Water table depth modulates productivity and biomass across Amazonian forests

• Published in: Global ecology and biogeography Vol. 31; no. 8; pp. 1571 - 1588
• Main Authors: Sousa, Thaiane R., Schietti, Juliana, Ribeiro, Igor O., Emílio, Thaise, Fernández, Rafael Herrera, Steege, Hans, Castilho, Carolina V., Esquivel‐Muelbert, Adriane, Baker, Timothy, Castro, Wendeson, Mendoza, Abel Monteagudo, Lima, Adriano José Nogueira, Rudas, Agustín, Araujo‐Murakami, Alejandro, Andrade, Ana, Manzatto, Angelo Gilberto, Torres‐Lezama, Armando, Marimon, Beatriz, Marimon, Ben Hur, Burban, Benoit, Ulft, Bert, Herault, Bruno, Quesada, Carlos, Mendoza, Casimiro, Bonal, Damien, Galbraith, David, Neill, David, Oliveira, Edmar A., Hase, Eduardo, Jimenez‐Rojas, Eliana, Vilanova, Emilio, Arets, Eric, Berenguer, Erika, Alvarez‐Davila, Esteban, Honorio Coronado, Eurídice N., Almeida, Everton, Coelho, Fernanda, Elias, Fernando, Brown, Foster, Bongers, Frans, Arevalo, Freddy Ramirez, Lopez‐Gonzalez, Gabriela, Aymard C., Gerardo A., Llampazo, Gerardo Flores, Pardo, Guido, Ramírez‐Angulo, Hirma, Amaral, Iêda Leão, Vieira, Ima Célia Guimarães, Huamantupa‐Chuquimaco, Isau, Comiskey, James A., Espejo, Javier Silva, Aguila‐Pasquel, Jhon, Talbot, Joey, Terborgh, John, Ferreira, Joice, Barroso, Jorcely G., Barlow, Jos, Camargo, José Luís, Stropp, Juliana, Peacock, Julie, Ferreira, Leandro V., Poorter, Lourens, Gamarra, Luis Valenzuela, Aragão, Luiz, Arroyo, Luzmila, Silveira, Marcos, Peñuela‐Mora, Maria Cristina, Vargas, Mario Percy Núñez, Toledo, Marisol, Réjou‐Méchain, Maxime, Kalamandeen, Michelle, Cardozo, Nállarett Dávila, Silva, Natalino, Pitman, Nigel, Banki, Olaf, Graça, Paulo M. L. A., Morandi, Paulo S., Hout, Peter, Naisso, Pétrus, Camargo, Plínio Barbosa, Salomão, Rafael, Thomas, Raquel, Umetsu, Ricardo Keichi, Costa Silva, Richarlly, Martinez, Rodolfo Vasquez, Brienen, Roel, Ribeiro, Sabina Cerruto, Lewis, Simon L., Vieira, Simone Aparecida, Fauset, Sophie, Laurance, Susan, Feldpausch, Ted, Erwin, Terry, Killeen, Timothy, Wortel, Verginia, Moscoso, Victor Chama, Vos, Vincent, Laurance, William, Malhi, Yadvinder, Phillips, Oliver L.
• Format: Journal Article
• Language: English
• Published: Oxford Wiley Subscription Services, Inc 01.08.2022; Wiley
• Subjects: above‐ground biomass; Availability; Biodiversity; Biodiversity and Ecology; Biomass; Botanics; carbon; Climate; Climate change; Deep water; Ecology, environment; Ecosystems; Environmental Sciences; Forest biomass; forest dynamics; Forests; Groundwater; Life Sciences; Moisture content; Productivity; seasonality; Shallow water; Soil conditions; Soil dynamics; Soil properties; Soil water; Systematics, Phylogenetics and taxonomy; tropical ecology; Tropical forests; Vegetal Biology; Water availability; Water deficit; Water depth; Water supply; Water table; Water table depth; Wet climates; Tropical ecology; Groundwater; Carbon; Forest dynamics; Seasonality; Above-ground biomass
• ISSN: 1466-822X; 1466-8238; 1466-822X
• DOI: 10.1111/geb.13531

Aim Water availability is the major driver of tropical forest structure and dynamics. Most research has focused on the impacts of climatic water availability, whereas remarkably little is known about the influence of water table depth and excess soil water on forest processes. Nevertheless, given that plants take up water from the soil, the impacts of climatic water supply on plants are likely to be modulated by soil water conditions. Location Lowland Amazonian forests. Time period 1971–2019. Methods We used 344 long‐term inventory plots distributed across Amazonia to analyse the effects of long‐term climatic and edaphic water supply on forest functioning. We modelled forest structure and dynamics as a function of climatic, soil‐water and edaphic properties. Results Water supplied by both precipitation and groundwater affects forest structure and dynamics, but in different ways. Forests with a shallow water table (depth <5 m) had 18% less above‐ground woody productivity and 23% less biomass stock than forests with a deep water table. Forests in drier climates (maximum cumulative water deficit < −160 mm) had 21% less productivity and 24% less biomass than those in wetter climates. Productivity was affected by the interaction between climatic water deficit and water table depth. On average, in drier climates the forests with a shallow water table had lower productivity than those with a deep water table, with this difference decreasing within wet climates, where lower productivity was confined to a very shallow water table. Main conclusions We show that the two extremes of water availability (excess and deficit) both reduce productivity in Amazon upland (terra‐firme) forests. Biomass and productivity across Amazonia respond not simply to regional climate, but rather to its interaction with water table conditions, exhibiting high local differentiation. Our study disentangles the relative contribution of those factors, helping to improve understanding of the functioning of tropical ecosystems and how they are likely to respond to climate change.