B122-12
Leaf and Wood Decomposition Across Tropical Lowland and Montane Forests: A Pantropical Study Across Climates

Wednesday, 16 December 2020: 10:33
Virtual
Rebecca Ostertag, Organization Not Listed, Washington, DC, United States, Carla Restrepo, University of Puerto Rico Rio Piedras Campus, San Juan, PR, United States, James W Dalling, University of Illinois at Urbana Champaign, Plant Biology, Urbana, IL, United States, Patrick H Martin, University of Denver, Denver, United States, Shin-ichiro Aiba, Hokkaido University, Sapporo, Japan, Esteban Alvarez-Davila, National Open and Distance University, Bogota, Colombia, Roxana Aragón, Universidad Nacional de Tucumán, Yerba Buena, Argentina, Hazel Chapman, University of Canterbury, Christchurch, New Zealand, Grizelle Gonzalez, USDA Forest Service, International Institute of Tropical Forestry, Vallejo, CA, United States, Sybil G. Gotsch, Franklin and Marshall College, Biology, Lancaster, PA, United States, Achim Haeger, School for Field Studies - Center for Sustainable Development Studies, Atenas, Costa Rica, Juergen Homeier, Georg-August-Universität, Göttingen, Germany, Carlos Iñiguez Armijos, Universidad Técnica Particular de Loja, Loja, Ecuador, Luis Daniel Llambí, University of the Andes, Merida, Venezuela, Georgianne W Moore, Texas A&M University, Department of Ecosystem Science and Management, College Station, TX, United States, Patrícia Vieira Pompeu, Universidade Estadual do Mato Grosso do Sul, Unidade de Aquidauana, Aquidauana, Brazil, Jennifer Powell, Cloudbridge Natural Reserve, Perez Zeledon, Costa Rica, Jorge Andres Ramírez Correa, Universidad del Cauca, Popayán, Colombia, Klara Scharnagl, The Sainsbury Laboratory, Norwich, United Kingdom and Conrado Tobón, Universidad Nacional de Colombia, Medellín, Colombia
Abstract:
Litter decomposition plays a central role in carbon and nutrient cycling, including ecosystem productivity, soil physicochemical properties, the structure of soil organism communities, and the dynamics of food webs. The “hierarchy of factors” hypothesis that states that on a global scale, decomposition rates are controlled primarily by climatic, followed by edaphic, and biological variables. Tropical montane forests (TMF) have hydrological regimes that include constant cloud cover and fog and often differ markedly in forest structure and functioning than tropical lowland forests (TLF). Powers’ et al. (2009) comprehensive leaf litter decomposition study examined the role of climate and mesofauna on decomposition in TLF; we extended this approach to TMF, as part of activities associated with an NSF-funded research coordination network CloudNet. Specifically, we asked (1) how climate affected leaf litter decomposition rates (comparing TMF and TLF sites); and (2) how soil burial in the soil and litterbag mesh size (a proxy for examining mesofauna) affect leaf and wood litter decomposition rates in TMF sites. In 22 TMF sites spanning across the Neotropics, Asia, Africa, and Oceania, litterbags contained either bay leaves or birch popsicle sticks (4 transects x 2 mesh treatments x 2 burial depths x 2 substrates x 2 retrieval times). Leaves always decomposed faster than wood, but the mesh and burial effects were not significant in the TMF. Across biomes, decomposition rate was best predicted by mean annual temperature, isothermality, temperature seasonality, precipitation of the wettest month, and mesh size. For wood, the best fit model included mean diurnal temperature range, precipitation during the coldest quarter, MODIS-derived cloud frequency, and burial depth. The differences between biomes suggest that TMF, with their high rates of carbon storage must be explicitly considered when developing models to elucidate carbon cycling rates in the tropics.
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