single vegetation model takes into account this growth form, although such efforts could greatly improve the predictions of carbon dynamics in tropical forests. In this study, we incorporated a novel mechanistic representation of lianas in a dynamic global vegetation model (the Ecosystem Demography Model). We developed a liana-specific plant functional type and mechanisms representing liana-tree interactions (such as light competition, liana-specific allometries, and attachment to host trees) and parameterized them according to a comprehensive literature meta-analysis. We tested the model for an old-growth forest (Paracou, French Guiana) and a secondary forest (Gigante Peninsula, Panama). The resulting model simulations captured many features of the two forests characterized by different levels of liana infestation as revealed by a systematic comparison of the model outputs with empirical data, including local census data from forest inventories, eddy flux tower data, and terrestrial laser scanner-derived forest vertical structure. The inclusion of lianas in the simulations reduced the secondary forest net productivity by up to 0.46 t_C ha^-1 year^-1 , which corresponds to a limited relative reduction of 2.6% in comparison with a reference simulation without lianas. However, this resulted in significantly reduced accumulated above-ground biomass after 70 years of regrowth by up to 20 t_C /ha (19% of the reference simulation). Ultimately, the simulated negative impact of lianas on the total biomass was almost completely cancelled out when the forest reached an old-growth successional stage. Our findings suggest that lianas negatively influence the forest potential carbon sink strength, especially for young, disturbed, liana-rich sites. In light of the critical role that lianas play in the profound changes currently experienced by tropical forests, this new model provides a robust numerical tool to forecast the impact of lianas on tropical forest carbon sinks.

Keywords: carbon dynamics; dynamic global vegetation model; ecology; lianas; plant functional type; tropical forest.

Publication types

Meta-Analysis
Research Support, Non-U.S. Gov't

MeSH terms

Carbon Cycle
Demography
Ecosystem*
Forests
Panama
Trees
Tropical Climate*